PAM RTM 2014 User Guide Tutorials
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PAM-RTM 2014 User’s Guide & Tutorials PAM-RTM 2014 USER’S GUIDE & TUTORIALS The documents and related know-how herein provided by ESI Group subject to contractual conditions are to remain confidential. The CLIENT shall not disclose the documentation and/or related know-how in whole or in part to any third party without the prior written permission of ESI Group. © 2014 ESI Group. All rights reserved. April 2014 GR/PART/14/01/00/A PAM-RTM 2014 © 2014 ESI Group i USER’S GUIDE & TUTORIALS (released: Apr-14) CONTENTS INTRODUCTION 1 Presentation of Liquid Composite Molding------------------------------------------ 1 RTM Process -------------------------------------------------------------------------------4 Motivation of Filling Simulations -------------------------------------------------------4 Modeling -------------------------------------------------------------------------------------4 Credits -------------------------------------------------------------------------------------- 12 PAM-RTM USER'S GUIDE 15 Introduction -------------------------------------------------------------------------------- 15 Presentation of the User Interface -------------------------------------------------- 16 Interaction with the Mouse ------------------------------------------------------------ 17 Toolbars ----------------------------------------------------------------------------------- 18 Model Explorer --------------------------------------------------------------------------- 23 Message Pane --------------------------------------------------------------------------- 24 File Menu ---------------------------------------------------------------------------------- 25 File > New --------------------------------------------------------------------------------- 25 File > Open ------------------------------------------------------------------------------- 26 File > Close ------------------------------------------------------------------------------- 27 File > Save -------------------------------------------------------------------------------- 27 File > Save As---------------------------------------------------------------------------- 28 File > Import > Mesh -------------------------------------------------------------------- 28 File > Import > Scalar Fields ---------------------------------------------------------- 28 File > Import > Draping Results ------------------------------------------------------ 29 File > Export > Mesh ------------------------------------------------------------------- 30 File > Export > PAM-RTM Scalar Field -------------------------------------------- 30 File > Clear > Scalar Fields ----------------------------------------------------------- 30 File > Clear >Laminate ----------------------------------------------------------------- 30 File > Save Image ----------------------------------------------------------------------- 30 File > Generate AVI --------------------------------------------------------------------- 30 File > Print--------------------------------------------------------------------------------- 31 File > Print Preview --------------------------------------------------------------------- 31 File > Print Setup ------------------------------------------------------------------------ 31 Selection Menu --------------------------------------------------------------------------- 32 Selection Filter --------------------------------------------------------------------------- 32 Selection > Pick Normal Vector ------------------------------------------------------ 32 Selection > Pick Normal Vector and Zone----------------------------------------- 33 Selection > Pick Zone ------------------------------------------------------------------ 33 Selection > Pick Boundary ------------------------------------------------------------ 34 Selection > Pick Free Edge ----------------------------------------------------------- 34 Selection > Zone ID --------------------------------------------------------------------- 35 Selection > Entity ID -------------------------------------------------------------------- 36 Selection > Bounding Box ------------------------------------------------------------- 36 Selection > Select All ------------------------------------------------------------------- 37 Selection > Unselect All (filter) ------------------------------------------------------- 37 CONTENTS USER’S GUIDE & TUTORIALS (released: Apr-14) ii PAM-RTM 2014 © 2014 ESI Group Selection > Unselect All (no filter) --------------------------------------------------- 37 Selection > Set Scalar Field Value -------------------------------------------------- 37 Selection > Info Summary ------------------------------------------------------------- 37 Selection > Info Detailed--------------------------------------------------------------- 37 Groups Menu ----------------------------------------------------------------------------- 38 Groups > Create ------------------------------------------------------------------------- 38 Groups > Add To ------------------------------------------------------------------------ 38 Groups > Remove From --------------------------------------------------------------- 38 Groups > Change ID-------------------------------------------------------------------- 38 Groups > Contact Interface ----------------------------------------------------------- 38 Groups > Mold/Cavity Interface ------------------------------------------------------ 39 Groups > Nodes to Faces ------------------------------------------------------------- 41 Groups > Faces to Nodes ------------------------------------------------------------- 41 Groups > Delete (Pick) ----------------------------------------------------------------- 41 Groups > Delete (ID) ------------------------------------------------------------------- 41 Groups > Info Summary --------------------------------------------------------------- 41 Groups > Info Detailed ----------------------------------------------------------------- 41 Mesh Menu -------------------------------------------------------------------------------- 42 Mesh > Remesh > Injection Point --------------------------------------------------- 42 Mesh > Remesh > Runner ------------------------------------------------------------ 43 Mesh > Orientations > K1 ------------------------------------------------------------- 45 Mesh > Orientations > Set Vectors-------------------------------------------------- 45 Mesh > Orientations > Project Vectors --------------------------------------------- 45 Mesh > Orientations > Set K from Selected Nodes ----------------------------- 45 Mesh > Orientations > Set K Orthogonal ------------------------------------------ 46 Mesh > Orientations > Align Plies --------------------------------------------------- 46 Mesh > Orientations > Reverse ------------------------------------------------------ 47 Mesh > Orientations > Project on Skin --------------------------------------------- 47 Mesh > Orientations > Interpolate --------------------------------------------------- 47 Mesh > Orientations > Map Draping Results ------------------------------------- 55 Mesh > Orientations > Compute Local Permeability on Shells --------------- 56 Mesh > Orientations > Compute Local Permeability on Solids --------------- 63 Mesh > Orientations > Compute Local Permeability from Zones ------------ 64 Mesh > Orientations > Compute Thickness from Skins ------------------------ 64 Mesh > Orientations > Clear on Selection ----------------------------------------- 65 Mesh > Orientations > Clear All ------------------------------------------------------ 66 Mesh > Transform > Set Zone ID---------------------------------------------------- 66 Mesh > Transform > Offset Zone Ids ----------------------------------------------- 67 Mesh > Transform > Extrude --------------------------------------------------------- 67 Mesh > Transform > Split Quads ---------------------------------------------------- 70 Mesh > Transform > Split Solid Elements ----------------------------------------- 71 Mesh > Transform > Scale ------------------------------------------------------------ 71 Mesh > Transform > Translate ------------------------------------------------------- 71 Mesh > Transform > Rotate----------------------------------------------------------- 72 Mesh > Transform > Extract Shell from Solid------------------------------------- 72 Mesh > Create > Node ----------------------------------------------------------------- 74 Mesh > Cleanup > Merge Coincident Nodes ------------------------------------- 74 Mesh > Cleanup > Reverse Normals (selection) -------------------------------- 74 Mesh > Cleanup > Align Normals (auto) ------------------------------------------- 74 Mesh > Cleanup > Delete Unreferenced Nodes --------------------------------- 74 CONTENTS PAM-RTM 2014 © 2014 ESI Group iii USER’S GUIDE & TUTORIALS (released: Apr-14) Mesh > Cleanup > Delete Selected Entities -------------------------------------- 75 Mesh > Cleanup > Delete Degenerate Elements -------------------------------- 75 Mesh > Cleanup > Swap Diagonal -------------------------------------------------- 75 Mesh > Check ---------------------------------------------------------------------------- 75 Mesh > Info ------------------------------------------------------------------------------- 76 Mesh > Info Pick ------------------------------------------------------------------------- 76 View Menu --------------------------------------------------------------------------------- 77 View > Curve Viewer ------------------------------------------------------------------- 77 View > Orientations > K1 Only ------------------------------------------------------- 77 View > Orientations > K2 Only ------------------------------------------------------- 77 View > Orientations > K1 and K2 ---------------------------------------------------- 78 View > Orientations > None----------------------------------------------------------- 78 View > Outline > Part ------------------------------------------------------------------- 78 View > Outline > Free Edges --------------------------------------------------------- 78 View > Outline > Plies ------------------------------------------------------------------ 78 View > Flow Front ----------------------------------------------------------------------- 79 View > Normal Vectors----------------------------------------------------------------- 80 View > Zones Visibility ----------------------------------------------------------------- 80 View > Cutting Plane ------------------------------------------------------------------- 80 View > Post-Processing --------------------------------------------------------------- 82 View > Symmetry ------------------------------------------------------------------------ 84 View > Delete N Last Steps ----------------------------------------------------------- 84 View > Set Same Viewpoint ---------------------------------------------------------- 85 View > Options > Paths ---------------------------------------------------------------- 85 View > Options > Display -------------------------------------------------------------- 87 View > Options > Colors --------------------------------------------------------------- 89 View > Color Scale ---------------------------------------------------------------------- 90 View > Color Schemes ----------------------------------------------------------------- 91 View > Lights ----------------------------------------------------------------------------- 91 View > Refresh--------------------------------------------------------------------------- 91 Process Parameters -------------------------------------------------------------------- 92 RTM Simulation -------------------------------------------------------------------------- 92 VARI Simulation ------------------------------------------------------------------------- 94 Heated RTM Simulation --------------------------------------------------------------- 95 Preheating Simulation ------------------------------------------------------------------ 97 Presimulation ----------------------------------------------------------------------------- 98 Curing Simulation ----------------------------------------------------------------------- 98 Compression RTM Simulation ------------------------------------------------------- 99 PAM-QUIKFORM Simulation ------------------------------------------------------- 100 Numerical Parameters---------------------------------------------------------------- 107 RTM Simulation ------------------------------------------------------------------------ 107 VARI Simulation (standard solver only) ------------------------------------------ 115 Heated RTM Simulation ------------------------------------------------------------- 118 Preheating Simulation ---------------------------------------------------------------- 121 Curing Simulation --------------------------------------------------------------------- 123 Presimulation (standard solver only) ---------------------------------------------- 125 PAM-QUIKFORM Simulation ------------------------------------------------------- 126 Function Editor ------------------------------------------------------------------------- 130 Overview -------------------------------------------------------------------------------- 130 User Defined Functions -------------------------------------------------------------- 132 CONTENTS USER’S GUIDE & TUTORIALS (released: Apr-14) iv PAM-RTM 2014 © 2014 ESI Group Function Pool --------------------------------------------------------------------------- 133 Import/Export --------------------------------------------------------------------------- 134 Material Properties of the Resin --------------------------------------------------- 135 General Tab ---------------------------------------------------------------------------- 135 Thermal Tab ---------------------------------------------------------------------------- 138 Chemical Tab -------------------------------------------------------------------------- 139 Material Properties of the Fiber Reinforcements ------------------------------ 142 General Tab ---------------------------------------------------------------------------- 143 Compressibility Tab ------------------------------------------------------------------- 144 Thermal Tab ---------------------------------------------------------------------------- 146 Advanced Tab (Fabrics) ------------------------------------------------------------- 148 Draping Tab ---------------------------------------------------------------------------- 149 Material Properties of Solids -------------------------------------------------------- 150 General Tab ---------------------------------------------------------------------------- 150 Thermal Tab ---------------------------------------------------------------------------- 151 Laminates -------------------------------------------------------------------------------- 152 Material Database --------------------------------------------------------------------- 155 Creation of the Material Database------------------------------------------------- 155 Using the Material Database ------------------------------------------------------- 156 Boundary Conditions------------------------------------------------------------------ 160 Non-Coincident Interfaces----------------------------------------------------------- 165 Sensors----------------------------------------------------------------------------------- 167 Creating Sensors ---------------------------------------------------------------------- 167 Editing Sensors ------------------------------------------------------------------------ 169 Plotting sensors ------------------------------------------------------------------------ 169 Trigger Manager ----------------------------------------------------------------------- 171 Curve Viewer --------------------------------------------------------------------------- 175 Importing Curves ---------------------------------------------------------------------- 175 Settings ---------------------------------------------------------------------------------- 176 Saving Images ------------------------------------------------------------------------- 182 Running the Simulation from a Command Window -------------------------- 183 Windows --------------------------------------------------------------------------------- 183 Linux -------------------------------------------------------------------------------------- 184 TUTORIALS 187 Central Injection ------------------------------------------------------------------------ 187 Objective -------------------------------------------------------------------------------- 187 Model of the Part and Physical Parameters------------------------------------- 187 Mesh Import and Visualization of the Zones ------------------------------------ 188 Creation of Groups -------------------------------------------------------------------- 190 Simulation ------------------------------------------------------------------------------- 192 Post-Processing the Results-------------------------------------------------------- 196 Edge Effects – Rectangular Plate ------------------------------------------------- 202 Objective -------------------------------------------------------------------------------- 202 Creation of Groups and Visualization of Zones -------------------------------- 202 Simulation ------------------------------------------------------------------------------- 205 Visualization of Results -------------------------------------------------------------- 206 Edge Effects – Complex Shape---------------------------------------------------- 208 Objective -------------------------------------------------------------------------------- 208 CONTENTS PAM-RTM 2014 © 2014 ESI Group v USER’S GUIDE & TUTORIALS (released: Apr-14) Visualization of Groups and Zones------------------------------------------------ 208 Simulation ------------------------------------------------------------------------------- 210 Fiber Orientations---------------------------------------------------------------------- 213 Objective -------------------------------------------------------------------------------- 213 Test Part --------------------------------------------------------------------------------- 213 Fiber Orientations --------------------------------------------------------------------- 213 Visualizing the Simulation Results ------------------------------------------------ 224 Comparison 2D – 2.5D – 3D-------------------------------------------------------- 228 Introduction ----------------------------------------------------------------------------- 228 Simulation Results -------------------------------------------------------------------- 235 Special Effects in the Rib Junction ------------------------------------------------ 237 Conclusion ------------------------------------------------------------------------------ 243 Air Entrapment ------------------------------------------------------------------------- 245 Visualization of Groups and Orientations ---------------------------------------- 245 Vacuum Assisted Resin Infusion (vari) ------------------------------------------ 251 Objectives ------------------------------------------------------------------------------- 251 Mesh Modification --------------------------------------------------------------------- 251 Simulation ------------------------------------------------------------------------------- 253 Landing Gear --------------------------------------------------------------------------- 265 Introduction ----------------------------------------------------------------------------- 265 Analysis of a Landing Gear --------------------------------------------------------- 266 Analysis of Simulation Results ----------------------------------------------------- 268 Conclusion ------------------------------------------------------------------------------ 269 Mesh Extrusion ------------------------------------------------------------------------- 270 Objectives ------------------------------------------------------------------------------- 270 Mesh Extrusion ------------------------------------------------------------------------ 270 Process and Numerical Parameters ---------------------------------------------- 277 Launching the Simulation and Post-Processing ------------------------------- 279 Non-Isothermal Injection ------------------------------------------------------------- 280 Objective of the Analysis ------------------------------------------------------------ 280 Geometry Description ---------------------------------------------------------------- 280 Visualization of Groups -------------------------------------------------------------- 281 Simulation Parameters --------------------------------------------------------------- 281 Simulation Cases ---------------------------------------------------------------------- 289 Curing of a Plate ----------------------------------------------------------------------- 298 Visualization of the Mesh and Groups-------------------------------------------- 298 Simulation Parameters --------------------------------------------------------------- 299 Simulation Results -------------------------------------------------------------------- 303 Curing of a Part with an Insert------------------------------------------------------ 305 Objectives of the Analysis ----------------------------------------------------------- 305 Visualization of Groups and Zones------------------------------------------------ 305 Simulation Parameters --------------------------------------------------------------- 307 Curing Simulations -------------------------------------------------------------------- 311 Conclusion ------------------------------------------------------------------------------ 323 Thermal Contact Resistance ------------------------------------------------------- 324 Objectives ------------------------------------------------------------------------------- 324 Creation of Groups -------------------------------------------------------------------- 324 Simulation ------------------------------------------------------------------------------- 326 Non-Isothermal 3D – Fibers Orientation ----------------------------------------- 330 CONTENTS USER’S GUIDE & TUTORIALS (released: Apr-14) vi PAM-RTM 2014 © 2014 ESI Group Objective of the Analysis ------------------------------------------------------------ 330 Geometry Description ---------------------------------------------------------------- 330 Zones of the Part ---------------------------------------------------------------------- 331 Fiber Orientations --------------------------------------------------------------------- 332 Material parameters ------------------------------------------------------------------ 333 Material Assignment ------------------------------------------------------------------ 337 Simulation Stage1: Preheating ----------------------------------------------------- 338 Simulation Stage2: Heated RTM -------------------------------------------------- 342 Simulation Stage 3: Curing---------------------------------------------------------- 345 Analysis of the Results --------------------------------------------------------------- 347 Conclusion ------------------------------------------------------------------------------ 350 User Defined Functions -------------------------------------------------------------- 351 Objectives ------------------------------------------------------------------------------- 351 Windows Procedure ------------------------------------------------------------------ 351 Linux Procedure ----------------------------------------------------------------------- 355 Setting the parameters in the PAM-RTM GUI ---------------------------------- 356 User functions for resin specific heat and effective conductivity ----------- 357 One Shot Filling Simulation --------------------------------------------------------- 361 Objectives ------------------------------------------------------------------------------- 361 Material Properties -------------------------------------------------------------------- 361 Boundary Conditions ----------------------------------------------------------------- 364 One Shot Parameters ---------------------------------------------------------------- 365 Launching the Simulation and Post-processing -------------------------------- 366 GenPorts --------------------------------------------------------------------------------- 368 Objectives ------------------------------------------------------------------------------- 368 Material Properties and Boundary Conditions ---------------------------------- 368 GenPorts Parameters ---------------------------------------------------------------- 369 Launching the Simulation and Post-processing -------------------------------- 371 Sequential Injection (Trigger Manager) ------------------------------------------ 373 Objectives ------------------------------------------------------------------------------- 373 Boundary Conditions ----------------------------------------------------------------- 373 Material definition---------------------------------------------------------------------- 375 Sensors ---------------------------------------------------------------------------------- 376 Trigger Manager ----------------------------------------------------------------------- 376 Launching the Simulation and Post-processing -------------------------------- 379 Velocity optimization ------------------------------------------------------------------ 383 Objectives ------------------------------------------------------------------------------- 383 Process and Numerical Parameters ---------------------------------------------- 383 Material Properties -------------------------------------------------------------------- 385 Boundary Conditions ----------------------------------------------------------------- 385 Launching the Simulation and Post-processing -------------------------------- 387 Compression RTM -------------------------------------------------------------------- 394 Objective -------------------------------------------------------------------------------- 394 Geometry and Boundary Conditions ---------------------------------------------- 394 Material Characteristics -------------------------------------------------------------- 395 RTM Injection--------------------------------------------------------------------------- 396 Compression RTM Injection -------------------------------------------------------- 399 Conclusion ------------------------------------------------------------------------------ 408 Local Permeability from Draping Results---------------------------------------- 409 Introduction ----------------------------------------------------------------------------- 409 CONTENTS PAM-RTM 2014 © 2014 ESI Group vii USER’S GUIDE & TUTORIALS (released: Apr-14) Map Draping Results ----------------------------------------------------------------- 410 Local Permeability Calculation ----------------------------------------------------- 418 Filling Simulation ---------------------------------------------------------------------- 422 Local Permeability from Draping Results (Advanced) ----------------------- 426 Objectives ------------------------------------------------------------------------------- 426 Map Draping Results ----------------------------------------------------------------- 427 Local Permeability Calculation ----------------------------------------------------- 430 PAM-QUIKFORM ---------------------------------------------------------------------- 438 Objectives ------------------------------------------------------------------------------- 438 Process and Numerical Parameters ---------------------------------------------- 438 Launching the Simulation and Post-Processing ------------------------------- 443 Credits ----------------------------------------------------------------------------------- 449 CONTENTS PAM-RTM 2014 © 2014 ESI Group 1 USER’S GUIDE & TUTORIALS (released: Apr-14) INTRODUCTION PRESENTATION OF LIQUID COMPOSITE MOLDING "Liquid Composite Molding" (LCM) is a generic term for a family of related processes in composite manufacturing, in which continuous fibers used as reinforcement are first placed in the bottom part of a mold, then a polymer matrix is injected as liquid resin into the cavity. After curing, the part is demolded. The resin impregnation of the preform is governed by Darcy's law, the general model describing fluid flows through porous media. Although LCM technologies are used mainly to manufacture composites with thermosetting resins, thermoplastic resins can also be processed under certain conditions. The main LCM process variants are stated below: - Standard or closed mold RTM ("Resin Transfer Molding"): closed mold injection of resin that can be performed also after vacuum has been made in the mold. This latter alternative is often called "Vacuum Assisted Resin Transfer Molding" VARTM). - Non isothermal RTM . The mold and/or the resin are heated to facilitate the resin flow by decreasing resin viscosity. - Injection-compression ("Compression Resin Transfer Molding" - CRTM). The top part of the mold is opened slightly during resin injection in order to increase the porosity of the reinforcement and facilitate mold filling. Transverse flow is considered as negligible for this process. - Vacuum Assisted Resin Infusion - VARI. The reinforcement is covered by a flexible membrane, which is sealed and under which vacuum is done. - Liquid Resin Infusion – LRI. Often, VARI is considered as a variant of LRI. What distinguishes LRI is a use of a highly permeable layer; it could be a net bleeder set over one side of the preform or an internal reinforcement layer. The resin flow is a combination of transverse flow and surface flow; transverse flow is significant for this process and can not be neglected. Note also that in a quite similar - and patented - process variant called SCRIMP, a flexible membrane is also used with vacuum together with a skin of much higher permeability on top of the reinforcement. - Resin Film Infusion - RFI. A resin film is positioned on top of the reinforcement. Resin flow occurs through the thickness of the part, as the resin film is heated and compressed by a press. - Autoclave RTM. This hybrid process variant uses an autoclave to control the pressure on top of a flexible membrane under which resin is injected. The INTRODUCTION Presentation of Liquid Composite Molding USER’S GUIDE & TUTORIALS (released: Apr-14) 2 PAM-RTM 2014 © 2014 ESI Group membrane is semi-permeable, in the sense that it allows air to be expelled during resin injection, but it is impermeable to resin. INTRODUCTION Presentation of Liquid Composite Molding PAM-RTM 2014 © 2014 ESI Group 3 USER’S GUIDE & TUTORIALS (released: Apr-14) These LCM process variants are illustrated in the following figures: p closed mold RTM heated RTM injection-compression (CRTM) Vacuum Assisted Resin Infusion (VARI) heated press p heating tubes resin film autoclave controlled pressure inlet tube flexible semi -permeable membrane preform Resin Film Infusion (RFI) Autoclave RTM INTRODUCTION Presentation of Liquid Composite Molding USER’S GUIDE & TUTORIALS (released: Apr-14) 4 PAM-RTM 2014 © 2014 ESI Group As there is a large number of LCM process variants currently in use or under development, it is not possible to describe all of them, nor even the details of the ones presented above. This information is usually part of the corporate know-how. Very often LCM simulations must be tailored to meet the diversity of injection processes. RTM Process The most frequently used resins are polyester, polyurethane, phenolic and epoxy systems. The reinforcements are made of glass, carbon or kevlar fibers. In the RTM process, resin is injected at a relatively weak pressure, usually less than 5 bars to prevent fiber washing by the resin flow. The injection can be performed using one or several injection ports, injection lines or a tree of injection channels. It is necessary to select a good configuration of injection ports and vents to avoid dry spots and minimize filling time. This is precisely the goal of numerical simulation. Motivation of Filling Simulations In numerous situations, numerical simulations of mold filling can be of great help to avoid problems such as resin rich areas, air bubbles, dry spots, zones of high porosity, as well as the formation of cracks following cure shrinkage. Most of the time, for large parts, and even for small parts with ribbed connections, it is advantageous to determine by simulation the optimal positions of injection ports and vents. Simulation software has been developed in the last few years to assist in the design of RTM molds. It is more economic to perform simulations before construction of the mold than to modify an existing mold. The more complex is the mold, the more costly are mistakes in mold design. This is the reason why, even for small parts, it is useful to perform a preliminary study by simulation. Modeling The numerical simulation of the RTM process implies the modeling of three categories of physical phenomena: the resin flow through the fiber bed, the thermal analysis of heat exchanges in the part and with the mold, and finally, the chemical reaction of the resin. Flow in a Porous Medium In the RTM process, the resin flows through a fibrous reinforcement, which can be considered as a porous medium. In this case, the flow of resin is governed by Darcy’s law, which states that the flow rate of resin per unit area is proportional to the pressure gradient and inversely proportional to the viscosity of the resin. The constant of proportionality is called the permeability of the porous medium. It is independent of the fluid, but it depends on the direction of the fibers which form the reinforcement (if the porous medium is no isotropic). The reinforcement is initially dry and the resin must fill the cavity. Capillary forces of attraction or repulsion act to the forehead of flow. INTRODUCTION Presentation of Liquid Composite Molding PAM-RTM 2014 © 2014 ESI Group 5 USER’S GUIDE & TUTORIALS (released: Apr-14) These forces, which depend on the surface tension of the resin and on its ability to adhere to the surface of fibers, have the effect of either reducing or increasing the effective pressure at the resin front. However, they are considered as sufficiently small in front of the pressure field in RTM to be neglected by numerical models. Darcy’s law states that the fluid velocity is proportional to the pressure gradient: → V = − K → µ ∇P where: - K : permeability tensor - µ : viscosity of the resin - V : Darcy’s velocity - P : pressure In order to preserve the balance of resin mass, the velocity field must satisfy the divergence condition : ∇.V = 0 By combining these two equations, we get K ∇. ∇P = 0 µ If Ω denotes the cavity and dΩ its boundary, boundary conditions are necessary to solve the problem. These conditions can be of two types: - Dirichlet conditions, or imposed pressure: p = f ( x, y , z ) This means that the pressure is specified on part of the boundary dΩ. This is also the case when the injection is made under vacuum; the pressure at the inlet gate is then simply the air pressure. At the inlet gates, the pressure is equal to the value fixed by the injection pump. - Neumann conditions, or imposed flow rate at the inlet gates: V .n = Q An alternative to RTM is Vacuum Assisted Resin Infusion (VARI), which uses flexible covers instead. The VARI process inherits the basic principles from RTM, while requiring vacuum in the cavity where the reinforcement has to be placed. The vacuum is mainly intended to reduce voids formation and facilitate the transfer of the resin, which is injected at the ambient pressure. INTRODUCTION Presentation of Liquid Composite Molding USER’S GUIDE & TUTORIALS (released: Apr-14) 6 PAM-RTM 2014 © 2014 ESI Group However, in the case of deformable media, one has to derive the governing equations starting from the resin mass balance in order to ensure conservation. The continuity equation, considering the resin and the fibers material as incompressible, is expressed as: div φ ⋅ Vr = − div Vs ( ) ( ) Where φ is the porosity, Vr is the resin velocity and Vs is the solid velocity. Finally, Darcy’s law enables to write: [K ] div ∇P µ = div Vs = dε dt ( ) where ε represents an infinitesimal deformation of the fiber bed. This equation is the general form of mass conservation for the consolidation problem and is often called the unified Darcy equation. An additional equation is introduced to follow the deformation of the cover. A quasisteady state is assumed to prevail at any point on the cover surface. In the present case, the sum of the compaction pressure (Pc) and the resin pressure (Pr) has to balance the external pressure (Pext) acting on the cover surface. This can be formulated as: Pc + Pr = Pext The knowledge of the resin pressure and the external pressure allows the user to obtain at each time step the thickness of the cavity from the compaction law of the reinforcement. Therefore, compaction curve plays a major role in this approach. The flow is solved using a non-conforming finite element approximation. The pressure is discontinuous along the inter-element boundaries except at the middle nodes, as shown below for a triangular element. Contrary to conforming finite elements, the computed Darcy flow rates remain continuous across the boundary of elements. Instead of associating fill factors with the nodes of the mesh as in the conforming finite element, they are based on the elements of the mesh. N1 1 3 y 2 INTRODUCTION Presentation of Liquid Composite Molding x PAM-RTM 2014 © 2014 ESI Group 7 USER’S GUIDE & TUTORIALS (released: Apr-14) The pressure is interpolated using linear shape functions Ni as p ( x, y ) = a + bx + cy = ∑ Pi N i ( x, y ) i and N i (x ∗j , y ∗j ) = δ ij = { 0, if i≠ j 1, if i= j where ( x ∗j , y ∗j ) are the middle nodes at the element boundaries. Permeability of the Reinforcement The permeability characterizes the relative facility of a viscous liquid to impregnate a porous medium. This physical property of the porous medium (cloth, fabric, fiber mat, etc.) depends on the fiber volume fraction (degree of compaction) and on the draping of the plies. The permeability is usually denoted by K and its unit is m2. The permeability of reinforcements in their principal directions is determined experimentally. Thermal Phenomena The part lies in the cavity of the mold. It consists of fibrous reinforcements and resin, which first fills up the mold and then becomes progressively polymerized. Heat transfer phenomena have a strong influence on mold filling and resin curing. Indeed, the temperature of the resin governs the reactivity of the polymerization reaction. Temperature also has an influence on mold filling, since the viscosity of the resin depends on temperature. Thermal simulations are therefore delicate to conduct because of all the related phenomena. Firstly, heat is transferred by conduction between the fibers and the resin. Secondly a convective transport of heat occurs during the filling of the cavity by the resin. Finally, heat is produced by the exothermic chemical reaction of resin polymerization. Some heat is also created by the viscous dissipation during the resin flow, but to a lesser degree than the heat originating from the chemical reaction. The temperature field is governed by the general equation: ∂T Dα + ρ r c prV • ∇T = ∇ • {k • ∇T } − ρ r ∆h ρC p ∂t Dt where T denotes the temperature, t denotes the time, ρ is the density, Cp is the specific heat, k is the heat conduction coefficient tensor, the subscript r designates the resin, ∆h is the total enthalpy of the polymerization of the resin, α is the resin cure. There are three kinds of temperature boundary conditions: - Prescribed temperature boundary condition: T = T0 INTRODUCTION Presentation of Liquid Composite Molding USER’S GUIDE & TUTORIALS (released: Apr-14) - 8 Heat flux boundary condition: PAM-RTM 2014 © 2014 ESI Group ∂T =q ∂n ∂T = h(T∞ − T ) , where h is the heat ∂n convection coefficient, T∞ is the environmental temperature. Heat convection boundary condition: This general equation permits to treat the steps of pre-heating, filling and curing. During the filling step, it is used with effective properties: - For non-impregnated fibers: ρC p = φρ a C pa + (1 − φ ) ρ f C pf k = φk a + (1 − φ )k f - For impregnated fibers: ρC p = φρ r C pr + (1 − φ ) ρ f C pf k = ke + k D where the subscript r stands for the resin, f for the fibers and a for the air. In general, thermal properties of the air are neglected. The effective conductivity tensor ke of the composite is averaged in each direction. Like the permeability tensor K, the heat conduction coefficient tensor k reduces to a scalar for the isotropic fiber preform. The coefficient kD represents the thermal dispersion tensor arising from hydrodynamic dispersion. It can be evaluated as a function of Peclet number, but its influence is small as long as the fluid velocity is weak. However starting with PAM-RTM™ 2008, it is now possible to take into account thermal dispersion. The following paragraphs describe how it is modeled. Experimental results showed that dispersion depends on Prandtl and Reynolds numbers and that Peclet number can approximate hydrodynamics and heat transfer phenomena at the pore level. Based on this, Delaunay et al. further extended this approach and showed experimentally that both transverse and axial dispersions can be modeled empirically using a mixing length approach, by correcting the components of the thermal conductivity with an expression that depends on Peclet number as follows: λtrans = λ stat (1 + 0.1Pe ) INTRODUCTION Presentation of Liquid Composite Molding PAM-RTM 2014 © 2014 ESI Group 9 USER’S GUIDE & TUTORIALS (released: Apr-14) λ axial = λ stat (1 + 0.8Pe ) Peclet number Pe is defined here as: Pe = vf l a where, vf the observed velocity of the flow front (m/s), connected with Darcy velocity by the relation v f = v φ ( φ denotes the porosity of the fibrous reinforcement) l characteristic length (m) a thermal diffusivity (m2 /s) The characteristic length is referred to as the characteristic scale of the elliptical shape of a compressed fiber tow, In which case it is given by: l = ab The following describes the thermal contact resistance. In a general way, when two solids (parts of a mold, reinforcement) are in contact, because of their roughness and the non-flatness of their surfaces, the contact is never carried out on all apparent surface. Between the zones of contact remains an interstitial space, which is a zone with low conductivity. The temperature field is thus considerably disturbed. The introduction of a thermal contact resistance Rth allows to neglect the thickness of the contact zone and to replace the abrupt variation in temperature by a true discontinuity. y T2(y) 2nd solid e contact zone 1st solid T1(y) x Illustration of the thermal contact resistance INTRODUCTION Presentation of Liquid Composite Molding USER’S GUIDE & TUTORIALS (released: Apr-14) 10 PAM-RTM 2014 © 2014 ESI Group T1 − T2 where T1 and T2 are the Rth contact temperatures on the interface and ϕ the heat transfer. Its surface value is determined by the following relation: The thermal contact resistance Rth is defined by ϕ = Rth = e (m2W-1K) k Where e is the thickness of the disturbed zone and k is often the thermal conductivity of the air. Thus, we can consider gaps in the mold or ribs in the reinforcement, by affecting locally a value of thermal resistance. The source term on the right side of the general equation of thermal phenomena accounts for the internal heat generated by the exothermic chemical reaction in thermoset resin system. This source term is usually assumed to be proportional to the Dα . reaction rate Dt Viscosity of the Resin The viscosity of the resin depends on temperature and on the degree of conversion. The dependence on the degree of conversion is very strong, since it is usually assumed that viscosity reaches infinity when the resin comes to gelation. The dependence of viscosity on temperature and the degree of conversion is modeled by a constitutive law. PAM-RTM™ offers several options to model viscosity: - Constant viscosity. - Viscosity function of the temperature from a predefined model µ (T ) = A ⋅ exp( B ⋅ T ) where A and B are two user specified constants. - Viscosity function of temperature and of resin rate of conversion from a predefined model, where A, B and κ are characteristic constants of the resin: B + κ ⋅α T µ (T , α ) = A ⋅ exp - Viscosity µ = f(T,α) function of temperature and of the resin rate of conversion, such as in the following frequently used model: T α gel µ (T , α ) = B ⋅ exp b ⋅ T α gel − α c1 + c2 ⋅α where B, Tb, αgel, C1 and C2 are user defined characteristic constants of the resin. INTRODUCTION Presentation of Liquid Composite Molding PAM-RTM 2014 © 2014 ESI Group 11 USER’S GUIDE & TUTORIALS (released: Apr-14) Kinetics of Resin Polymerization The software permits to define a kinetics of polymerization of the resin from the model of Kamal-Sourour. The general shape of the equation of Kamal-Sourour for a resin with n components is the following: n α = ∑ Ciαi i =1 dα i m p = K i (T ) ⋅ α i i ⋅ (1 − α i ) i dt dα i is the rate of reaction for the ith component in s-1, the values of Ki are dt defined by the law of Arrhenius : Ki=Aiexp(-Ei/RT) where - Ai give the number of useful shocks to reactions, - Ei are the energies of activation of the chemical reaction, - mi and pi are exponents characterizing the sensitivity of each autocatalytic reaction, - Ci are the weights of each reaction. Coupling of Physical Phenomena The following table presents a summary of the main phenomena that come into play in the RTM process. All these phenomena are strongly coupled and PAM-RTM™ is able to simulate them. Category Phenomenon Mathematical model Rheologic Resin flow in a porous medium Darcy’s law Variations of viscosity Constitutive law Mold: conduction, loss in surface Heat equation, transfer coefficient (convection-radiance) Thermal Part: conduction, convection, generation of heat, superficial heat loss Chemical Transport of chemical species, diffusion, polymerization Mechanical Mold deformation Equation of convection-diffusion with source term, model with one temperature Equation of convection-diffusion with source term, kinetic model (Kamal-Sourour) Newton’s law Variation of porosity and permeability Empirical models INTRODUCTION Presentation of Liquid Composite Molding USER’S GUIDE & TUTORIALS (released: Apr-14) 12 PAM-RTM 2014 © 2014 ESI Group CREDITS A series of software modules developed by the Chair on Composites of High Performance (CCHP) at École Polytechnique de Montréal have been incorporated in PAM-RTM™ 2008, 2009 and 2010: - Optimization of the void distribution in an RTM composite part through injection flow rate (VoidOpt module); - Rapid RTM flow simulation (OneShot module); - Conditional opening of injection ports and vents during resin injection (TriggerManager module); - Incorporation of simultaneous filling and curing simulations including the overfilling phase and the evacuation of excess resin at the end of the filling cycle; - Optimization using genetic algorithms of injection points locations minimizing fill time (GenPorts module); - Compression RTM and Articulated Compression RTM (ACRTM). INTRODUCTION Credits PAM-RTM 2014 © 2014 ESI Group 13 USER’S GUIDE & TUTORIALS (released: Apr-14) Permeability tensor of the reinforcements is the main material data required for Liquid Composites Molding simulation. However, no normalization of the permeability measurements exists today and significant scatters in measured permeability values between laboratories are observed. In the first stage of an international benchmark exercise on the experimental determination of reinforcement permeability; 11 partners, implementing 16 different measurement techniques between them, compared in-plane permeability data for the examples of fabrics provided by HEXCEL. A second stage of this benchmark study is currently on-going; its purpose is to eliminate sources of scatter and lead to a standardization of measurement methods. Andy Long’s team especially Andreas Endruweit from Nottingham University who participates in that benchmark partnered with ESI Group composites team is sharing non-confidential permeability values measured these last years at the University. Few of these reinforcement data are in the PAM-RTM installation files. A more extensive database that is continuously improved and completed with new data is available on ESI customer portal “MyESI” (local ESI representative must be reached for more information). There are currently no standards for permeability measurement to interpret the provided data; while observed trends (e.g. for the change in permeability as a function of the fiber volume fraction), are of general validity, application of different experimental methods may result in quantitative differences in absolute permeability values. The main purpose of the database is to provide a starting point to PAM-RTM users. INTRODUCTION Credits PAM-RTM 2014 © 2014 ESI Group 15 USER’S GUIDE & TUTORIALS (released: Apr-14) PAM-RTM USER'S GUIDE INTRODUCTION To run a simulation with PAM-RTM™, it is necessary at least to have prepared a mesh of the part to inject using a commercial (GEOMESH, I-DEAS, PATRAN, CATIA) or public domain mesh generator. Whatever the mesh generator you choose, it should have the capability to export a mesh in one of the file formats supported by PAM-RTM™: I-DEAS Universal, PATRAN Neutral, NASTRAN or PAM-SYSTEM. Most commercial mesh generators can export a mesh in NASTRAN format, so it shouldn’t be a problem to work with any mesh generator. The important point is that you work in the CAD system you like to prepare the geometry for meshing, then you mesh in the mesh generator you like, and finally you export the mesh (only nodes and elements, not the boundary conditions or physical properties) in one of the formats supported by PAM-RTM™. The boundary conditions and physical properties are later specified in PAM-RTM™. For simulations involving resolution of Darcy’s equation (RTM, Heated RTM, VARI), PAM-RTM™ uses non-conforming finite elements. Non-conforming finite elements are only available on triangles and tetrahedrons. This means that the cavity has to be meshed with 3 nodes triangles or 4 nodes tetrahedrons. For Heated RTM simulations, the mold could be meshed with 4 nodes quads or 8 nodes bricks. For simulations that don’t solve Darcy’s equation (preheating, curing), quads and bricks could be used to mesh the cavity. In general, having a finite element mesh created by I-DEAS or PATRAN is not enough to launch a simulation with PAM-RTM™. Injection ports and vents have to be defined. In addition, the specification of fiber orientations is not always available in the mesh file. PAM-RTM™ has some tools to specify material orientations and to modify the mesh for injection points and vents. Groups of nodes are created interactively in PAM-RTM™ to be used in the specification of boundary conditions. Once the model is completely specified (material properties, orientations, groups, boundary conditions, etc.), the simulation parameters file (.dtf) is saved and the simulation can be launched from the user interface or from a command window. The latter is mostly used to run the simulation on a Unix server (see chapter Running the Simulation from a Command Window). When the simulation is done, the PAM-RTM™ post-processing functionalities are used to visualize the simulation results. Alternatively, by using the appropriate output format, simulation results can be visualized in I-DEAS or PATRAN. PAM-RTM USER'S GUIDE Introduction USER’S GUIDE & TUTORIALS (released: Apr-14) 16 PAM-RTM 2014 © 2014 ESI Group PRESENTATION OF THE USER INTERFACE The main frame window of PAM-RTM™ is made of 4 areas: - toolbar area [1] - model explorer [2] - 3D graphics windows [3] - message pane [4] Overview of the PAM-RTM user interface PAM-RTM™ is a multi-document, multi-view application, which means that many documents can be opened at the same time, and many views can be created on the same document. This is useful, for example, to visualize the resin pressure field in one view and the temperature field in another view. Or, as shown in the previous image, to visualize a mesh of the part to inject in one view, and a mesh of a ply with fiber orientations in another view. To open a new view on the current document, use the Window->New Window command. When many windows are opened, you can use the Window->Cascade, Window->Tile Horizontally and Window->Tile Vertically commands to have automatic layout of the windows. You can position toolbars in PAM-RTM toolbars any way you like. The recommended setup of toolbars is shown in the previous picture. To move a toolbar you have to click on the left double vertical bar, then drag the toolbar where you want, as shown in the PAM-RTM USER'S GUIDE Presentation of the User Interface PAM-RTM 2014 © 2014 ESI Group 17 USER’S GUIDE & TUTORIALS (released: Apr-14) next picture. When the toolbar is floating, there is an X box that appears in the upper right corner of the window that allows to close it (in case you need more space or you never use some toolbars). To recover a toolbar you closed in such a way, there is a command in the Window menu to show or hide each of the PAM-RTM™ toolbars (ex: Window->Display Toolbar, Window->Selection Toolbar, etc.). Handle to move the toolbars Floating toolbar Interaction with the Mouse The middle mouse button is reserved in PAM-RTM™ to dynamically control the viewpoint: - Middle button alone: rotate - Ctrl + Middle button: pan - Shift + Middle button : zoom The left button is used for selection (picking or area). The selection filter (nodes, faces, elements) is available in the Display toolbar. Selection of elements by area PAM-RTM USER'S GUIDE Presentation of the User Interface USER’S GUIDE & TUTORIALS (released: Apr-14) 18 PAM-RTM 2014 © 2014 ESI Group Toolbars File Toolbar File toolbar This toolbar contains shortcuts to standard Windows commands (from left to right): File->New, File->Open, File->Save, Window->Tile Horizontally, Window->Tile Vertically, Window->Cascade, Help->About. Display Toolbar Display toolbar There are basically 4 display modes in PAM-RTM™ that affect the coloring of display entities: - Default color: in this mode, nodes, edges and faces are displayed using the default colors specified by the user in the Color tab of the View->Options dialog box. - Zones: element faces are colored according to their zone ID. - Groups: if a node or face is part of a group, it is colored according to the group ID. - Scalar Field: faces are colored based on a scalar field value (for example temperature or pressure). The 4 display modes are activated by selecting something in the scalar field roll-down list of the display toolbar [1]. Depending on the context, there will be more or less scalar fields to display. Here is an example. Scalar field list PAM-RTM USER'S GUIDE Presentation of the User Interface PAM-RTM 2014 © 2014 ESI Group 19 USER’S GUIDE & TUTORIALS (released: Apr-14) Examples of the each display mode are shown in the following figures. Surface mesh displayed in Default Color mode Zones display PAM-RTM USER'S GUIDE Presentation of the User Interface USER’S GUIDE & TUTORIALS (released: Apr-14) 20 PAM-RTM 2014 © 2014 ESI Group Groups display Segmented filling scalar field display Here is a description of the other controls available in the display toolbar. - Plot type [2]: Disc or Iso. This parameter has an effect only when visualizing scalar fields. PAM-RTM USER'S GUIDE Presentation of the User Interface PAM-RTM 2014 © 2014 ESI Group 21 USER’S GUIDE & TUTORIALS (released: Apr-14) · Disc is used for example to display a scalar field that was computed at the nodes as a discontinuous fields averaged on each element. · Iso is used to display contours of the current scalar field. Note that if the original field was computed at elements (which is the case for instance for the filling factor), the values will be averaged at the nodes before contours can be generated, which can take a while depending on the mesh size and number of steps. - Selection filter [3]: set the selection filter to Node, Face or Element. For example, use Node if you want to pick nodes, or Element if you want to pick elements. - N, E, F - Time step [5]: drag this slider to visualize the current scalar field step by step. - Animate [6]: starts/stops animation of the current scalar field. Use View->PostProcessing for animation parameters. [4]: check boxes to show or hide nodes, edges, faces. Selection Toolbar This toolbar is used to control the behavior of the selection. For example, if the selection filter is Node and the = button is pushed when some nodes are selected by area, the current selection will be replaced by the new selection. When the + button is pushed, each new selection is added to the current selection. When the – button is pushed, the new selection is removed from the current selection set. Other buttons are available to clear the current selection (equivalent to Selection->Unselect All (no filter)), and to get information about the selected entities (equivalent to Selection->Info Detailed). Selection toolbar (current selection empty) Selection toolbar (non-empty selection) Camera Toolbar Camera toolbar From left to right: - Corner zoom: drag the mouse to define a rectangular area to zoom in. - Zoom out: use after a corner zoom to restore the previous state. - Rotation center: pick a point on the mesh to set the center for rotation and zoom. PAM-RTM USER'S GUIDE Presentation of the User Interface USER’S GUIDE & TUTORIALS (released: Apr-14) - 22 PAM-RTM 2014 © 2014 ESI Group Fit: reset view so that the mesh is completely displayed, in the center of the graphics window. Viewpoint Toolbar Viewpoint toolbar Choose one of the pre-defined viewpoints (along -X axis, +X axis, etc.). Simulation Toolbar Simulation toolbar Start or restart the simulation. Restart is used when simulation was stopped with a CTRL-C and needs to be restarted. Results Toolbar Results toolbar From left to right: - Reload results: reloads all the results files that were generated for this simulation. This is the preferred way to load results in PAM-RTM™. - Probe: opens the Probe dialog box, allowing the user to pick an arbitrary point on the mesh and display the value of the current scalar field for the current time step on that point. Probe dialog box - Plot: allows the user to pick a point and automatically generate a plot of the scalar field value on that point as a function of time. Tools Toolbar Tools toolbar PAM-RTM USER'S GUIDE Presentation of the User Interface PAM-RTM 2014 © 2014 ESI Group 23 USER’S GUIDE & TUTORIALS (released: Apr-14) There is only one tool currently available in this toolbar: the measure tool. Pushing this button opens the Measure dialog box, allowing the user to pick two arbitrary points on the mesh and get the distance between the points. Measure tool Model Explorer The model explorer displays information about open documents in a tree structure. The information displayed can be seen as a summary of open documents. Only the most useful information is displayed in the tree, depending on the type of simulation. Double-clicking an item in the tree most of the time pops up a dialog box to edit the parameters related to the selected item. For example, double-clicking a zone opens the Zone dialog box. Zone dialog box Right-clicking an item in the explorer will most probably popup a menu, depending on the item selected. In the following picture, the user right-clicked on the Materials item. PAM-RTM USER'S GUIDE Presentation of the User Interface USER’S GUIDE & TUTORIALS (released: Apr-14) 24 PAM-RTM 2014 © 2014 ESI Group Right-click in the explorer window Message Pane The message pane is used to display messages to the user. A tree structure is used. For example, the Selection->Info Detailed command prints the following. Message pane PAM-RTM USER'S GUIDE Presentation of the User Interface PAM-RTM 2014 © 2014 ESI Group 25 USER’S GUIDE & TUTORIALS (released: Apr-14) FILE MENU File > New This is used to create a new simulation project. The supported simulation types are: - RTM: classical isothermal closed mold RTM. - VARI: Vacuum Assisted Resin Infusion. Isothermal injection under deformable plastic film. The thickness and permeability change of the fiber reinforcement is taken into account. - Heated RTM: non-isothermal RTM. Heat exchanges between resin, fiber reinforcement and mold is taken into account. The effect of resin polymerization on viscosity and heat generation can also be taken into account. - Preheating: heating of the mold and fiber reinforcement before filling. The possibly non-uniform temperature distribution at the end of preheating can be used to initialize Heated RTM simulation. - Curing: post-filling resin cure. By default, assumes that the cavity is completely filled and the initial temperature and degree of cure is uniform. Otherwise the results of the Heated RTM simulation (filling factor, temperature, degree of cure) can be used to initialize the curing simulation. - Compression RTM: simulates a process in which some amount of resin is injected first with a cavity thickness slightly higher than the targeted part thickness. This is done in order to facilitate impregnation since the permeability is higher. Once that amount of resin has been injected, the part is not completely filled yet. The inlet is closed, and the remaining dry areas are filled by a flow induced by compression of the preform. The compression direction can be normal to the part, or in a specified direction. This simulation is based on a 2.5D modeling where only the pseudo thickness of the shell element varies. Thus only meshes of triangles are supported. - Presimulation: this simulation allows a first approximation of the filling time and flow behavior without solving Darcy’s equation. That’s why it is very fast. However it works only with constant flow rate injection. - PAM-QUIKFORM: draping analysis of fiber reinforcements (bi-directional fabrics and unidirectional). PAM-RTM USER'S GUIDE File Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 26 PAM-RTM 2014 © 2014 ESI Group New Simulation dialog box File > Open This is used to open a project file (.dtf) or a mesh file. Most of the time this command is used to open a .dtf file, which contains the PAM-RTM™ simulation parameters as well as links to external files such as mesh files. It can also be used to open directly a mesh file. In that case a default RTM simulation is automatically associated to the opened mesh file. The option PAM-RTM Parallel (.unf) is to be used for post-processing of results generated by the new high performance parallel solver introduced in PAM-RTM™ 2010. Note: · The .unf format is intended for post-processing only. All the pre-processing functionalities of the PAM-RTM GUI, such as creation of groups, specification of material orientations, etc., will be non-functional if such a document is loaded. The supported mesh file formats are: - PAM-SYSTEM - I-DEAS Universal - PATRAN Neutral - NASTRAN Bulk PAM-RTM USER'S GUIDE File Menu PAM-RTM 2014 © 2014 ESI Group 27 USER’S GUIDE & TUTORIALS (released: Apr-14) File Open dialog box File > Close Closes the active document. If some modifications were done, the user is prompted to save the file before closing. File > Save Saves the .dtf file (simulation parameters) and the mesh file (.unv) in the directory where the .dtf file was opened. For example, if file c:\rtm_tests\test.dtf was opened, when the File->Save command is used, the file c:\rtm_tests\test.dtf will be overwritten and the associated mesh file c:\rtm_tests\test.unv will be generated. PAM-RTM USER'S GUIDE File Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 28 PAM-RTM 2014 © 2014 ESI Group File > Save As Prompts the user to specify a new name and directory for the project. For example, if c:\rtm_tests\test_2.dtf is chosen, the current simulation parameters will be saved in c:\rtm_tests\test_2.dtf and an associated mesh file c:\rtm_tests\test_2.unv will be generated. File > Import > Mesh This is the command to use after a File->New, to import in the current document the mesh to use for the simulation. In some rare situations you could use this command to load many meshes in the current document, then merge them with Mesh->Cleanup>Merge Coincident Nodes. See File->Open for the supported mesh file formats. File > Import > Scalar Fields This command is used to import scalar fields (simulation results) into the currently active PAM-RTM™ document for post-processing. These are the available file formats for scalar fields: - I-DEAS Universal (extension: .unv) - PAM-RTM Scalar Field (extension: .sf) - PAM-RTM Filling Compact (extension: .fil) - PAM-RTM Flow Front (extension: .front) - Velocity Components Vx Vy Vz (I-DEAS format, extension .unv) The PAM-RTM Filling Compact file contains the filling result of a PAM-RTM™ simulation. The size of this file is much smaller than the same scalar field saved in a more general format like I-DEAS Universal. The PAM-RTM Flow Front file contains the flow front position in time. This is the “raw” flow front position (not smoothed). It is made of line segments that define the saturated domain. The flow front position can be displayed on top of any scalar field in PAM-RTM™. This is useful to analyze, for example, temperature results. Since PAM-RTM™ 2008, it is possible to display a vector field on top of a scalar field. This is generally used to display the resin velocity vector field on top of a pressure or temperature field, for instance. However any 3 components vector field could be displayed, as long as the 3 components are imported together with File->Import->Scalar Fields->Velocity Components. In general the user doesn’t have to use this command, as the velocity components are imported automatically with the Reload Results button in the Results Toolbar, if the Save Velocity option was checked in the Numerical Parameters. PAM-RTM USER'S GUIDE File Menu PAM-RTM 2014 © 2014 ESI Group 29 USER’S GUIDE & TUTORIALS (released: Apr-14) Note: · The preferred way to load simulation results in PAM-RTM™ is to use the button in the Results Toolbar. File > Import > Draping Results This menu is used to import draping analysis results files in the active document. Draping results are a set of meshes that define plies geometry (one mesh for each ply). Depending on the software that generated the laminate plies, material properties like fiber directions and thickness can be defined on each finite element of a ply. For example, the result of a PAM-FORM™ simulation gives the fiber orientations and thickness on each element. However a PAM-QUIKFORM™ simulation gives only the fiber directions, not the thickness. These are the available interfaces to import draping results in PAM-RTM™: - PAM-FORM - PAM-QUIKFORM - PATRAN Laminate Modeler - FiberSIM XML All these interfaces support local fiber directions specified on each element of each ply. The PAM-FORM interface reads a PAM-FORM™ results file (extension .dsy). A PAM-FORM™ results file normally contains many states. PAM-RTM™ assumes that it is only the last state that is interesting in the context of RTM simulation, so it loads in memory only the last state of the PAM-FORM™ simulation. There are two possibilities to import PAM-QUIKFORM™ results. In case the PAMQUIKFORM simulation was created and run in PAM-RTM (File->New->PAMQUIKFORM), it is possible to import the PAM-QUIKFORM .dtf file, in which case higher level information such as materials used in the laminate definition is available. Otherwise it is also possible to import only the PAM-QUIKFORM generated mesh files (.ps, PAM-SYSTEM format). In that case, the user will have to associate materials to imported meshes by re-defining the laminate, if calculation of local permeability is needed. The PATRAN Laminate Modeler interface reads a .fmd file, which contains a list of filenames that define the laminate. Each ply is a NASTRAN file with a special definition of the PCOMP section that allows the specification of 2 fiber directions on each element. One PCOMP section is specified for each element and each PCOMP section refers to 2 layers of UD. The FiberSIM interface is used to import ply data generated by the FiberSIM software, in a special XML format. PAM-RTM USER'S GUIDE File Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 30 PAM-RTM 2014 © 2014 ESI Group File > Export > Mesh This command is used to export the current mesh in one of the supported formats: - PAM-SYSTEM - I-DEAS Universal - PATRAN Neutral File > Export > PAM-RTM Scalar Field This is used to export the currently displayed scalar field in a PAM-RTM™ specific file format. This is used most of the time in the context of local permeability calculation, to export the k1.sf, k2.sf, porosity.sf and thickness.sf files needed to initialize a calculation that takes into account local permeability. File > Clear > Scalar Fields Clears from memory all the scalar fields that have been imported in the current document with the command File->Import->Scalar Fields or loaded with the button. File > Clear >Laminate Clears from memory all the plies meshes that have been loaded by using File->Import>Laminate. File > Save Image Saves the active 3D graphics window in one of the supported graphics file formats: - PNG - GIF - TIFF - JPEG File > Generate AVI Generates an animation file (.avi) from the currently visualized scalar field. The resulting AVI file can be visualized in Windows Media Player or integrated in PowerPoint presentations. When the command is selected, the following dialog box pops-up, allowing the user to specify the cycle time, which is the time to display all the frames in the AVI file. The end delay is used to have the last frame displayed for some time. This can be useful for presentations. PAM-RTM USER'S GUIDE File Menu PAM-RTM 2014 © 2014 ESI Group 31 USER’S GUIDE & TUTORIALS (released: Apr-14) AVI Generation Then the user is asked to specify the name of the generated AVI file from the standard Windows file selection dialog. Finally another dialog box pops up to select the “codec” to compress frames in the AVI file. This dialog box lists all the available codecs on the user machine. Since this list depends on other software installed on the machine, it is difficult to recommend the best codec. The Cinepak codec by Radius seems to be available on most machines and has given good results. However it is recommended to download from the internet the XviD MPEG-4 codec, which is open source and free. The Full Frames codec should be avoided as it generates huge files. Selection of codec Note: · Introduced in PAM-RTM™ 2008, the generated AVI can now take into account the Proportional animation option. File > Print Prints the active 3D graphics window. File > Print Preview Gives a preview of the print command in the standard Windows print preview window. File > Print Setup Opens the standard Windows dialog box to configure printing. PAM-RTM USER'S GUIDE File Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 32 PAM-RTM 2014 © 2014 ESI Group SELECTION MENU Selection Filter There are three types of geometrical entities that can be selected in PAM-RTM™: nodes, finite element faces, and finite elements. The selection filter is used to specify the type of entity to select. For example, if you want to pick some elements with the mouse, you have to set the selection filter to Element. If you want to select all the elements in a zone specified with an ID, you have to set the selection filter to Element before using the Selection->Zone ID command. The usual way to set the selection filter is using the Display toolbar. The Selection->Node, Selection->Face, and Selection>Element commands can also be used. A check mark is shown besides the currently active filter. Selection filter in the Display toolbar Selection filter in the Selection menu Selection > Pick Normal Vector The Pick Normal Vector command is useful to select entities on the same planar surface (i.e. entities that have the same normal vector) in a single operation. For example, in the following image, all the faces in red were selected in a single click, while selection by area would have required many operations. When the Pick Normal Vector command is used, a dialog box pops up to prompt the user for a tolerance on the angle between two adjacent faces (angle between the 2 normal vectors). This is useful when the surface to select is not perfectly planar. Note that nodes, faces and elements can be selected using this approach. When the selection filter is Nodes, all the nodes of all the faces that have the specified normal vector are selected. PAM-RTM USER'S GUIDE Selection Menu PAM-RTM 2014 © 2014 ESI Group 33 USER’S GUIDE & TUTORIALS (released: Apr-14) Selection of faces with Pick Normal Vector Tolerance angle for Pick Normal Vector Selection > Pick Normal Vector and Zone This command is basically the same as the previous one, except that it adds as a selection filter the zone ID of the face used to define the normal vector. Selection > Pick Zone This command allows selection of all the nodes, all the faces or all the elements in a zone picked by the user with the mouse. The user is first prompted to pick a face in the zone to select. Then all the entities are selected based on the current selection filter. PAM-RTM USER'S GUIDE Selection Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 34 PAM-RTM 2014 © 2014 ESI Group Selection > Pick Boundary This command is useful to quickly select all the nodes on a boundary. The user is first prompted to pick the initial node that will be used in the algorithm to determine the boundary based on the neighbor elements of this node. Currently only boundary nodes, not elements, can be selected this way. Selection -> Pick Boundary Selection > Pick Free Edge With this command, the user can select with a single click all the nodes along one side of the part. The identification of a part’s side is done neighbor to neighbor starting from the picked node. The user is prompted to enter a tolerance to stop the propagation when the angle between two elements is larger than the tolerance value. Typically a tolerance value of 30 degrees could be used, to allow selection on a curved side and stop selection when a sharp corner is reached. PAM-RTM USER'S GUIDE Selection Menu PAM-RTM 2014 © 2014 ESI Group 35 USER’S GUIDE & TUTORIALS (released: Apr-14) Selection > Zone ID When the zone ID of the entities to select is known, the user can type it directly in the dialog box that pops up when the Selection -> Zone ID command is used. It is also possible to enter two values to specify a range. In the following image, the user enters 1 and 7 to select all the elements of all the zones in the range 1 to 7. PAM-RTM USER'S GUIDE Selection Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 36 PAM-RTM 2014 © 2014 ESI Group Selection with zone ID Selection > Entity ID This command is used to select an entity based on its ID. For example, it is possible to select the node with ID = 999 by entering this value in the selection dialog box. It is also possible to select all the nodes with IDs in the range 0 to 999 by entering the string “0 999” in the text field. This is the same behavior as Selection->Zone ID. Selection > Bounding Box This command opens a dialog box in which the user can specify the (xmin, ymin, zmin) and (xmax, ymax, zmax) coordinates of a bounding box. All the entities that fit in this bounding box are selected. For a face or an element, as soon as a node is inside the bounding box, the entity is selected. Selection with bounding box PAM-RTM USER'S GUIDE Selection Menu PAM-RTM 2014 © 2014 ESI Group 37 USER’S GUIDE & TUTORIALS (released: Apr-14) Selection > Select All Selects all the entities based on the current selection filter. For example, if the selection filter is set to Nodes, all the nodes of the mesh are selected. Selection > Unselect All (filter) Unselects all the entities based on the current selection filter. For example, if the selection filter is set to Nodes, all the nodes are unselected. If faces or elements are selected, they stay selected. Selection > Unselect All (no filter) Completely clears the current selection (nodes, faces and elements) regardless of the in the selection filter. You can also use the CTRL-U keyboard shortcut or this button Selection toolbar to call this command. Selection > Set Scalar Field Value If you are currently visualizing a scalar field such as porosity or thickness, you can use this command to modify the scalar field values on the selected nodes or elements. This is sometimes useful to correct scalar fields after a Compute Local Permeability, when the mapping results are not very good because of complex geometry. The corrected scalar fields can be exported with File->Export->PAM-RTM Scalar Field. Selection > Info Summary Displays in the message window information about the current selection. The total number of nodes, faces and elements is displayed. Selection > Info Detailed Displays in the message window the details of the current selection. The ID of each selected entity is displayed. For example: For selected faces, e means element ID, f means face index of the element (solid elements only), z means zone ID, and n is the connectivity of the element. For selected nodes, n means node ID, g is group ID (if the node is part of a group), and the (x, y, z) coordinates of the node are displayed. PAM-RTM USER'S GUIDE Selection Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 38 PAM-RTM 2014 © 2014 ESI Group GROUPS MENU Groups of nodes or faces are created in PAM-RTM to be used as boundary conditions. Groups > Create Creates a new group with the currently selected entities. If nodes are currently selected, a new group of nodes is created. If faces are selected, a new group of faces is created. It is not possible to create a group of elements in PAM-RTM. The ID of the new group is automatically assigned by PAM-RTM based on the largest ID of the groups currently defined. If the largest group ID is 99, the new group will have ID = 100. It is not possible to change the ID of a group after it has been created. It is not possible to have nodes and faces in the same group. Groups > Add To This command is used to add nodes or faces to an existing group. The procedure is to select first some nodes or faces, then call the Groups->Add To command, and finally pick a node or face which is part of the group you want to modify. Groups > Remove From The procedure is to first select some nodes or faces, then call the Groups->Remove From command. The selected entities will be removed from all the groups they belong to. This means that if a node, for example, was part of 2 groups, it will be removed from the 2 groups. Groups > Change ID This command allows modification of a group ID. It asks the user the current ID of the group, and its new ID. If the specified new ID is already used, an error message is displayed. Groups > Contact Interface This command is used to create a special group that is currently used only for thermal contact resistance boundary condition. The elements are disconnected on the interface. This can be verified with the command View->Outline->Free Edges. A contact interface can only be created on the interface between two zones. The selection of nodes must be done with care. As shown in the following image, the two end points must not be selected. On a 3D mesh, it is recommended to work with a selection of faces. PAM-RTM USER'S GUIDE Groups Menu PAM-RTM 2014 © 2014 ESI Group 39 USER’S GUIDE & TUTORIALS (released: Apr-14) Nodes selection for contact interface Free edges after creation of contact interface Groups > Mold/Cavity Interface Automatically disconnects the elements on the mold/cavity interface for the whole mesh. The material type assigned elements through zones is used. Material type solid defines the mold area, and reinforcement the cavity area. A group of faces is automatically created, that can be referred by a contact resistance boundary condition. The following pictures show a cross section of a part with a metallic mold and insert. The first picture shows the solid material area (mold + insert), the second picture shows the reinforcement area, and the third picture shows the interface created by this command. PAM-RTM USER'S GUIDE Groups Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 40 Solid material area (mold + insert) Reinforcement material area Interface created PAM-RTM USER'S GUIDE Groups Menu PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 41 USER’S GUIDE & TUTORIALS (released: Apr-14) Groups > Nodes to Faces Convert a group of nodes to a group of faces. PAM-RTM prompts the user for the group ID to convert. Enter –1 to convert all groups. Groups > Faces to Nodes Convert a group of faces (for solid elements) or edges (for shell elements) to a group of nodes. PAM-RTM prompts the user for the group ID to convert. Enter –1 to convert all groups. This command is useful for example when you import a mesh generated in IDEAS which contains groups of edges. PAM-RTM reads the group of edges from the IDEAS file, but these groups can’t be visualized or modified with the user interface. In such a case, this command should be used to convert all groups of edges to nodes. Groups > Delete (Pick) To delete a group, the user first calls this command, then picks a node or face in the group to delete. Groups > Delete (ID) Another way to delete a group is by entering its ID. Enter –1 to delete all groups. Groups > Info Summary Displays in the message window a short summary of the currently available groups. The ID of the group is listed, together with the total number of nodes or faces in the group. Groups > Info Detailed Lists in the message window all the node IDs and face IDs of all the groups. PAM-RTM USER'S GUIDE Groups Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 42 PAM-RTM 2014 © 2014 ESI Group MESH MENU Commands in the Mesh menu are used to make some modifications to a mesh, but most importantly to specify material orientations. Mesh > Remesh > Injection Point This command is used to create a hole in a shell mesh that can be used as an injection point. A group is automatically created within the nodes around the hole. The following image shows the Mesh Injection Point dialog box, together with the points that were picked for Center (A) and Radius (B). Creation of a hole and a group PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 43 USER’S GUIDE & TUTORIALS (released: Apr-14) Mesh around the hole Mesh > Remesh > Runner This command is used to create layers of thin elements that can be used to simulate runners or edge effects. The remeshed areas are most of the time on the part boundary, but they can also be internal to simulate special injection systems (for example injection tubes placed on top of the part). A distinct zone ID is automatically assigned to the elements in the remeshed zones. You will most probably need the measure tool to use this command effectively. In the following image, a runner is created on the complete boundary of a rectangular part. To pick the full boundary, push the Boundary button, then pick any node on the boundary. The boundary is highlighted. Then you have to specify the size of elements along the path. The runner can be seen as a cylinder placed on top of the part. That’s why it makes sense to talk about the runner radius. Specify the runner radius and the number of element layers you want on the runner radius. Use the measure tool to estimate the size of elements along the path and the runner radius. In this example the size of elements along the path was set to 0.01 m, the runner radius is 0.02 m and the number of layers on the radius is 2, which leads to elements with a good aspect ratio. As shown in the resulting mesh image, the runner is not a perfect straight line. However this should be good enough to simulate runners in PAM-RTM. PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 44 PAM-RTM 2014 © 2014 ESI Group Creation of a runner on the boundary It is also possible to create internal (not located on the boundary) free paths. Push the Free button, and then pick a sequence of nodes or points to define the path. The following images show how a branch like injection system can be created. First push the Free button, then pick nodes A and B. Enter the size parameters, then push the Apply button. Repeat the same procedure for the lines C-D and E-F. Creation of a branch like injection system PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 45 USER’S GUIDE & TUTORIALS (released: Apr-14) Mesh > Orientations > K1 The Mesh->Orientations->K1 and Mesh->Orientations->K2 commands are used to set the current working direction. For example, a command like Set K Orthogonal needs to know if the direction to make orthogonal is K1 or K2. A check mark is displayed beside the current working direction. Mesh > Orientations > Set Vectors This command is used to set the direction vectors K1 and K2 by entering the 3 coordinates of vectors specified in the global coordinate system. After specifying the coordinates of K1 or K2, push the Set K1 or Set K2 button to apply the appropriate vector. The Set Vector command works on the currently selected faces or elements. Mesh > Orientations > Project Vectors This command is the same as Set Vectors except that it does an orthogonal projection of the specified vectors on the selected elements. Dialog box used by Set Vectors and Project Vectors Mesh > Orientations > Set K from Selected Nodes This command is used to specify material orientations in curved regions for which permeability directions can be described by a simple piecewise linear curve. For example, in the following image, K1 was specified by projecting the elements on the curve defined by the selected nodes. The tangent vector of the curve at the point of projection defines the K1 direction. Depending on the current working direction, K1 or K2 will be specified. PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 46 PAM-RTM 2014 © 2014 ESI Group Setting material orientations in a curved region The procedure to use this command is the following: - Set the working direction (K1 or K2). - Select faces or elements on which you want to specify the direction. - Select nodes to define a piecewise linear curve. Nodes must be selected in a consistent order. For example in the previous image, nodes could be selected from bottom-left to top-right, or from top-right to bottom-left. - Execute the Mesh->Orientations->Set K from Selected Nodes command. - Verify the direction vectors with View->Orientations->K1 Only or View- >Orientations->K2 Only. Mesh > Orientations > Set K Orthogonal This sets the orientation vectors in the current working direction as orthogonal to the other direction. For example, if the current working direction is K2 and this command is executed, the K2 direction of the selected elements will be made orthogonal to K1. Of course, in this example, K1 must be defined first. Mesh > Orientations > Align Plies This command is used to make material orientations consistent in plies. For example, after importing PAM-QUIKFORM plies, some direction vectors could be pointing in the X+ direction while other vectors in the same ply could be pointing in the Xdirection. The goal of this command is to have all the elements in a ply oriented in the same global direction. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 47 USER’S GUIDE & TUTORIALS (released: Apr-14) The algorithm currently implemented takes the first element of a ply and makes the directions consistent on the ply from neighbor to neighbor. This means that there is a risk that from ply to ply the directions could not be consistent. The user should always check the orientations on each ply after running this command. If a problem is found on a ply, the orientations on this ply can easily be reversed by selecting all the elements of the ply with Selection->Select All, then by reversing the orientations with Mesh -> Orientations->Reverse. Mesh > Orientations > Reverse This command reverses the current direction (K1 or K2) of the selected elements or faces. For example, if the current working direction is K1 and the command is executed on a set of elements with K1 pointing in the +X direction, the K1 direction will be reversed to -X. Mesh > Orientations > Project on Skin This command is used to project the orientation of an imported draping result on the mesh. It searches for each element in the mesh the closest element in the draping result and sets the direction K1 and K2 found on the draping result element on the mesh element. Mesh > Orientations > Interpolate This command works with two imported draping results, called skins. It will make an interpolation of the directions on each skin for the mesh. The algorithm works that way: For each element of the mesh and each element of the skin, the coordinates of the centers of gravity (COG) are computed. If the distance between COG is inferior to the tolerance, it will try to project the cog on the skin element. PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 48 PAM-RTM 2014 © 2014 ESI Group If no valid projection of the COG is found, the closest COG of the elements of skin mesh will be found, and the element will be selected. For each skin, the direction of the weft and warp projection element will be saved, and the weft and warp direction of the element of the mesh to orient will be an interpolation of these two directions. The used algorithm is the following. Search of the 2D elements the COG of which is close to the element E COG from a distance lower than a value D given by the user. Projection of the COG of the element E on the medium plane of the retained 2D elements. This projection is performed along the medium plane Selection of the 2D skin elements for which the projections are inside those 2D elements. Search of the closest 2D skin element e of the element E Definition of the element e material orientation on the element Ei: (WrEi_inner, Wf Ei_inner, ZEi_inner) PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 49 USER’S GUIDE & TUTORIALS (released: Apr-14) Then the interpolation formula is Interpolation formula : WrEi = dEi_outer / (dEi_inner + dEi_outer) × WrEi_inner + dEi_inner / (d Ei_inner + dEi_outer) × WrEi_outer WfEi = dEi_outer / (dEi_inner + dEi_outer) × WfEi_inner + dEi_inner / (d Ei_inner + dEi_outer) × WfEi_outer ZEi = WrEi Λ WfEi Where: - Wr and Wf are Weft and Warp directions, - Z normal vector, - Ei_outer is related to the outer skin and Ei_inner is related to the inner skin. The function is used with this dialog box where the user can define or not define if the box is not checked: - Path to the inner skin mesh file - Path to the outer skin mesh file, - Path to the output mesh in .unv format, - Path to the log file, - Tolerance value (mandatory), - Path to the SAMCEF file, - Number of the first frame in SAMCEF frame file. PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 50 PAM-RTM 2014 © 2014 ESI Group If the box for the inner and outer skin are not provided the interpolation will be made with draping results that would have been imported with the function Mesh->import>draping results. It will work only in the case when two draping results are already loaded. Otherwise an error message will be displayed. If the box for the output mesh is not checked, the mesh will not be automatically exported. The user will have to export the mesh with Mesh->export or save the data. If the box for the log file is not checked, no log file is written. If the box for the SAMCEF frame file is not checked, this file is not exported. Every path selection will be made with windows explorer dialog box. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 51 USER’S GUIDE & TUTORIALS (released: Apr-14) The user can follow the interpolation with a dialog box indicating the percentage made at any time. It is possible to stop calculation at any time by clicking on Cancel in this dialog box. When interpolation is finished, a projection scalar field is displayed. The code for projection scalar field is: - 1: projection worked on both skins, - 2: projection didn’t work on lower skin, the closest element is chosen, - 3: projection didn’t work on upper skin, - 4: projection didn’t work on both skins. Below are showed one case where projection where some elements do not have a valid projection. Trapezium volume mesh and skins to project PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 52 PAM-RTM 2014 © 2014 ESI Group Trapezium projection results The orientation can be displayed with the menu View->Orientation. The .log file contains the following information: - CPU time for the interpolation of the distance, - Name of the exported files (.unv and .dat) - For each element of the initial mesh: · Number of element · Number of the projection element on inner/outer skin or closest element id projection didn’t work · Distance of projection · Weft/warp vector for inner/outer skin · Weft/warp vector for the element. Examples of the content of the .log file are shown below in the cases where both projections worked and only the projection on outer skin worked. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 53 USER’S GUIDE & TUTORIALS (released: Apr-14) SAMCEF frame file contains for each element weft and warp vector using following format: Frame number Warp interpolated vector coordinates Weft interpolated vector coordinates Element number Frame number PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 54 PAM-RTM 2014 © 2014 ESI Group Introduced in PAM-RTM 2009 is a new optimized version of the method described above. To enable the optimized version, simply select use optimized version. The optimized version uses a completely different algorithm for the projection of the solid elements on the surface meshes. This algorithm is much faster but a little less accurate, so the non-optimized version should be used when accuracy is of primary concern compared to CPU time. However speedups of 30 were obtained with the optimized version, which makes it the version of choice for meshes of millions of elements. To get the best performance from this optimized version, the size of the surface elements should be at least 2 times smaller than the solid elements. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 55 USER’S GUIDE & TUTORIALS (released: Apr-14) Mesh > Orientations > Map Draping Results This command is used to project a stack of plies that have been imported with the command File->Import->Draping Results, on the mesh used for the injection simulation (the mesh that was loaded in PAM-RTM™ with the command File->Open or File>Import). This is a CPU intensive geometrical calculation that tries to match elements of the injection mesh with elements in plies. The final goal is the calculation of the average local permeability on the injection mesh by taking into account the local fiber orientations in each ply. Basically, what the algorithm does is the following: - For each element of the injection mesh · Calculate the center of gravity (C) of the injection mesh element. · Define a ray R starting from C, with the direction of the normal vector of the injection mesh element. · For each ply mesh Calculate the intersection of R with all the elements of the ply mesh If an intersection is found within the normal max distance value, record the mapping of the element of the ply mesh with the element of the injection mesh. This is an exhaustive search through all the elements of all the plies. The Map Draping Results command can work on the full injection mesh, or on the currently selected elements. If the current selection is empty, mapping is done on the full injection mesh. Otherwise, PAM-RTM™ asks the user if he wants to do the mapping on the selected elements only, or the full injection mesh. PAM-RTM™ then prompts the user for the normal max distance parameter, as shown in the following dialog box: Mapping tolerance PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) - 56 PAM-RTM 2014 © 2014 ESI Group Normal max distance. Unit: length. center of gravity d Valid projection discarded because d >max normal distance The max normal distance is used to discard elements that have a valid projection, but the distance between the center of gravity of the injection element and the projected point is larger than the specified tolerance. This is useful in case of ribbed parts. When the mapping calculation is done, it is always a good idea to verify the validity of the mapping with the Nb_Plies scalar field. This scalar field is automatically generated by PAM-RTM™ after a Map Draping Results calculation. It shows the number of plies covering each element of the injection mesh. For example, if you drape 4 plies that cover completely the surface to drape, you should have Nb_Plies = 4 everywhere. If you find that some elements have different values, it means there was a problem with the mapping, and maybe you need to change the max normal distance. Mesh > Orientations > Compute Local Permeability on Shells Before we describe the options to calculate the local permeability of a sheared fabric, some definitions are necessary. A very important thing to understand is that when you visualize material orientations in PAM-RTM™ with the View->Orientations->K1 or View->Orientations->K2 commands, these orientations can have a different meaning depending on the context. For example, when you visualize orientations on a ply imported with the PAM-FORM interface, the orientations should be seen as fiber directions, not permeability directions. However if you use View->Orientations->K1 on the injection mesh after a Compute Local Permeability, the vectors you see are principal directions of the permeability tensor, not fiber directions. In the following text, we will refer to the direction visualized with View->Orientationsin the context of fiber directions as f1. The f1 direction is also defined as the warp direction for fabrics. The f2 direction is the weft direction for fabrics. >K1 The shear angle α is defined as shown in the next figure: it is the angle between the weft direction and the direction orthogonal to the warp. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 57 USER’S GUIDE & TUTORIALS (released: Apr-14) Definition of the shear angle α When a fabric is sheared, the principal directions of the permeability tensor change as a function of the shear angle α. The principal permeability direction K1 is defined with an angle β relative to the warp direction. Rotation of the K1 direction as a function of the shear angle α In general, a laminate is made of many plies with different thickness and material properties. A typical laminate made of many layers of different thickness and permeability PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 58 PAM-RTM 2014 © 2014 ESI Group The average permeability calculation takes into account the thickness of each layer: n ∑k h i i kavg = i =1 n ∑h i i =1 Since the permeability of each layer is actually a tensor, the permeability tensor of each layer is transformed in the referential given by the K1 and K2 directions of the first ply. The resulting non-diagonal tensor is then diagonalized and the final principal directions of the laminate are the eigenvectors of the non-diagonal tensor. The local permeability values k1 and k2 are the eigenvalues. There are two ways to use the Compute Local Permeability command. The first one simply computes the average permeability, porosity and total thickness of a laminate material (found in the Materials folder of the document tree), and assigns these values to the current selection, or the whole mesh if nothing is selected. It uses the currently defined orientations on the mesh as the zero degree referential. The other approach uses the mapping computed by the Map Draping Results command to calculate the average local permeability of deformed plies. In that context, a laminate material still has to be defined by the user in order to link material properties to the imported plies. The number of layers of this laminate must match the number of imported plies. For example, if 4 draped plies were imported, a laminate material made of 4 layers must be defined. This is because PAM-RTM™ needs to know the type of reinforcement and permeability model associated to each layer. When the Mesh->Orientations->Compute Local Permeability command is called, PAMRTM™ opens the following dialog box. If draped plies, such as PAM-QUIKFORM results imported with File>Import>Draping Results, are to be used for the average permeability calculation, the user checks the use imported plies option. Otherwise, if that option is not checked, it means that one of the laminate materials currently defined will be used. The laminate combo lists the available laminate materials. In case sheared fabrics such as PAM-QUIKFORM™ results are used, it is also necessary to specify the permeability model for sheared fabrics. Four models are currently supported and explained below: unidirectional, isotropic woven fabric, general woven fabric, and Demaria. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 59 USER’S GUIDE & TUTORIALS (released: Apr-14) Available models to compute local permeability of fabrics UD Model When a layer is associated to a UD (unidirectional) reinforcement, the local K1 principal permeability direction is automatically set in the same direction as the f1 fiber direction. The f2 direction is completely ignored (it is a UD, so the f2 direction is meaningless), and K2 is made orthogonal to K1. The permeability values assigned in the K1 and K2 directions are directly the values specified in the Reinforcement associated to each layer, without any local modification based on shearing. Referring to the figure Rotation of the K1 direction as a function of the shear angle α, the K1 direction is given for this model by β=0. Principal permeability K1 for unidirectional PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 60 PAM-RTM 2014 © 2014 ESI Group Isotropic Woven Fabric Model With this model, which is valid only for fabrics with initially isotropic permeability (permeability of the fabric before shearing is isotropic), the principal permeability direction K1 is calculated as the bisector of the angle between the warp and weft (θ1 = θ2 in the following figure). Permeability directions calculated with the isotropic woven fabric model Referring again to figure Rotation of the K1 direction as a function of the shear angle α, the angle β for this model is given by : β =45−α 2 The local fiber content (vf) is calculated from the shear angle (α) and the initial fiber content of the ply, before deformation (vf0) : v f = v f0 cosα The local permeability values in the principal directions are then computed using the permeability curves function of the fiber content specified in the Fabric associated to the ply (we call these curves U1 and U2 here) and an internal model that modifies these values as a function of the shear angle (M1 and M2) : k1=U1(v f )*M1(α) k2 =U 2(v f )*M 2(α) This means that to use this model, the user should ideally have access to experimental curves giving the permeability as a function of the fiber content. These curves are entered in the Permeability K1 and Permeability K2 fields of the fabric editor (next figure). The initial porosity required to calculate the local fiber content is specified for each layer of the laminate. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 61 USER’S GUIDE & TUTORIALS (released: Apr-14) Specification of the permeability curves as a function of the fiber content in the Fabric Properties dialog Woven Fabric Model This empirical model uses the functions specified in the Sheared Permeability K1, K2, K3 and Sheared Rotation Angle (β) fields of the fabric editor. These are functions of the shear angle and initial fiber content: k1= f(α,v f0) k2 = f(α,v f0) k3 = f(α,v f0) β = f(α,v f0) The definition of the rotation angle β is the one shown in figure Rotation of the K1 direction as a function of the shear angle α. It is important to note that to calculate the K1 direction with the angle β, PAM-RTM™ constructs a right handed local coordinate system on an element of a ply with the f1 direction, the normal vector of the element, and the direction orthogonal to f1 and the normal vector (f1o). If the user notices that K1 is not rotated in the expected direction, he should verify normal vectors in each ply with View->Normal Vector, and then use the Mesh->Cleanup->Reverse Normals command if necessary to reverse the normal vectors of a ply. PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 62 PAM-RTM 2014 © 2014 ESI Group n f1o K1 β β f1 f1o f1 n K1 The effect of the normal vector on the K1 direction The local fiber content (vf) is calculated from the shear angle (α) and the initial fiber content of the ply, before deformation (vf0): v f = v f0 cosα As an application example of the first approach (the one that works directly on a laminate without draping results), suppose you have a mesh already oriented and you want to rotate the orientations by 45 degrees. You could define a single layer laminate material, set the orientation angle of that layer to 45 degrees, run the Compute Local Permeability command and select the one layer laminate in the laminate dropdown list. Demaria Model The reference for this model is: Demaria C, Ruiz E, Trochu F. In-plane anisotropic permeability characterization of deformed woven fabrics by unidirectional injection. Part II: Prediction model and numerical simulations. Polymer Composites, December 2007. This model assumes that the principal permeabilities in the two principal directions can be expressed as follows: ( ) K1, 2 (α ) = K1, 2f (α )Fgeo (α ) = K1, 2 α = 0° Fv f (α )Fgeo (α ) v ( ) Only the unsheared permeabilities K1, 2 α = 0° are needed to use this model. The Fv f (α ) term is derived from Kozeny-Carman, and the Fgeo (α ) term from the geometrical analysis of the deformation of a unit cell. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 63 ( USER’S GUIDE & TUTORIALS (released: Apr-14) ) The K1, 2 α = 0° permeabilities are simply the Permeability K1 and Permeability K2 parameters found in the General tab of the Fabric Properties dialog. The parameter beta angle is available in the Compute Local Permeability dialog to specify the initial permeability angle with respect to the first fiber direction. It is equivalent to the angle β of the woven fabric model. This model has been validated experimentally on a woven fabric, and should be applicable to any woven fabric. The current implementation has an important limitation: the shear angle added to the initial permeability angle (beta angle) must remain in the X+Y+ quadrant, i.e. the final angle must be between zero and 90 degrees. For instance if the initial permeability angle is 60 degrees, a maximum negative shear deformation of 30 degrees is allowed, while a maximum positive shear deformation of 60 degrees is allowed. However it is better to stay away from these limits. The model will work better for instance with an initial permeability angle of 45 degrees and shear deformations in the range of +/- 30 degrees. Mesh > Orientations > Compute Local Permeability on Solids This command assumes that some orientations are already set on solid elements and represent fiber directions, potentially sheared (i.e. non-orthogonal). These orientations could have been transferred to the solid mesh with a command such as Project on Skin. This command is then used to compute from the draped fiber directions a permeability tensor on each solid element taking into account shearing. If some elements are selected, the command will only compute permeability of those elements. Otherwise it will use the whole mesh. When the command is launched, it opens a dialog box asking which draped permeability model to use. The options are: - Isotropic woven fabric (bisector) - Woven fabric The first option is the simple bisector model, which doesn’t need any material parameter. The second option makes use of the “sheared” parameters of the Advanced tab of the reinforcement dialog box. In that case, the zone ID of each element is used to get the associated reinforcement. There is actually a third option: if the zone refers to an unidirectional reinforcement, the first fiber direction f1 will be kept as is and used as permeability direction K1, then K2 PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 64 PAM-RTM 2014 © 2014 ESI Group will be made orthogonal to K1 in the plane of f1 and f2. The permeability value is directly the one specified on the reinforcement (in the General tab). The local porosity is also calculated by the command. The Use local permeability files and Use local porosity file options in the Numerical Parameters > Local Variables tab are automatically selected. Mesh > Orientations > Compute Local Permeability from Zones Starting with PAM-RTM™ 2010, it is now possible to assign laminate materials to zones. However the PAM-RTM™ solver cannot run a flow simulation directly on the laminate materials. Instead the solver reads the local permeability, local porosity and local thickness files generated by the PAM-RTM™ GUI (.sf files). First the user assigns some laminates to zones. Then he launches the Compute Local command to generate the local permeability, local porosity and local thickness data. These can be checked graphically by choosing the appropriate entry in the dropdown list of the main toolbar (K1 or Plies_Thickness for instance). The command will automatically turn on use local permeability files, use local porosity file and use local thickness file in the Local Variables tab of the Numerical Parameters. When the .dtf document will be saved, .sf files will be generated with names matching the .dtf name. This means the simulation is ready to run once the .dtf has been saved. Permeability from Zones Note that it is not mandatory to assign a laminate to every zone to use that command. Some zones could be linked to a simple reinforcement, while others could be linked to laminates. In a case involving race tracking for instance, the high permeability zone could be linked to a simple reinforcement. Mesh > Orientations > Compute Thickness from Skins The goal of that command is to calculate the distance between a shell mesh (the reference mesh) and the top and bottom surfaces of a solid, then generate a local thickness field for the reference mesh. The mesh that was loaded in the PAM-RTM™ GUI with File>Open or File>Import>Mesh is the reference mesh. The command uses the draped plies meshes currently loaded (one or two) as skin information. In case a single draped mesh is available, the reference mesh is seen as the bottom skin of a solid, and the draped ply is the top skin of the solid. In case 2 draped plies are available, these are seen as the top and bottom skins of the solid, and the reference mesh is the mid-surface of the solid. Below is an example where only the top surface of a solid was imported as a draped ply (File>Import>Draping Results>PAM-QUIKFORM). After running Compute Thickness from Skins, the Mapped_Thickness field is available in the dropdown list of the main toolbar. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 65 USER’S GUIDE & TUTORIALS (released: Apr-14) To use that thickness field in a filling calculation, the user has to export the field first with File>Export>PAM-RTM Scalar Field. Assuming the case is called x.dtf, the exported scalar field file would be called x_thickness.sf. Then the option use local thickness has to be checked in the Local Variables tab of the Numerical Parameters. Mesh > Orientations > Clear on Selection Removes any orientation specified on the currently selected elements. PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 66 PAM-RTM 2014 © 2014 ESI Group Mesh > Orientations > Clear All Removes any orientation specified on the whole mesh. Mesh > Transform > Set Zone ID This command is used to assign a different zone ID to the selected elements. This can be useful for example to create a runner (a zone with higher permeability). Selection of elements on the edge of a part to create a runner with Set Zone ID PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 67 USER’S GUIDE & TUTORIALS (released: Apr-14) Assignment of zone ID 99 to the selected elements Mesh > Transform > Offset Zone Ids Adds a user specified value to the zone ID of each zone. For example if 10 zones are currently defined and numbered from 1 to 10, an offset of 100 will renumber zones from 101 to 110. This is useful in the context of local permeability calculation from imported plies. If there is a conflict between the zone IDs of the injection mesh and the plies IDs, the user can simply offset the zone IDs of the injection mesh. Mesh > Transform > Extrude This command extrudes a mesh of shell elements to a mesh of solid elements. Triangle elements are transformed to 6-node prismatic elements, and 4-node quads are transformed to 8-node bricks. For simple extrusion, the user can specify the total thickness of the solid part and the number of layers. In that case all the layers will have the same thickness. A different zone ID is assigned to each layer so that it is easier later for the user to assign a different material to each layer. For more advanced extrusion, it is possible to select a laminate material, so that the thickness of each layer of the laminate is used as the thickness of each layer of the extruded mesh. This process is shown below. Assuming the user already created a PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 68 PAM-RTM 2014 © 2014 ESI Group laminate material and specified the thickness of each layer, he checks the Use laminate option and selects the laminate previously created in the dropdown list. Note that if Use laminate is checked, the Nb Layers and Total Thickness parameters are completely ignored. It is also possible to have the elements of the extruded mesh automatically oriented if the orientation from ply angles option is checked. This assumes the user has specified the angle of each ply of the laminate, and that orientations are defined on the shell mesh. The orientations of the shell mesh correspond to zero degree ply angle. The final orientations are obtained by rotating those orientations by each ply’s angle. Extrude dialog box PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 69 USER’S GUIDE & TUTORIALS (released: Apr-14) Definition of a 4 plies laminate, to be used for mesh extrusion. Notice the thickness of the 4th layer, much thinner. Shell mesh to be extruded PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 70 PAM-RTM 2014 © 2014 ESI Group Extruded 4 layers part Notice the top layer, much thinner. Linked to a material with a much higher permeability, it could be used as a flow enhancing layer, for VARTM simulation for instance. Mesh > Transform > Split Quads Splits the 4 nodes quad elements into triangles. Each quad is split in 4 triangles, the barycenter of the quad being used as the common node of the 4 triangles. This command is quite useful in PAM-RTM since quads are not allowed for filling simulations with Darcy. If the user has a mesh of quads that he would like to use for a PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 71 USER’S GUIDE & TUTORIALS (released: Apr-14) filling simulation, he can save a lot of time with this command instead of going back to his mesh generator. Mesh > Transform > Split Solid Elements The goal of this command is the same as the Split Quads command : since 6-node wedges and 8-node bricks are not allowed for PAM-RTM filling simulations with Darcy, this command can be used to split such elements into 4-nodes tetrahedra. Mesh > Transform > Scale Used to apply a scale factor to the nodes of a mesh. This is useful for example to convert a mesh in millimeters to meters, since meters are used in PAM-RTM. It is also possible to apply a scale factor to the pseudo-thickness of a shell mesh. Scale dialog box Mesh > Transform > Translate Applies a translation to all the nodes of a mesh, defined by the vector (DX, DY, DZ), in the global coordinate system. Translate dialog box PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 72 PAM-RTM 2014 © 2014 ESI Group Mesh > Transform > Rotate Rotates all the nodes of a mesh around a specified axis. The center of rotation can be specified. The rotation angle is entered in degrees. Rotate dialog box Mesh > Transform > Extract Shell from Solid Assuming some faces are selected on a solid mesh, this command generates a surface mesh from the selected faces. The current solid mesh in the document is replaced by the surface mesh. See images below. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 73 USER’S GUIDE & TUTORIALS (released: Apr-14) To extract a shell mesh from a solid mesh, first select some faces. Extracted surface mesh PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 74 PAM-RTM 2014 © 2014 ESI Group Mesh > Create > Node Creates a new node with the specified (x, y, z) coordinates. Create node dialog box Mesh > Cleanup > Merge Coincident Nodes It can sometimes happen that elements in a mesh are not connected, i.e. they have geometrically common nodes, but these nodes are actually different entities (they are nodes with different IDs but with the same coordinates). This problem can be fixed by PAM-RTM. The user enters a merge tolerance, i.e. the smallest allowable distance between 2 nodes. If 2 elements are closer than the specified distance, they will be considered the same node, and the elements connectivity will be modified accordingly. Mesh > Cleanup > Reverse Normals (selection) This command updates the nodes connectivity of the selected elements so that their normal vector points in the opposite direction. Mesh > Cleanup > Align Normals (auto) Automatically aligns the normal vectors based on the picked element. The picked element is used as the starting element in an algorithm that visits all the elements of the mesh from neighbor to neighbor, and changes nodes connectivity if needed to have the normal vector of an element pointing in the same direction as its neighbors. Mesh > Cleanup > Delete Unreferenced Nodes It is possible that some nodes in a mesh are not referenced by any element. This command is used to delete all the unreferenced nodes of the current mesh. PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 75 USER’S GUIDE & TUTORIALS (released: Apr-14) Mesh > Cleanup > Delete Selected Entities Deletes the selected nodes or elements. If nodes are deleted, the elements referring to these nodes will, of course, be deleted. Each time an entity is deleted, groups of nodes and groups of faces are also updated to make sure they don’t refer to deleted entities. Mesh > Cleanup > Delete Degenerate Elements Deletes degenerate elements in a mesh, which are defined as elements referring more than once to the same node. Mesh > Cleanup > Swap Diagonal Modifies the connectivity table of 2 adjacent elements, so that their diagonal (common edge) is swapped. Mesh > Check This command tries to find problems in a mesh. First it looks for degenerated elements, i.e. elements that have the same node ID appearing twice or more in their connectivity table. Then it outputs some information about the smallest and largest elements in the mesh, which can be useful for “debugging” a simulation. Finally it lists all the elements with a volume 1000 times smaller than the largest volume. This can also help to find problems, especially with volume meshes in which it can occur that very small elements are generated in the center of the part. Output of the Mesh->Check command PAM-RTM USER'S GUIDE Mesh Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 76 PAM-RTM 2014 © 2014 ESI Group Mesh > Info This command outputs some general information about a mesh, for example the number of elements of each type, the number of nodes, the group IDs, and some geometrical information like bounding box (min and max coordinates of a box containing all the nodes), span (size of the part in the x, y, z directions), and the volume of the mesh. Output of the Mesh->Info command Mesh > Info Pick This command opens the following dialog box, which lets the user pick nodes or elements and get info on the picked entities. Info Pick dialog box PAM-RTM USER'S GUIDE Mesh Menu PAM-RTM 2014 © 2014 ESI Group 77 USER’S GUIDE & TUTORIALS (released: Apr-14) VIEW MENU View > Curve Viewer Opens the curve viewer dialog box. See section Curve Viewer. View > Orientations > K1 Only Used to visualize vectors in the K1 direction (see next figure). Note · It is very important to understand the difference between the permeability directions and the fiber directions of a reinforcement. Most of the time, when you import a ply with File->Import->Laminate, the K1 and K2 directions are fiber directions, not permeability directions. The fiber directions are transformed to permeability directions with the Mesh->Orientations->Compute Local Permeability command. The same menu is used to visualize orientation vectors. Depending on the context, these vectors will be interpreted by the user as fiber directions or permeability directions. Visualization of the K1 direction (actually the f1 direction or warp direction) View > Orientations > K2 Only Displays the K2 direction only. PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 78 PAM-RTM 2014 © 2014 ESI Group View > Orientations > K1 and K2 Displays the K1 and K2 directions together. View > Orientations > None Clears the display of orientations. View > Outline > Part Plots the outline and the sharp edges of the mesh displayed in the current window (it can be the injection mesh or a ply mesh). The display of sharp edges is based on the Outline Critical Angle parameter available in the View->Options->Display dialog box. By default, this value is 40 degrees, which means that an edge common to two neighbor elements will be plotted if the angle between the two elements is greater than 40 degrees. A lower value would result in more line segments plotted. View > Outline > Free Edges This command plots free edges in a mesh of shell elements, i.e. edges that are not shared by more than one element. This is useful to find connectivity problems in a mesh. View > Outline > Plies It is possible to have the outline of all the draped plies (imported through File->Import>Draping Results) plotted in the same window as the injection mesh, as shown in the next figure. This can be useful to analyze problems with Map Draping Results. PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 79 USER’S GUIDE & TUTORIALS (released: Apr-14) Visualization of plies outline with the injection mesh View > Flow Front The flow front position can be visualized on top of any scalar field. The user must import first the flow front file generated by the PAM-RTM™ solver (extension .front), with File->Import->Scalar Field->PAM-RTM Flow Front. Flow front position (white line) on top of a temperature result PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 80 PAM-RTM 2014 © 2014 ESI Group View > Normal Vectors This command can be used to visualize normal vectors on shell elements or the external skin of a solid mesh. View > Zones Visibility Opens the following dialog box, which is used to activate or deactivate the visualization of some zones. This can be useful to visualize results on internal zones completely surrounded by solid elements. This situation happens for example when the cavity and the mold are meshed with solid elements. Zones visibility dialog box View > Cutting Plane Opens the Cutting Plane dialog box, used to specify the parameters of a cutting plane. When Clipping is checked, visualization of graphics entities is disabled on one side of the plane. When Cross Section is checked, the intersection of the plane with a solid mesh is calculated and displayed. The plane is defined in space by entering the coordinates of a point and the normal vector of the plane. Coordinates can be specified exactly by the user. Otherwise, a node of the mesh can be picked with the mouse to define the plane’s position. When the position is defined, another node can be picked to define the normal vector. PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 81 USER’S GUIDE & TUTORIALS (released: Apr-14) Cutting plane dialog box Picking of nodes to define the cutting plane PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 82 PAM-RTM 2014 © 2014 ESI Group Display of the filling factor with the cutting plane active View > Post-Processing This command opens the Post-Processing dialog box, used to set post-processing parameters. The first group of parameters is related to animation. Animation can be activated or stopped with the On/Off check box. When Proportional is checked, each animation frame is displayed for a time that depends on the simulated time and the Loop Time. The loop time specifies the total time to display all the frames. It is specified in seconds. For example, if a filling simulation generates output for times 1 s., 2 s., 5 s., 10 s., and if the loop time is set to 10 (s), the first frame would be displayed for 1 s., the second one for 3 s., the third one for 5 s. and the last frame is always displayed for some fixed time on which the user doesn’t have control (2 s.). If proportional is not checked, each frame is displayed the same time. With the same example, since there are 4 frames to display in 10 seconds, each frame would be displayed for about 2.5 s. Note that there is nothing that warns the user if the computer is not able to achieve this frame rate. The second set of post-processing parameters is related to the color scale. There are many options to control the range of the color scale : - Auto Step: PAM-RTM™ automatically adjusts the color scale based on the min and max values of each time step of the visualized scalar field. PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 83 USER’S GUIDE & TUTORIALS (released: Apr-14) - Auto All: the min and max values of all the time steps are used as the range of the color scale. - Fixed: the values specified by the user in the Min and Max fields are used. - Min Fixed: only the value specified in the Min field is fixed, the max value is automatically adjusted for each step. - Max Fixed: only the value specified in the Max field is fixed, the min value is automatically adjusted for each step. The number of color levels in the color scale is set with Nb Levels. Post-processing parameters The third set of parameters concerns the visibility of faces. If On/Off is checked, it means that some faces will be hidden. There are 4 options to control the visibility threshold: PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 84 PAM-RTM 2014 © 2014 ESI Group - Under: only faces with a scalar field value lower than the value specified in the Min field are displayed. - Between: only faces with a scalar field value between the values specified in the Min and Max field will be displayed. - Not Between: only faces with a scalar field value lower than the value specified in the Min field or greater than the value in the Max field will be displayed. - Above: only faces with a scalar field value greater than the value specified in the Max field will be displayed. Finally, the Show velocity vectors check box allows velocity vectors to be displayed on top of the currently visualized contour. For instance, it is possible to display velocity vectors on top of a temperature contour. The Scale value can be used to apply a scale factor to the velocity vectors, in case they are displayed too short or too long by default. The colored arrows option allows vectors to be colored based on their norm. The proportional length option, when active, displays arrows of size proportional to the norm of the vectors. Since velocity vectors close to the flow front are typically very small compared to vectors close to inlets, uncheck this option to visualize them correctly. These two last options are only available for post-processing of parallel solver results. View > Symmetry This command is useful when a simulation was run on mesh representing only half a part for symmetry reasons. It is possible using this command to recreate the complete mesh, to produce pictures for a report, for example. The symmetry plane can be chosen as X-Y, Y-Z or X-Z. The position of the symmetry plane must also be specified by entering the 3 coordinates of a point in the Position text fields. View->Symmetry dialog box View > Delete N Last Steps It sometimes happens that the last states of a filling calculation are not significant. For instance, depending on the outlet conditions, it could happen that only a few elements are filled in the last steps in a very long time. This command is used most of the time in PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 85 USER’S GUIDE & TUTORIALS (released: Apr-14) the context of the display of an animation, or for the generation of an AVI file. It allows exclusion of the n last steps from the animation. Of course this command doesn’t delete anything in results files. It just prevents the last steps from being displayed. View > Set Same Viewpoint When many graphics windows are opened, it can be useful to set the same viewpoint (rotation) for all the views. This command sets the same viewpoint for all views of all open documents, based on the active view. Activate first the window that you want to use as the reference. Result of the Set Same Viewpoint command. The active window is the left one. View > Options > Paths This tab is used to set the path to the PAM-RTM™ standard solver executable (pamrtm.exe) and the parallel solver (pamrtm_dmp.exe). The PAM-QUIKFORM solver (quik_form.exe), MPI version used to run the parallel solver, and other executables are also specified in this tab. Normally these paths don’t need to be changed. They are set by the InstallShield when PAM-RTM™ is installed. However in some special situations like a minor PAM-RTM™ update that doesn’t ship with an InstallShield, the path could be changed manually by the user. See section Material Database for information about the path to the material database. PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 86 PAM-RTM 2014 © 2014 ESI Group Paths tab PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 87 USER’S GUIDE & TUTORIALS (released: Apr-14) View > Options > Display Display tab There are many viewing parameters that can be set through the Display tab. - when it is checked, this parameter tells PAMRTM™ to turn on display optimizations relevant for closed geometry (usually Closed geometry optimizations: PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 88 PAM-RTM 2014 © 2014 ESI Group solids), such as culling (elimination at the first stage of the graphics pipeline of back facing polygons). If the user suspects rendering problems, for example faces that are not displayed, this optimization should be turned off. - If Closed geometry optimizations is active, so is culling, which means that the normal vector has an effect on the faces that will be displayed. By default, PAMRTM™ manages to have normal vector of the front facing polygons point in the direction of the viewer. However if the user notices some strange “inverse effects”, for example when rotating the mesh it seems to turn in the inverse direction, the Reverse inside/outside parameter should be checked. - The Polygon Offset flag is used to offset the element faces by some small distance so that the element edges can be displayed with better quality. Some graphics cards might not support this OpenGL feature very well, so it can be turned off if you suspect a problem. - Draw points as marks: by default, nodes are displayed with OpenGL points. Problems with OpenGL points have been seen on some graphics cards. If the Draw points as marks check box is checked, nodes will be displayed as a small x instead of points. - Specular Lighting: this flag is used to turn on or off specular lighting, i.e. the lighting that makes surfaces appear shiny. By default specular lighting is on. - By default, only nodes on the external skin of solid meshes are displayed in PAMRTM™. Internal nodes can be checked to visualize nodes inside solid meshes. This can be useful to create sensors by picking internal nodes. - The Point Size parameter controls the half size of points, in pixels. - Vectors Scale Factor: - Outline Critical Angle: - Picking Size: - Orientations on skin: by default, PAM-RTM™ calculates the length of vectors such that they have a reasonable size when projected in the graphics window. If the vectors appear too small or too large on screen, the user can apply a scale factor to the vectors. For example, if 0.5 is specified, the vectors will be 2 times smaller. this parameter controls drawing of sharp edges. PAMRTM™ determines sharp edges based on the angle between 2 adjacent faces. If too many sharp edges (false edges) are drawn, you should increase the value of this parameter. The maximum value is 90 degrees. this parameter can be used to modify the picking sensibility. It specifies the diameter of a circle (in pixels) around the point where the mouse button is clicked. The default value is 6 pixels. This means that to pick a node, for example, the user can click at most 3 pixels away from the node. If you think it’s too difficult to pick nodes with the default settings, you should increase the value of this parameter. this option concerns solid meshes only. If the option is not checked, orientation vectors are displayed for all elements of the mesh, including internal elements. Orientation vectors are displayed with an arrow starting at the center of gravity of the element. If the option is checked, orientation vectors will only be displayed for elements on the skin of the solid (external boundary), thus PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 89 USER’S GUIDE & TUTORIALS (released: Apr-14) reducing the number of vectors displayed. Also, the center of gravity of the external face will be used as the origin for the display of orientation vectors, instead of the center of gravity of the element, which should lead to better visualization in general. - Select hidden entities: by default, selection using a rectangular box only selects visible entities (nodes, faces, elements). It is sometimes useful, for instance when working on a solid model, to select entities located inside the solid. When this option is activated, all the entities that project inside the rectangle defined by the user will be selected, whether they are visible or not. View > Options > Colors The user can change the color of many graphics entities with the Options->Color tab. For example the default background color (white by default) can be changed by pushing the arrow on the Background button. This pops up a color chooser with a selection of pre-defined colors (see next figure). If the user doesn’t find the color he wants in the pre-defined colors, he can use the More Colors button to popup the standard Windows Color Chooser. The default color of faces, nodes, etc., can also be changed. When the user changes one of these colors, the modified color settings are saved in the Windows registry. It is possible to come back to the original PAM-RTM™ default values with the Factory Defaults button. Colors tab PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 90 PAM-RTM 2014 © 2014 ESI Group Standard Windows color chooser The Zones and Groups button allows the user to customize the color scale used to display zones and groups. 20 colors are available for this color scale. If there are more than 20 groups or zones to display, the colors are re-used. Note that it is still possible to use the color scale that was used in version 2004 for groups and zones with View->Color Scale->RGB. Default color palette used to display groups and zones View > Color Scale Enables the user to select the color space used to interpolate colors in the color scale. RGB, HSV and GREY color spaces are available. PAM-RTM USER'S GUIDE View Menu PAM-RTM 2014 © 2014 ESI Group 91 USER’S GUIDE & TUTORIALS (released: Apr-14) View > Color Schemes The user can select with this menu between a Black Background or White Background color scheme. For example, when the black background is selected, the color used for text is automatically set to white. View > Lights The View->Lights menu is used to turn on or off one of the 6 predefined lights. View > Refresh Forces the redraw of the active window. Use CTRL-R as a shortcut. PAM-RTM USER'S GUIDE View Menu USER’S GUIDE & TUTORIALS (released: Apr-14) 92 PAM-RTM 2014 © 2014 ESI Group PROCESS PARAMETERS The process parameters will be presented in the following sections for each simulation type. Many parameters are common to many simulation types, so instead of repeating text we refer to the section where the parameter was first described. RTM Simulation Filling Tab RTM process parameters - Injected resin: drop-down list allowing the user to select the resin to be injected. This list contains the names of all the resins currently defined in the model. - Max injection time: - Use gravity: - Gravity Norm: - Dir. X, Dir. Y, Dir. Z: the simulation will stop even if the part is not completely filled if the maximum injection time is reached. tells PAM-RTM™ to take gravity into account when calculating the resin pressure field. gravitational acceleration. Unit: m/s2. components of the gravity direction vector. By default gravity is in the negative Z direction. PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 93 USER’S GUIDE & TUTORIALS (released: Apr-14) Velo Opti Tab The reference for the velocity optimization (voids minimization) functionality of PAMRTM™ is: Ruiz E, Achim V, Soukane S, Trochu F, Bréard J. Optimization of injection flow rate to minimize micro/macro-voids formation in resin transfer molded composites. Composites Science and Technology 66 (2006) 475–486. tells PAM-RTM™ to adjust the injection flow rate so that the voids percentage is minimal in the final part. Pressure controlled inlets are converted to flow rate controlled. If this parameter is not checked and the micro and macro voids functions are defined, PAM-RTM™ won’t optimize the velocity but will calculate the micro and macro void values. This is useful to have an idea of the void content that you would have at the end of the injection if you didn’t control the flow rate. - Optimize velocity: - Resin capillary coef: the capillary number is defined as: Ca * = µv γ cos θ where µ is the fluid viscosity, v the superficial velocity, γ the surface tension, and θ the contact angle between the resin and the fibers. The resin capillary coef is the term γ cos θ . PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 94 - Optimal capillary number: - Micro voids function: the function - Macro voids function: - Nb max iter: - Tolerance: of the capillary number. PAM-RTM 2014 © 2014 ESI Group the capillary number minimizing the void content. describing the micro voids content, as un function the function describing the macro voids content, as un function of the capillary number. the maximum number of Darcy’s equation resolutions done each time step of filling to optimize the flow front velocity. the convergence error allowed in the optimization process. Please see the tutorial Velocity Optimization for more information. VARI Simulation Filling Tab See RTM Simulation. VARI Tab VARI Process tab PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 95 - External pressure: - Continue overfilling: - Overfilling time: - Nb steps: USER’S GUIDE & TUTORIALS (released: Apr-14) most of the time the default atmospheric pressure (100 000 Pa) is used, but if the infusion is done in an autoclave, a higher pressure could be specified. when checked, simulation will continue even if the part is filled. That allows the user to study the relaxation of the reinforcement after filling, and estimate how long it takes to reach thickness equilibrium. Different scenarios are possible. For instance the inlet could be kept on after filling is complete, or closed with the Trigger Manager. the duration of the post-filling phase. the number of steps to compute for the post-filling phase. A constant time step is used, given by overfilling_time/nb_steps. Heated RTM Simulation Filling Tab See RTM Simulation. Thermal Tab Heated RTM process parameters - Initial fibers temperature: initial temperature applied on the fibers just before the resin starts entering the cavity. This value is not used if Use temperature file is checked. Unit: degree Kelvin. PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 96 - Initial mold temperature: initial temperature of the mold. Use temperature file is checked. Unit: degree Kelvin. - Initial degree of cure: - Use temperature file: PAM-RTM 2014 © 2014 ESI Group This value is not used if degree of cure of the resin just before entering the cavity. check this parameter if you want to initialize temperature in the mold and fibers with a non-uniform temperature field, result of a preheating simulation. Use the … button to browse to the file containing initial temperature. That file is x_Thermal_p.dof with the standard solver, xt.unf with the parallel solver, where x is the name of the preheating case. Note: · It is also possible to specify initial temperature per zone. However zone temperature will be ignored if use temperature file is active. Chaining Tab PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 97 USER’S GUIDE & TUTORIALS (released: Apr-14) tells PAM-RTM™ to perform overfilling, i.e. let the resin flow out of the vents for some time after the part is completely filled. This is useful to get a more uniform degree of cure distribution before starting the actual curing. The overfilling stage is optional. You could chain curing directly after filling, without overfilling. - Continue overfilling: - Overfilling time: - Nb steps: - Continue curing: check this parameter if you want PAM-RTM™ to continue with a curing simulation after filling or overfilling. - Stop criterion: if max_curing_time is selected, the curing simulation will run until curing_time is reached. The min_above option will stop the simulation when all elements have at least the degree of cure specified in degree of cure target, while the avg_above option will stop the simulation when the average degree of cure on the mesh is above degree of cure target. - Curing time: - Degree of cure target: the degree of cure to avg_above options are selected. - Time step: Unit: seconds. the time allowed for the resin to flow out of the vents after filling. the number of steps of overfilling, i.e. the number of Darcy’s resolutions after the part is filled. selected. seconds. the time allowed for curing when the max_curing_time option is reach, when the min_above or the time step for the curing simulation is explicitly set by the user. Unit: Preheating Simulation Preheating process parameters - Initial fibers temperature: - Initial mold temperature: initial temperature of the fibers. Unit: degree Kelvin. initial temperature of the mold. Unit: degree Kelvin. PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 98 PAM-RTM 2014 © 2014 ESI Group Note: · It is also possible to specify initial temperature per zone. Presimulation No process parameters are available for presimulation. Curing Simulation Curing process parameters - Resin: if many resins are defined in your document, you have to choose which resin to use for the curing simulation from this drop-down list. - Initial fibers temperature: - Initial mold temperature: initial temperature in zones linked to mold material. This parameter is not used if Use temperature file is checked. Unit: degree Kelvin. - Initial degree of cure: initial temperature in zones linked to fiber reinforcements. This parameter is not used if Use temperature file is checked. Unit: degree Kelvin. initial degree of cure assigned to all the elements in the cavity. This parameter is not used if Use degree of cure file is checked. By default, the curing simulation assumes that the cavity is completely filled (filling factor is 1 everywhere in the cavity). The only way to take into account partially filled elements is with the degree of cure file. PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 99 - Use temperature file: - Use degree of cure file: USER’S GUIDE & TUTORIALS (released: Apr-14) check this option and browse to the x_Thermal_f.dof to initialize temperature with a non-uniform field resulting from the Heated RTM simulation. With the parallel solver the file to select is xt.unf. check this option and browse to the x_Curing_f.dof to initialize the degree of cure with a non-uniform field resulting from the Heated RTM simulation. With the parallel solver the file to select is xcr.unf. Note: · It is also possible to specify initial temperature per zone. However zone temperature will be ignored if use temperature file is active. Compression RTM Simulation Filling Tab See RTM Simulation. Compression Tab CRTM process parameters PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 100 - Initial mold opening: - Compression direction: PAM-RTM 2014 © 2014 ESI Group this is the thickness difference from start to end of compression (h1 in the figure below). In case of a vertical mold displacement (compression direction –Z), the initial mold opening corresponds to the displacement of the tool. the vector in the global coordinate system defining the compression direction. If a zero length vector is specified, the normal vector of each element is used as the compression direction. Note: · The initial mold opening doesn’t correspond to an empty gap. PAM-RTM™ modeling of CRTM assumes that the preform always fills completely the cavity. · The final thickness of the part is specified on zones. Even though in general the same final thickness will be specified on all the zones, it is possible to specify a different final thickness on each zone if needed. The initial thickness is automatically computed by PAM-RTM™ so that at the end of compression the thickness matches the thickness of zones. This means the initial thickness could change from element to element, depending on the element’s normal and the compression direction. The initial thickness is hf+h2, where h2 is the projection of h1 on the local normal vector. compression direction n h1 h2 h1 (initial mold opening) hf (final thickness) hf hf hf hf PAM-QUIKFORM Simulation There are basically two process parameters for a PAM-QUIKFORM simulation: axis (also called draping referential) and operation. Even though axis do not appear in the PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 101 USER’S GUIDE & TUTORIALS (released: Apr-14) process folder of the explorer, they are clearly process parameters since they are used to specify contact point and draping direction. Another process parameter, used only in advanced applications, is the draping curve. It is possible to import a draping curve with the Import Curves command available in the popup menu associated to the Process item in the explorer. See description of the curve parameter in the PAM-QUIKFORM solver manual. It is possible to create many axis in a PAM-QUIKFORM document. An axis is used as a referential on which a laminate is aligned before it is draped. The origin of the referential can be seen as the contact point, and the local X axis of the referential is the draping direction for a zero degree layer. A draping operation is the association of a laminate, an axis and optionally a geometrical support (a selection of elements of the tool mesh). If the geometrical support is not specified, it is assumed that a layer is to be draped on the complete tool mesh. A laminate part is defined by specifying a sequence of draping operations. For example: - Drape laminate 1 from axis 1. - Drape laminate 2 on axis 2. - etc. Axis Definition To create an axis, right-click the axis item in the explorer and choose Create. To edit an axis, double-click it in the explorer, or choose Edit in the axis popup menu. This opens the Axis Definition dialog. PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 102 PAM-RTM 2014 © 2014 ESI Group The coordinates of the origin can be entered manually, or an arbitrary point can be picked on the tool mesh with the Pick button [1]. The direction vector (local X axis of the referential) can also be entered manually, or interactively by picking points. First choose 1 Point or 2 Points option [2]. If 1 Point is chosen, push the Pick button [3] and pick one point. The direction vector is then defined from the origin to the picked point. If 2 Points is used, push the Pick button [3], then pick two points on the tool mesh. The direction vector is then defined from the first picked point to the second. Draping Sequence Before the sequence of draping operations can be specified, some axis and laminates must be defined (see chapter Laminates). To create a new operation, use the New Operation command in the Process popup menu. To edit an operation, double-click it in the explorer, or choose Edit in the popup menu. New operations are always added at the end of the operation sequence. It is not possible to move an operation in the sequence once it is created. Editing an operation pops up the following dialog box, where the laminate to drape and the associated axis can be selected from the list of available entities. PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 103 USER’S GUIDE & TUTORIALS (released: Apr-14) Optionally, it is possible to set a geometrical support to an operation. The use of supports will be demonstrated with the following example. A rectangular surface is to be draped first with a layer of fabric. Then a layer of UD is draped on top of the fabric. The UD layer doesn’t cover the surface completely. The mesh used in this example is the following. First we set the draping referential to the center of the part. When using supports, it is important that the referential used in a draping operation be located on the support. Then we create 2 laminates: one for the fabric layer, and one for the UD layer. The next step is to create 2 operations. The first one is associated to the fabric layer, the second one to the UD layer. PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 104 PAM-RTM 2014 © 2014 ESI Group Finally we set the support of the UD operation. Set the selection filter to Element then select elements like this. Use the Set Support From Selection command, available in the operation popup menu, to set the support of operation 2. To visualize later the support of an operation, use the Set Selection from Support command. To modify a support, first use Set Selection from Support to clear the current selection and set it to the elements of the support, then modify selection (use these buttons to replace, add to, or remove from selection), and finally set the support with Set Selection from Support. At this point the explorer looks like this. PAM-RTM USER'S GUIDE Process Parameters PAM-RTM 2014 © 2014 ESI Group 105 USER’S GUIDE & TUTORIALS (released: Apr-14) Running the simulation, we get the following results. The fabric layer covers the surface completely, while the UD layer is restricted to elements of the support. PAM-RTM USER'S GUIDE Process Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) PAM-RTM USER'S GUIDE Process Parameters 106 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 107 USER’S GUIDE & TUTORIALS (released: Apr-14) NUMERICAL PARAMETERS The numerical parameters will be presented in the following sections for each simulation type. Many parameters are common to many simulation types, so instead of repeating text we refer to the section where the parameter was first described. RTM Simulation Output Tab RTM Output tab - Save Filling Factor: - Save Pressure: - Save Velocity: tells PAM-RTM™ to generate result file for filling factor. save pressure result file. save resin velocity results files. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 108 PAM-RTM 2014 © 2014 ESI Group - saves the capillary number, micro void, macro void, total void files. This option is useless if the micro and macro voids functions in the Velo Opti tab of the Process Parameters are not defined. - Save closing force: - Save viscosity: - I-DEAS Universal is the default format used by PAM-RTM™ to write simulation results. The new ESI Group format called ERF is also available to perform post-processing in Visual-Viewer™ (version 5.5 or later). VisualViewer™ has more advanced post-processing capabilities than the standard PAMRTM™ viewer. - Sampling period: - Save capillary numbers: writes a 5 columns text file, giving the components of the force vector in time, as well as norm of the force vector. save resin viscosity. This is useful in the isothermal RTM context for viscosity function of time. Output format: store results in output files each n time step. By default n=10, which means that 1/10 steps will be saved. This parameter is useful to minimize the size of results files. Other options (parallel solver only): - seconds: - fill %: saves results approximately each x seconds of simulated time saves results approximately each y percentage of filling Recover period: (standard solver only) this parameter is useful in case you need to stop the simulation (CTRL-C) and restart it later. The default value is 500, which means that if you need to stop the simulation, you will have 500 steps to recalculate if you do a restart. Since a restart is considered an exceptional event, the default value is relatively large so that the simulation doesn’t waste time writing unnecessary files. If you expect a simulation to run many days, you should maybe consider decreasing the recover sampling period. Notes: - The “save” options (save filling, save pressure, etc.) only apply to the standard solver. The parallel solver writes systematically all the results files, regardless of that selection. - One exception is the “save micro/macro voids” option that must be selected in order to have the parallel solver compute the micro and macro voids. - The seconds and fill percentage sampling period options might not be respected, depending on the time step. For example, with a sampling period of 4 seconds and a time step of 5 seconds, results would be saved at t=0, t=5, t=10, instead of t=0, t=4, t=8, etc. From the time of the last save, the specified period is added, and the first step computed with a time greater or equal to that time generates a save. Of course with a small time step, the actual sampling period will be closer to the specified value. - The parallel solver can be restarted from any time. It will actually restart from the closest time in the results files (depends on the sampling period). PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 109 USER’S GUIDE & TUTORIALS (released: Apr-14) One Shot Tab RTM One Shot tab - (standard solver only) tells PAM-RTM™ to perform a “one shot” simulation, i.e. solve in a single step to get the last points filled. This simulation is orders of magnitude faster than a standard filling simulation. Only pressure and flow rate boundary conditions are taken into account. There can be many inlets specified, but all must be of the same type (pressure or flow rare). Vents are ignored, as the goal of this simulation is to help find the best location for vents. Do one shot: PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 110 PAM-RTM 2014 © 2014 ESI Group Air Entrapment Tab RTM Air Entrapment tab tells PAM-RTM™ to detect air traps and take into account the pressure inside the air trap when solving the resin pressure field. An air trap is defined as a closed region of empty or partially filled elements not connected to an open vent. - Detect air traps: - Min. number of elements: this parameter is used to avoid false air traps to be detected. The default value is 3, which means that if a small air trap of one or two elements pops up from nowhere, it won’t be considered a real air trap and the cavity pressure still applies in this area (no pressure calculation based on the volume of the air trap). This doesn’t mean that an air trap can never be smaller than 3 elements. Actually a large air trap is allowed to shrink below the min number of elements parameter. PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 111 USER’S GUIDE & TUTORIALS (released: Apr-14) GenPorts tab if this box is checked, the GenPorts optimization module will be called to find the optimal injection ports locations minimizing fill time, instead of the standard RTM filling calculation. - Optimize inlets locations: - Nb inlets: - Nb generations: - Population: - Prob mutation: - Steady gen: number of injection ports to use. engine. number of generations to be calculated by the genetic algorithm the number of individuals for each generation. An individual is actually an injection configuration, which is made of the number of injection points specified in nb inlets. this is the probability that a major change occurs in a child with respect to his parents. For instance if a child is normally generated on the “line” connecting his 2 parents, a mutation could be to choose randomly a node of the mesh instead of one of the parents. if the calculation engine doesn’t detect a significant change in the solution for that number of successive generations, it will assume convergence has been reached and will stop the calculation. More information can be found in the GenPorts tutorial. Note that GenPorts is not supported by the parallel solver. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 112 PAM-RTM 2014 © 2014 ESI Group Local Variables Tab RTM Local Variables tab - Use local permeability files: tells the PAM-RTM™ solver to initialize local permeability (one permeability value for each element) from the x_k1.sf, x_k2.sf and optionally x_k3.sf (for solid elements) that have been generated as a result of Compute Local Permeability. For example if you do Compute Local Permeability and save your PAM-RTM™ project as test.dtf, the files test_k1.sf and test_k2.sf will be generated in the same directory. You have to check Use local permeability files to initialize local permeability from these files. Otherwise the permeability of the material associated to each zone will be used. - Use local porosity file: - Use local thickness file: tells PAM-RTM™ to use the local porosity file (x_porosity.sf) resulting from Compute Local Permeability to initialize the porosity of each element. PAM-RTM USER'S GUIDE Numerical Parameters the same principle applies to the thickness of shell elements. PAM-RTM 2014 © 2014 ESI Group 113 USER’S GUIDE & TUTORIALS (released: Apr-14) Advanced Numerical Parameters RTM Numerical Parameters - Advanced tab Advanced Darcy solver parameters PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 114 - Use parallel solver: - Correct flow rate with tube length (Poiseuille): - Use AMG solver: - Overfill factor: - Darcy solver parameters PAM-RTM 2014 © 2014 ESI Group if this box is checked, the new high performance parallel solver introduced in PAM-RTM™ 2010 will be called instead of the standard solver. Before the calculation is launched, a dialog box is posted, asking how many processors are to be used. It is possible to enter 1 if the calculation is to be run on a single processor system, such as a laptop. In that case, the calculation will still be much faster than the standard solver, as the parallel solver uses a completely different code architecture, highly optimized. The memory used will also be much smaller than the standard solver. Once the calculation is done, the results have to be loaded for post-processing with File > Open > PAM-RTM Parallel (.unf). Note that not all the functionalities of the standard solver are currently supported by the parallel solver. Please see the PAM-RTM™ Release Notes for the complete list of features supported or not supported. (parallel solver only) for pressure driven inlets, the corresponding flow rate on each inlet is computed and compared to the theoretical flow rate that would be obtained using Poiseuille formula (i.e. taking into account the tube length and radius specified on the boundary condition). If the flow rate on the inlet is found to be greater than that value, the inlet is switched to a flow rate controlled inlet with the flow rate set as the Poiseuille value. (parallel solver only) new high performance multi-grid solver used to solve Darcy’s equation. Experimental (use with care). (standard solver only) used to speed up the filling calculation by allowing more elements to be filled at each iteration, thus reducing the total number of Darcy solutions needed to fill the cavity (in PAM-RTM™ most of the time is spent solving Darcy’s equation). The idea is to allow an element to be oversaturated, i.e. to contain more resin than it can actually contain. The excess of resin of an element is distributed to its neighbors. The default value is 1.2, meaning that an element can be oversaturated by 20%. · (standard solver only): the method used to solve the linear system Ax=b. Conjugate gradient should be used for Darcy. Advanced users can evaluate the performance of other supported methods: Bi-conjugate gradient Bi-conjugate gradient stabilized Conjugate gradient squared Chebyshev iteration Generalized Minimum Residual (GMRES) Richardson iteration Quasi-minimal residual Conjugate gradient 2002 Conjugate gradient 2004 Conjugate gradient 2008 Iterative method: PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 115 USER’S GUIDE & TUTORIALS (released: Apr-14) Notes: · A new conjugate gradient implementation (conjugate gradient 2008) is introduced in PAM- RTM™ 2008. The meaning of the conjugate gradient option without version specification depends on the platform. For instance, on Windows 32-bit, conjugate gradient actually means conjugate gradient 2004. On Windows 64-bit, conjugate gradient means conjugate gradient 2008. The 2008 implementation was introduced mainly for porting reasons. Unfortunately the 2004 implementation, which is still the fastest of all implementations, makes use of advanced libraries which are not available on Windows 64-bit and Linux. We recommend keeping the default generic conjugate gradient option, so that the PAM-RTM solver automatically chooses the best implementation for a platform. · Preconditioner: · Nb max iter: · Error: diagonal should be used for Darcy. Other choices for advanced users are: Incomplete Cholesky Incomplete LU maximum number of iterations to solve the linear system. The residual is defined as ri = b − A ∗ xi . The stopping criterion of the iterative method is ri b 2 ≤ ε , where ε is the specified error. 2 VARI Simulation (standard solver only) The VARI simulation shares many of its numerical parameters with the RTM simulation. In the following sections, we list only the VARI specific parameters. The user should refer to the section RTM Simulation for a description of other parameters. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 116 PAM-RTM 2014 © 2014 ESI Group VARI output parameters Output Tab Since VARI simulation involves local change of thickness, fiber content (porosity) and permeability, these variables can be saved in results files. See RTM Simulation for other parameters. Air Entrapment Tab See RTM simulation. PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 117 USER’S GUIDE & TUTORIALS (released: Apr-14) Advanced Tab VARI advanced numerical parameters - Overfill factor: see RTM simulation. - Unified Darcy solver parameters: these are specific settings to solve the unified Darcy equation. The default settings are GMRES with ILU preconditioner. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 118 PAM-RTM 2014 © 2014 ESI Group Heated RTM Simulation Output Tab Heated RTM output tab - Save filling factor, Save pressure, Save temperature, Save extent of cure, Save exothermy, Save velocity, Save micro/macro voids, Save viscosity: (standard solver only) check boxes to specify the variables to save in results files. - Save closing force: writes a 5 columns text file, giving the components of the force vector in time, as well as norm of the force vector. - Output format: - Sampling period: - Recover period: PAM-RTM USER'S GUIDE Numerical Parameters see RTM simulation. see RTM simulation. see RTM simulation. PAM-RTM 2014 © 2014 ESI Group 119 USER’S GUIDE & TUTORIALS (released: Apr-14) Note: - The exothermy output of the standard solver is replaced by the rate of reaction (dα/dt) in the parallel solver. Air Entrapment Tab The air entrapment option can be used with non-isothermal filling, however the current implementation doesn’t take into account the effect of temperature on the pressure inside air traps. See RTM Simulation for a description of the parameters. Local Variables Tab See RTM simulation. Advanced Tab Heated RTM advanced parameters PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 120 PAM-RTM 2014 © 2014 ESI Group - Use parallel solver: see RTM simulation. Thermal analysis with the parallel solver was introduced in PAM-RTM™ 2011. - Use kinetic: - Correct flow rate with tube length (Poiseuille): - (standard solver only) check this parameter to have PAMRTM™ take into account thermal dispersion, which is basically a correction to the thermal conductivity used in the saturated region. The corrected conductivity depends on the resin velocity. For more details, see the description of the characteristic length parameter, in the section on the thermal properties of the fiber reinforcements. - Overfill factor: - Parallel Solver Specific Params: uncheck this parameter when resin cure and its effects on viscosity and temperature are negligible during the filling phase, to avoid solving the transport equation for chemical species and reduce CPU time. see RTM simulation. Use thermal dispersion: see RTM simulation. is checked. these parameters are only used if use parallel solver - Automatically generate mold/preform interface: with the parallel solver, it is mandatory to specify a heat transfer coefficient for the mold/preform interface, as opposed to the standard solver for which it is optional. Since it can be a lot of work to generate that interface manually with the usual Groups>Contact Interface command, this option is checked by default, meaning the elements will be automatically disconnected on that interface for the whole mesh at calculation launch. In some special situations the user might need to specify different coefficients for different areas of the mold/preform interface. In that case, the user has to create interfaces manually; using contact resistances (see tutorial Thermal Contact Resistance). Be careful that the units of the contact resistance are the reciprocal of the mold/preform interface coefficient. This option must be unchecked if some contact resistances are to be defined manually on the mold/preform interface. In that case it is mandatory that all the faces of the mold/preform interface be part of a contact resistance. PAM-RTM™ won’t create automatically the remaining interfaces if the contact resistances cover only a subset of the mold/preform interface. Note that this doesn’t apply to mold/mold interfaces. It is thus possible to have automatically generate mold/preform interface checked, while contact resistances for mold/mold interfaces are defined - Mold/preform interface coefficient: heat transfer coefficient (conductance) used on the whole mold/preform interface when the automatically generate 2 mold/preform interface option is checked. Be careful that the units (W/m K) are the reciprocal of a thermal resistance. - Use AMG solver: (parallel solver only) new high performance multi-grid solver used to solve Darcy’s equation. Experimental (use with care). PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 121 - Darcy Solver Params: - Thermal Solver Params: USER’S GUIDE & TUTORIALS (released: Apr-14) see RTM simulation. These parameters are only used by the standard solver (i.e. if use parallel solver is unchecked). default is GMRES with ILU preconditioner. These parameters are only used by the standard solver (i.e. if use parallel solver is unchecked). Preheating Simulation Output Tab Preheating output tab - Save temperature: - Output format: - Sampling period: - Recover period: simulation. this is the only variable that can be saved for a preheating see RTM simulation. see RTM simulation. see RTM simulation. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 122 PAM-RTM 2014 © 2014 ESI Group Time Step Tab Preheating time step tab With the standard solver, the preheating simulation works with a constant time step calculated as: dt = Max experiment time/Max number of steps - Max experiment time: the total heating time of the mold and fibers. Unit: seconds. - Max number of steps: the number of time steps for the calculation. The parallel solver uses an adaptive time step, meaning it changes in time to respect convergence criteria. The dt formula above corresponds to the maximum time step. Advanced Tab See Heated RTM. PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 123 USER’S GUIDE & TUTORIALS (released: Apr-14) Curing Simulation Output Tab Curing output tab - Variables available for saving in results files are: temperature, extent of cure and exothermy. - Output format: - Sampling period: - Recover period: see RTM simulation. see RTM simulation. see RTM simulation. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 124 PAM-RTM 2014 © 2014 ESI Group Time Step Tab Curing time step tab - Max experiment time: see Preheating simulation. - Max number of steps: see Preheating simulation. - Adaptive max delta T: (parallel only) in order to capture the high temperature peak typical of curing reactions, it is sometimes necessary to use this parameter to further control the time step. It specifies the maximum absolute temperature variation allowed on the whole domain between two steps. If the variation is higher, the time step will be decreased (divided by two), until the condition is respected. Then the time step will increase again as long as the condition is respected (up to the maximum time step dt = max_experiment_time/max_number_of_steps). The default value is zero, meaning the parameter has no effect. Advanced Tab See Heated RTM simulation. PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 125 USER’S GUIDE & TUTORIALS (released: Apr-14) Presimulation (standard solver only) Presimulation numerical parameters - Save filling factor: there is no pressure calculation involved in presimulation, so filling factor is the only variable available for output. - Sampling period: - Overfill factor: see RTM simulation. see advanced numerical parameters of RTM simulation. PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 126 PAM-RTM 2014 © 2014 ESI Group PAM-QUIKFORM Simulation - Grid size u: size of the elements along the local Y axis of the draping referential (see figure below). For fabrics, grid size v is not used. Only grid size u is used for both directions. The UD algorithm supports different sizes for u and v. - Grid size v: - Project: - Extrapolate: - Back drape: - Flat curve: size of the elements along the local X axis of the draping referential. This value is not used for fabrics. if this option is checked, the fiber orientations are projected by PAMQUIKFORM on the tool mesh, and instead of writing mesh files of the 3D draped plies, the tool mesh is copied for each ply, with additional information for fiber orientations. See description of the initial parameter in the PAM-QUIKFORM solver documentation. also called “manual draping”, this option is used by PAM-QUIKFORM to cover a surface as much as possible by extrapolation. Without this option, draping will cover at most a quadrangle defined by the size of the two axes first draped. See example below. activates the possibility of draping in back direction. The basic algorithm of PAM-QUIKFORM drapes from the starting point, increasing weft and warp directions. Due to the geometry of some parts, the basic algorithm might not be able to cover some areas without the back drape option. See example below. if this option is active, PAM-QUIKFORM projects the boundary of the tool on the mesh of the 3D draped ply in order to get a more accurate representation of the 2D flat pattern. PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group 127 if the flat curve option is active, the flat curve is written in IGES - IGES Curve: - Sequential: if this - PHP, MEM, CSV: format. USER’S GUIDE & TUTORIALS (released: Apr-14) option is active, PAM-QUIKFORM will drape sequentially by zones, which must be numbered sequentially from 1 to n. The origin of the draping referential must be located in zone 1. documentation. special application flags. See PAM-QUIKFORM solver PAM-QUIKFORM grid size u and v parameters PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 128 Draping without the extrapolate option Draping with the extrapolate option PAM-RTM USER'S GUIDE Numerical Parameters PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 129 USER’S GUIDE & TUTORIALS (released: Apr-14) Draping without the “back drape” option Draping with the “back drape” option Flat curve PAM-RTM USER'S GUIDE Numerical Parameters USER’S GUIDE & TUTORIALS (released: Apr-14) 130 PAM-RTM 2014 © 2014 ESI Group FUNCTION EDITOR Many simulation parameters in PAM-RTM™ use curves or mathematical functions of 2 variables. This chapter describes the function editor, a dialog box used to edit these mathematical functions. Overview This button is used in PAM-RTM™ wherever a mathematical function can be assigned to a simulation parameter. The following image shows the General tab of the Fabric Properties dialog. In this example, Permeability K3 [1] is a constant value, so its value can be entered directly in the text field. Permeability K1 [2] has an exponential curve assigned to it. The text field is used to display the type of the function, the text field is disabled, and the user has to push the button to modify the parameters of the exponential curve. This opens the Function Editor dialog. General tab of the Fabric Properties PAM-RTM USER'S GUIDE Function Editor PAM-RTM 2014 © 2014 ESI Group 131 USER’S GUIDE & TUTORIALS (released: Apr-14) Function editor dialog In this example, an exponential curve f ( x ) = A ⋅ e B⋅x with A=2.2E-8 and B=-11.57 is assigned to Permeability K1. The user can select other functions from the list of predefined functions [1]. Selecting a function displays either the function parameters such as A and B in this example, or the coordinates of the control points if the function is defined by a set of control points (piecewise_linear or krig_e). In any case, the user can click on a value and enter text to modify it. A user_defined function is always available in the list of functions. The same exponential curve as shown above could be defined with the user_defined function by pushing the Edit User Defined button and entering the character string: 2.2E-8*exp(-11.57*x) The curve is the same, however the evaluation of the curve costs more CPU time. PAM-RTM USER'S GUIDE Function Editor USER’S GUIDE & TUTORIALS (released: Apr-14) 132 PAM-RTM 2014 © 2014 ESI Group The curve can be visualized by pushing the View button. This opens the following Curve Plotter. Permeability K1 as a function of fiber content User Defined Functions The parser recognizes the following operators: +, -, *, /, ^ (exponent) as well as the following functions: H, abs, exp, ceil, floor, log, sqrt, sin, cos, tan, asin, acos, atan, sinh, cosh, tanh. Note that the non-standard function H is the Heavyside step function, defined as: H ( x ) = 0, x < 0 H ( x ) = 1, x ≥ 1 As an example, the function Kinetic_01 defined as: f ( x, y ) = A ⋅ y ⋅ (1 − y ) ⋅ e m PAM-RTM USER'S GUIDE Function Editor p −E x PAM-RTM 2014 © 2014 ESI Group 133 USER’S GUIDE & TUTORIALS (released: Apr-14) with A=9.17E+6, E=7304, m=0.7 and p=1.3 would be defined as a user_defined function with the character string: 9.17E6*(y^0.7)*((1-y)^1.3)*exp(-7304/x) Function Pool The function pool can be seen as some kind of copy/paste functionality for mathematical functions. This is useful when the same function is assigned to many parameters. In that case, the user defines the function once, then push the Copy to Function Pool button, which pops up the following dialog box. A name must be given to the function before it is copied in the function pool. The function can be retrieved later by its name with Get from Function Pool. Note that the function pool is shared by all open documents and is available until PAM-RTM™ is closed. Copy to function pool dialog Get from function pool dialog PAM-RTM USER'S GUIDE Function Editor USER’S GUIDE & TUTORIALS (released: Apr-14) 134 PAM-RTM 2014 © 2014 ESI Group Import/Export Depending on the context (edition of a function of 1 or 2 variables), it is possible to import in PAM-RTM™ a 2 columns text file (curve) or a 3 columns text file (function of 2 variables). The columns can be separated with any combination of white space, tab or comma. If a 2 columns file is imported, a piecewise_linear curve is automatically created. For 3 columns text files, a krig_e function is created. The set of control points associated to piecewise linear or kriged functions can also be exported in 2 or 3 columns text files. PAM-RTM USER'S GUIDE Function Editor PAM-RTM 2014 © 2014 ESI Group 135 USER’S GUIDE & TUTORIALS (released: Apr-14) MATERIAL PROPERTIES OF THE RESIN The Resin Properties dialog box is opened by double-clicking a resin in the model explorer. The following dialog box is used to specify resin properties such as viscosity, chemical reaction model, thermal conductivity and specific heat. General Tab PAM-RTM USER'S GUIDE Material Properties of the Resin USER’S GUIDE & TUTORIALS (released: Apr-14) 136 PAM-RTM 2014 © 2014 ESI Group Name Enter a text description to fully identify the resin. It is sometimes useful to include in this description the validity domain of the associated viscosity and kinetics models, such as “My resin with kinetics 350 < T < 400”. Density Density of the resin. Unit: kg/m3. Viscosity Unit: Pa.s. Several models are available: - Constant - Function of temperature f(temperature) - · Constant · Exponential: · Piecewise linear function · User defined · User DLL f ( x ) = A ⋅ exp( B ⋅ x ) Function of temperature and degree of cure f(temperature, alpha) · Constant · Viscosity_01 (see reference [R.1] at the end of this chapter): B f (T , α ) = A ⋅ exp + C ⋅ α T · Viscosity_02 (Castro-Macosko [R.2]): c c f (T , α ) = c0 ⋅ exp 1 ⋅ 2 T c2 − α · Viscosity_03: f (T , α ) = c1 ⋅ exp( · c3 + c4 ⋅α c c2 ) ⋅ exp 3 − c5 T c4 − α Viscosity_04: c c f (T , α ) = c0 ⋅ exp 1 ⋅ 2 T − c1 c2 − α · c3 T − c ⋅α 4 Viscosity_05: f (T , α ) = A ⋅ exp( PAM-RTM USER'S GUIDE Material Properties of the Resin B + c0 + c1α + c2α 2 + ... + c6α 6 ) T PAM-RTM 2014 © 2014 ESI Group · 137 USER’S GUIDE & TUTORIALS (released: Apr-14) Viscosity_06 ([R.3]): T f (T , α ) = hu ⋅ exp rheo + C ⋅ α T − Tm - - · Kriged function · User defined · User DLL Function of time f(global_time) · Constant · Piecewise linear function · User defined · User DLL Function of time f(material_age) · Constant · Piecewise linear function · User defined · User DLL Note: · The user_dll type is only supported by the parallel solver. See tutorial User defined functions. · The time variable used for the evaluation of viscosity f(global_time) is the time since beginning of injection. At a given time, the viscosity is uniform on the saturated domain. · For f(material_age), the time variable corresponds to the time since a resin particle entered the mold. Viscosity is thus non-uniform on the saturated domain, and higher close to the resin front. · The f(material_age) model is only supported by the parallel solver. · The viscosity model is selected with the Model dropdown list[1]. In case of a constant viscosity, the value can be entered directly in the Value field. Otherwise the user has to go through the function editor [2] to enter the coefficients of the selected function (see section Function Editor). PAM-RTM USER'S GUIDE Material Properties of the Resin USER’S GUIDE & TUTORIALS (released: Apr-14) 138 PAM-RTM 2014 © 2014 ESI Group Thermal Tab Thermal Conductivity Unit: W/m.K. Available models are: constant, function of temperature, or function of temperature and degree of cure [1]. Once again, in case of a constant model, the value can be entered directly in the text field [2]. Otherwise use the … button to open the function editor. Specific Heat Unit: J/Kg.K. Available models are: constant, function of temperature, or function of temperature and degree of cure [3]. Note · When using the parallel solver, if specific heat f(temperature, alpha) is needed, it has to be specified with a user_dll function (i.e. C-language code written by the user). See tutorial User Defined Functions. PAM-RTM USER'S GUIDE Material Properties of the Resin PAM-RTM 2014 © 2014 ESI Group 139 USER’S GUIDE & TUTORIALS (released: Apr-14) Chemical Tab Enthalpy Unit: J/Kg. The heat generated by the full resin polymerization per unit mass. Reaction model The resin kinetics model is defined as a weighted summation of sub-reactions: n dα = ∑ wi (t ) ⋅ f i (T , α ) dt i =1 The number of sub-reactions n must be specified first in the Nb sub-reactions field. Then the user pushes the Set button [1], which actually generates the sub-reactions listed in [2]. Select a sub-reaction, then edit the associated weight function and kinetics function [3]. The weight is function of time, while the kinetics function is function of temperature and degree of cure. Available functions for kinetics are: - Kinetic_01 (autocatalytic [R.4]): −E p f (T , α ) = A ⋅ α m ⋅ (1 − α ) ⋅ exp T PAM-RTM USER'S GUIDE Material Properties of the Resin USER’S GUIDE & TUTORIALS (released: Apr-14) - 140 PAM-RTM 2014 © 2014 ESI Group Kinetic_02 (Kamal-Sourour [R.5]): E E n f (T , α ) = A1 ⋅ exp 1 + A2 ⋅ exp 2 ⋅ α m ⋅ (B − α ) T T - Kinetic_03 (modified Kamal-Sourour): E E n (T ) f (T , α ) = A1 ⋅ exp 1 + A2 ⋅ exp 2 ⋅ α m (T ) ⋅ (B (T ) − α ) T T B (T ) = b0 + b1 ⋅ T + b2 ⋅ T 2 m(T ) = m0 + m1 ⋅ T + m2 ⋅ T 2 n (T ) = n0 + n1 ⋅ T + n2 ⋅ T 2 - Kinetic_04 [R.3]: − Tkin ⋅ [ramp (1 − exp(− B ⋅ (T − Tm )) − α )]m ⋅ α n f (T , α ) = A ⋅ exp α − Tm ramp( x ) = x, x ≥ 0 ramp( x ) = 0, x < 0 - Kriged function: interpolation function constructed from a set of data points. - User defined - User DLL (parallel solver only, see tutorial User defined functions) The View button [4] opens the Kinetic Viewer Parameters dialog, used to specify a temperature and time range. Then pushing the Plot button plots isothermal conversion dα curves, as shown below. This is actually the time integration of for different dt temperatures. This viewer is useful to quickly evaluate how long it takes to fully cure the resin at a given temperature. PAM-RTM USER'S GUIDE Material Properties of the Resin PAM-RTM 2014 © 2014 ESI Group 141 USER’S GUIDE & TUTORIALS (released: Apr-14) Kinetic Viewer References [R.1] A.M. Stolin, A.G. Merzhanov, A.Y. Malkin, Polymer Engineering and Science; 1979, 19, 1074 [R.2] J.M. Castro, C.W. Macosko, Studies of mold filling and curing in the reaction injection molding process, AIChE J., 1982, 28, 250 [R.3] M. Henne, C. Breyer, M. Niedermeier, P. Ermanni, A new kinetic and viscosity model for liquid composite molding simulations in an industrial environment, Polymer Composites, 2004, 25, 3 [R.4] A.M. Clayton, Epoxy Resins, Engineered Material Handbook: Composites, ASM International, 1998 [R.5] M.R. Kamal, S. Sourour, Kinetics and thermal characterisation of thermoset cure, Polymer Engineering and Science, January 1973, Vol. 13, No. 1 PAM-RTM USER'S GUIDE Material Properties of the Resin USER’S GUIDE & TUTORIALS (released: Apr-14) 142 PAM-RTM 2014 © 2014 ESI Group MATERIAL PROPERTIES OF THE FIBER REINFORCEMENTS Three types of fiber reinforcements can be created in PAM-RTM™: fabric, unidirectional, and random mat. Right-click the Reinforcements item in the explorer to create new instances of reinforcements. To edit a fiber reinforcement, double-click it in the model explorer. The General, Thermal and Compressibility tabs are shared by all reinforcements. An Advanced tab is available on the fabric to specify permeability as a function of shear angle. A Draping tab is available in the context of a PAM-QUIKFORM simulation. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements PAM-RTM 2014 © 2014 ESI Group 143 USER’S GUIDE & TUTORIALS (released: Apr-14) General Tab Name Enter a text description to fully identify the fiber reinforcement. Density Unit: kg/m3 Density of the “solid” fiber material, i.e. density for 100% fiber volume fraction. For example density of pure glass, if the reinforcement is made of glass fibers. Permeability K1, K2, K3 Unit: m2 Permeability in the 3 principal directions of the permeability tensor, i.e. the directions in which the tensor is diagonal. K1, K2 and K3 are the values on the principal diagonal. The in-plane principal permeability components K1, K2 and through-thickness permeability K3 are most of the time specified as constant values for a given fiber volume fraction (vf). They can also be specified as functions of vf. It is important for VARI simulation to specify permeability as a function of vf. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements USER’S GUIDE & TUTORIALS (released: Apr-14) 144 PAM-RTM 2014 © 2014 ESI Group The models available for permeability as a function of vf, which can be selected through the function editor [1], are: - Exponential: f ( x ) = A ⋅ exp( B ⋅ x ) - Power: f ( x) = A ⋅ x B - Piecewise linear - Kriged (interpolation of experimental data points) - User defined Compressibility Tab The parameters in this tab are currently only used for VARI simulation. Compressibility format The format of the compressibility curve, which can be specified as one of the following: - Pressure as a function of fiber content (vf), PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements PAM-RTM 2014 © 2014 ESI Group - 145 USER’S GUIDE & TUTORIALS (released: Apr-14) Stress as a function of strain. Strain is defined between -1 and 0. Zero strain corresponds to natural thickness. Compressibility curve Here is the list of functions that can be selected in the function editor, opened by pushing the Compressibility Curve button [1]: f ( x) = A ⋅ x B - Power: - Piecewise linear - Kriged (interpolation of experimental data points) - User defined Here is an example of a compressibility curve specified as Pressure-Vf . A power law is used with A = 1.7E+11 and B = 7.6. Natural thickness Unit: m This is the thickness of the reinforcement at ambient pressure. Superficial density Unit: Kg/m2 The superficial density of a single layer of reinforcement or a ply. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements USER’S GUIDE & TUTORIALS (released: Apr-14) 146 PAM-RTM 2014 © 2014 ESI Group Thermal Tab Thermal conductivity K1, K2, K3 Unit: W/m.K This is the thermal conductivity of the “solid” fiber material, as if the reinforcement had a fiber volume fraction of 100%. For example for a glass fiber reinforcement, the thermal conductivity of pure glass would be specified. It is only used in the dry area. In the wet area the effective conductivity is used (see below). It can be specified as orthotropic, in which case principal directions need to be set. Use the Direction dropdown list [1] to set the current direction (K1, K2 or K3), then choose the Model [2] which can be constant or f(temperature). If f(temperature) is specified, use the function editor [3] to define the conductivity curves. A different curve can be assigned to K1, K2 and K3. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements PAM-RTM 2014 © 2014 ESI Group 147 USER’S GUIDE & TUTORIALS (released: Apr-14) Note · The principal directions of the permeability and conductivity tensor are assumed to be the same. It is not possible in the current version of PAM-RTM™ to specify different directions for permeability and conductivity. · When using the old solver, the thermal conductivity values have to be multiplied by porosity. Effective conductivity K1, K2, K3 Unit: W/m.K This is the conductivity of the mixture of resin and fibers that PAM-RTM™ uses in the saturated region. In general the user could use the rule of mixture (keff = vf.kf + (1-vf).kr) to calculate the effective conductivity, but in some cases a modified value could be used to take into account thermal dispersion for instance. The effective conductivity can be specified orthotropic. It can be modeled as constant, f(temperature) or f(temperature, alpha). Note · When using the parallel solver, if effective conductivity f(temperature, alpha) is needed, it has to be specified with a user_dll function (i.e. C-language code written by the user). See tutorial User Defined Functions. Specific heat Unit: J/Kg.K The specific heat of the “solid” fiber material, i.e. 100% fiber volume fraction. Characteristic length Unit: m The characteristic length is referred to as the characteristic scale of the elliptical shape of a compressed fiber tow in which case it is given by l = a b . This parameter is used in the context of thermal dispersion modeling. It doesn’t have any effect in the calculation if use thermal dispersion in the advanced numerical parameters is not checked. Please see the introduction chapter of this user’s manual for details on thermal dispersion modeling. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements USER’S GUIDE & TUTORIALS (released: Apr-14) 148 PAM-RTM 2014 © 2014 ESI Group Advanced Tab (Fabrics) The parameters in this tab are currently only used in the context of a local permeability calculation taking into account fiber directions of a draped fabric. See Mesh->Compute Local Permeability. Sheared permeability K1, K2, K3 Unit: m2 Allows the specification of permeability as a function of the shearing angle and initial fiber content. Sheared rotation angle Unit: angle (degree) Allows the specification of the rotation angle of the K1 principal permeability direction relative to the weft as a function of the shearing angle and initial fiber content. The following pictures explain the rotation of the principal permeability directions when a fabric is sheared by an angle α relative to the weft. The principal direction K1 is rotated by an angle β relative to the warp. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements PAM-RTM 2014 © 2014 ESI Group 149 USER’S GUIDE & TUTORIALS (released: Apr-14) Draping Tab The parameters in this tab are currently only used in the context of a PAM-QUIKFORM simulation. Fabric Locking angle Unit: degree. This is the maximum shearing of the fabric before wrinkles occur. PAM-QUIKFORM will stop calculation in areas where the locking angle is reached. Default value is 90 degrees. Validity range is between zero and 90 degrees. Unidirectional Grid stretch Unit: no unit, percentage. In areas of high curvature, the PAM-QUIKFORM UD algorithm can increase the distance between fibers (parameter grid size u in the PAM-QUIKFORM numerical parameters), up to the grid stretch percentage, in order to respect the grid shear criteria below. Default value: 200 %. Grid shear Unit: degree. Maximum allowable shear angle of the unidirectional. PAM-RTM USER'S GUIDE Material Properties of the Fiber Reinforcements USER’S GUIDE & TUTORIALS (released: Apr-14) 150 PAM-RTM 2014 © 2014 ESI Group MATERIAL PROPERTIES OF SOLIDS The material called solid in PAM-RTM™ should be used to specify any nonpermeable material such as foam or metallic inserts. The Solid Properties dialog box is opened by double-clicking a “solid” in the model explorer. General Tab Name Enter a text description to fully identify the material. PAM-RTM USER'S GUIDE Material Properties of Solids PAM-RTM 2014 © 2014 ESI Group 151 USER’S GUIDE & TUTORIALS (released: Apr-14) Density Unit: kg/m3 Density of the material. Thermal Tab Thermal Conductivity Unit: W/m.K Can be specified as constant or function of temperature. Specific Heat Unit: J/Kg.K Constant or function of temperature. PAM-RTM USER'S GUIDE Material Properties of Solids USER’S GUIDE & TUTORIALS (released: Apr-14) 152 PAM-RTM 2014 © 2014 ESI Group LAMINATES Laminate materials are made of layers of fiber reinforcements or solids. Currently laminates are used in PAM-RTM™ in the context of a PAM--QUIKFORM™ simulation, and also in the context of local permeability calculation, to link reinforcements to imported draped plies. A new laminate is created by right-clicking the Laminates item in the explorer, and choosing the New command. Right-clicking a laminate’s top level item gives access to the popup menu common to all materials. The Edit command pops up a dialog box, which currently only allows modification of the material name. PAM-RTM USER'S GUIDE Laminates PAM-RTM 2014 © 2014 ESI Group 153 USER’S GUIDE & TUTORIALS (released: Apr-14) It is possible to insert, copy, delete layers by right-clicking one layer in the explorer. Editing a layer opens the following dialog box, used to associate a reinforcement or solid to this layer. Material Choose the material to link to this layer from the roll-down list. All currently defined reinforcements and solids are listed. Angle Unit: degree Angle of the layer in the laminate referential (α in the figure below). Thickness PAM-RTM USER'S GUIDE Laminates USER’S GUIDE & TUTORIALS (released: Apr-14) 154 PAM-RTM 2014 © 2014 ESI Group Unit: meters Thickness of the layer. Porosity Unit: no unit, percentage expressed as a value between zero and one. Initial porosity of the layer (before shearing in case of fabrics). Shear Angle Unit: degree Initial shearing of the layer (fabrics only, β in the figure below). In the following figure a layer’s referential (Lx-Ly) was rotated by an angle α relative to the laminate’s referential (X-Y). The layer’s x axis defines the warp direction of a fabric, and the layer’s y axis is the weft direction. A non-zero initial shear angle β was specified. Y Ly weft Lx β warp α X PAM-RTM USER'S GUIDE Laminates PAM-RTM 2014 © 2014 ESI Group 155 USER’S GUIDE & TUTORIALS (released: Apr-14) MATERIAL DATABASE The user can create his own material database with the materials he/she uses most often. Creation of the Material Database This is the procedure to create the material database the first time PAM-RTM™ is run. The path to the material database has to be specified in the Paths tab of the Options dialog box (View->Options). Before the path is explicitly set by the user, it is blank in the Options dialog. To set the path, the user pushes the browse button (see [1] in image below) which opens the standard Windows file browser. Then the user is asked to select an existing .dtf file. Since the first time the software is used that .dtf file doesn’t exist, the user has to create first an empty .dtf file with a text editor. That file could be named for example materials.dtf. Note that the material database is actually a subset of the PAMRTM™ input file, so it has the same extension .dtf. The path to the material database is a current user setting, which means that all PAMRTM™ users working on the same computer have to set it. If many users need to share the same material database, the materials.dtf file could be placed in a directory where all users have read and write permissions. PAM-RTM USER'S GUIDE Material Database USER’S GUIDE & TUTORIALS (released: Apr-14) 156 PAM-RTM 2014 © 2014 ESI Group 1 Paths tab of the Options dialog box Using the Material Database Once the initial empty materials.dtf file has been created and the path set, you can start building the database. First completely define your material with the Reinforcement, Resin or Solid editors of PAM-RTM™. Once you are satisfied with the PAM-RTM USER'S GUIDE Material Database PAM-RTM 2014 © 2014 ESI Group 157 USER’S GUIDE & TUTORIALS (released: Apr-14) material definition, right-click the material in the explorer and choose Add to User Database. Later if you want to reuse the same material in another simulation, you can retrieve materials from the database by right-clicking the Materials item in the explorer and choosing Get from User Database. This opens the following dialog box, which lists all the materials available in the database. Choose one or more materials you want to copy in your current model. If there is a material with the same name in the current document, PAM-RTM™ asks for a confirmation that you want to replace it with the version stored in the material database. It is important to understand that when retrieving a laminate from the material database, PAM-RTM™ retrieves also all the materials used in the definition of the laminate. PAM-RTM USER'S GUIDE Material Database USER’S GUIDE & TUTORIALS (released: Apr-14) 158 PAM-RTM 2014 © 2014 ESI Group Get from User Database dialog If you need to make some changes to one of the materials of the database, you have to retrieve it first from the database into the current model. Then edit the material and send it back to the database with Add to User Database. If you didn’t modify the material name, PAM-RTM™ detects that a material with the same name already exists in the database and asks if you want to replace it. Answer Yes. The command Simulation->Manage User Database opens the following dialog box, which is actually almost the same as the previous one, except that there is a Delete button that allows the user to remove the unwanted materials from the database. This is the only database management functionality currently available. PAM-RTM USER'S GUIDE Material Database PAM-RTM 2014 © 2014 ESI Group 159 USER’S GUIDE & TUTORIALS (released: Apr-14) Manage User Database dialog PAM-RTM USER'S GUIDE Material Database USER’S GUIDE & TUTORIALS (released: Apr-14) 160 PAM-RTM 2014 © 2014 ESI Group BOUNDARY CONDITIONS Boundary conditions in PAM-RTM™ are associated to groups of nodes or groups of faces as their geometrical support. So the first step is to create a group to define where a boundary condition is applied, then create the actual boundary condition which refers to the group through its ID. To create a boundary condition, right-click the Boundary Conditions item in the model explorer. The types of boundary conditions that can be created depend on the simulation type. The newly created boundary condition is not assigned to any group. Double-click the new boundary condition in the explorer to set its parameters. This opens the Boundary Condition dialog box. PAM-RTM USER'S GUIDE Boundary Conditions PAM-RTM 2014 © 2014 ESI Group 161 USER’S GUIDE & TUTORIALS (released: Apr-14) The first parameter to specify is the group ID to which this boundary condition refers. If there are many groups, it can be difficult to identify a group with the color bars, so simply push the Pick Node button and pick a node that belongs to the group. The Parameters area contains the list of parameters associated to this boundary condition. For instance, all the boundary conditions have a State parameter which allows to activate or deactivate the boundary conditions as a function of time. To use the state parameter, simply create a piecewise linear curve. When the value is >= 0.5 the boundary condition is active, otherwise it is disabled. Actually all the parameters of boundary conditions are functions of time. For example, the Flow Rate boundary condition contains three parameters: flow_rate, resin_temperature and state. All three parameters can be functions of time. Use the button to open the function editor [1]. The only exception is the convection coefficient, which is by default a function of time, but can be made a function of temperature if the convection coef f(temperature) option is checked at the bottom of the dialog box. This check box is only available when a convection boundary condition is edited. PAM-RTM USER'S GUIDE Boundary Conditions USER’S GUIDE & TUTORIALS (released: Apr-14) 162 PAM-RTM 2014 © 2014 ESI Group Here’s a list of all boundary conditions with the simulation types that support them. - - - - Pressure · Description: pressure controlled inlet. · Simulations: RTM, VARI, Heated RTM. · Parameters: Pressure. Inlet pressure. Unit: Pa. Resin_Temperature. Resin temperature when it enters the cavity. This parameter is used most of the time for Heated RTM simulations, but it makes sense to use it also for isothermal simulations, for example to have PAM-RTM™ calculate the viscosity from a viscosity curve. Unit: degree Kelvin. State Tube length. The length of the tube between the pressurized resin pot and the mold. Only used when the Poiseuille correction is activated in the advanced numerical parameters. Unit: m. Tube radius. Also only used with the Poiseuille correction. Unit: m. Flow Rate · Description: flow rate controlled inlet. · Simulations: RTM, VARI, Heated RTM, Presimulation. · Parameters: Flow_Rate. Unit: m3/s . Resin_Temperature. Unit: Kelvin State Max Pressure. The flow rate inlet supports a special parameter to specify the maximum pressure that can be reached by the injection machine. This parameter is not a function of time. Vent · Description: resin outlet. · Simulations: RTM, VARI, Heated RTM, Presimulation. · Parameters: Pressure. The pressure on the vent. Unit: Pa. State. Useful to “program” a vent opening and closing sequence. Temperature · Description: fixed temperature, i.e. Dirichlet boundary condition in the heat transfer equation. · Simulations: Heated RTM, Preheating, Curing. · Parameters: PAM-RTM USER'S GUIDE Boundary Conditions PAM-RTM 2014 © 2014 ESI Group 163 - - · Description: imposed heat flux, i.e. Neumann boundary condition in the heat transfer equation. · Simulations: Heated RTM, Preheating, Curing. · Parameters: Heat_Flux. State. ∂T = q . Unit: W/m2. ∂n Convection ∂T = h(T∞ − T ) ∂n · Description: · Simulations: Heated RTM, Preheating, Curing. · Convection coef f(temperature): check to make the convection coefficient a function of temperature instead of time. · Parameters: Reference_Temperature. T∞ in the equation above. Unit: Kelvin. Convection_Coefficient. h coefficient. Unit : W/m2.K State. Contact Resistance · Description: used to model the heat transfer on the interface between two solids in contact. · Simulations: Heated RTM, Preheating, Curing. · Parameters: - Temperature. Unit: Kelvin. State. Heat Flux - USER’S GUIDE & TUTORIALS (released: Apr-14) T1 − T2 , where T1 and T2 Rth are the temperatures on both sides of the interface. Unit: m2W-1K State. Contact_Resistance. Rth in equation ϕ = Thickness · Description: prescribed thickness on the part boundary. · Simulations: VARI. · Parameters: Thickness. Unit: m. State. PAM-RTM USER'S GUIDE Boundary Conditions USER’S GUIDE & TUTORIALS (released: Apr-14) - 164 PAM-RTM 2014 © 2014 ESI Group Compression · Description: used in the context of Compression RTM simulation, to specify the upper mold closing velocity and the compression direction. · Simulations: Compression RTM. · Parameters: Velocity_Norm. The upper mold closing velocity. Unit: m/s. Final_Thickness. The targeted final thickness of the part. This is only used as a hint for the Compression RTM simulation to determine the time step, it is not a stopping criteria. Unit: m. Dir_x, Dir_y, Dir_z. The components of the direction vector for compression. If the direction to be used is normal to each element, the three components must be set to zero. Unit: none. State. Notes: only applies to flow rate inlets. - Max pressure - Tube length - Convection coef f(temperature) PAM-RTM USER'S GUIDE Boundary Conditions and tube radius only apply to pressure inlets. only applies to convection boundary conditions. PAM-RTM 2014 © 2014 ESI Group 165 USER’S GUIDE & TUTORIALS (released: Apr-14) NON-COINCIDENT INTERFACES Non-coincident interfaces allow disconnected meshes to be used for thermal calculations. Typically they allow different meshing parameters to be used for the preform area and the mold. For instance the preform could be meshed with tetrahedral, while the mold is meshed with bricks. Also the size of the elements can be different on both sides of the interface. An example is shown below. A folder non-coincident interfaces is available for thermal calculations (preheating, heated RTM, curing). To create a non-coincident interface, right-click on the non-coincident interfaces item, then New, which opens the non-coincident interface dialog box. PAM-RTM USER'S GUIDE Non-Coincident Interfaces USER’S GUIDE & TUTORIALS (released: Apr-14) 166 PAM-RTM 2014 © 2014 ESI Group The main parameters to specify are the two zone IDs involved in the interface. In general the master zone is the preform, and the slave zone is the mold. The master zone and slave zone dropdown lists allow selection of one of the zones currently defined in the model. It is recommended to assign meaningful names to zones before defining interfaces, to make that selection easier. The heat transfer coefficient is a parameter specific to each interface, meaning it is possible to have in the same model many interfaces with different heat transfer coefficients. The in-plane tolerance corresponds to the maximum distance around an element of the master surface where a node of the slave surface can be found. The perimeter tolerance corresponds to the maximum distance between the two surfaces in order to have a contact (distance normal to the plane of the interface). In general, a good tolerance value should be about half the size of the elements on the preform side, and it is recommended to use the same value for in-plane and perimeter tolerances. However if the mesh has a quite heterogeneous mesh size, these tolerances may be too small (and thus, there will be "no contact", and thus no heat transfer at these non-coincident interfaces). If such a case occurs, one can change (i.e. increase) these tolerances. One should however be careful not to use too large tolerances so that nodes beyond the opposite surface would be taken into account. PAM-RTM USER'S GUIDE Non-Coincident Interfaces PAM-RTM 2014 © 2014 ESI Group 167 USER’S GUIDE & TUTORIALS (released: Apr-14) SENSORS Creating Sensors Sensors are used in PAM-RTM™ to sample results on specific points in order to plot curves. To create sensors, open the Create Sensors dialog box, either by right-clicking the Sensors item in the explorer, or by using the Simulation->Create Sensors command, which pops up the following dialog box. First give a name to the sensor, so you can identify it easily. However try to give a short name because this name will be used in the graph legend when results are plotted. There are two methods to create sensors: one point and two points. With the one point method, the user either enters the coordinates of the sensor directly, or pushes the Pick button to pick with the mouse an arbitrary point on the mesh. Then the user pushes the Create button to actually create the sensor. PAM-RTM USER'S GUIDE Sensors USER’S GUIDE & TUTORIALS (released: Apr-14) 168 PAM-RTM 2014 © 2014 ESI Group With the two points method, the user specifies two points that define the end-points of a line segment. The idea is to have PAM-RTM™ generate automatically a specified number of sensors on that line. The two end-points can be specified by entering the coordinates or by picking with the mouse. The line segment doesn’t have to lie on the surface. In case of curved geometry, PAM-RTM™ projects the sensors on the surface. A Preview button is available to visualize the approximate position of the sensors, before they are projected. When the two points method is used, the name of the sensor is used as a root name, and a number is automatically added to this name. For example, if the user specifies the name as s and 3 sensors are created, they will be called s_1, s_2, s_3. The names can be modified later. As shown below, the created sensors are listed in the explorer under the Sensors item. Selecting a sensor in the explorer highlights it in the graphics window. This behavior is controlled by the Highlight Selected command available in the popup menu on the Sensors item. It is also possible with the View All command to turn on or off the visualization of all sensors in the graphics window. PAM-RTM USER'S GUIDE Sensors PAM-RTM 2014 © 2014 ESI Group 169 USER’S GUIDE & TUTORIALS (released: Apr-14) Editing Sensors Once they have been created, it is possible to modify attributes of a sensor by doubleclicking it in the explorer, or by using the menu that pops up when a sensor is rightclicked in the explorer. The edit command opens the Sensor Properties dialog box. With this dialog box the user can change the name of the sensor and its coordinates. A sensor can be deleted by selecting it in the explorer and by choosing Delete in its popup menu. Plotting sensors There are two ways to plot curves on sensors. The simplest one is by using the Plot command available in the sensor popup menu. This command samples the currently visualized scalar field on the sensor position, then opens the curve viewer and adds a new curve to it. So to use this command, activate first visualization of a scalar field such as pressure or temperature. Another way is to open first the curve viewer with View->Curve Viewer. Then use the Import Curves command of the curve viewer popup menu, available by right-clicking in the curve viewer graphics window, as shown below. Select one of the sensor results files generated by the solver (for example x_Temperature_Filling_Sensors.dat). This loads all the curves available in the file in the curve viewer. PAM-RTM USER'S GUIDE Sensors USER’S GUIDE & TUTORIALS (released: Apr-14) 170 PAM-RTM 2014 © 2014 ESI Group While the first approach is more convenient because you don’t have to import a file in the curve viewer, the second approach is more accurate. This is because with the first approach, the number of values plotted depend on the sampling period parameter, while in sensor results files all the time steps are saved. PAM-RTM USER'S GUIDE Sensors PAM-RTM 2014 © 2014 ESI Group 171 USER’S GUIDE & TUTORIALS (released: Apr-14) TRIGGER MANAGER The trigger manager is a module allowing easier control of opening and closing of injection ports and vents. The user defines triggers and outcomes. A trigger specifies a condition such as “filling factor on sensor x equals 1”, actually meaning “the resin has reached sensor x”. Associated to a trigger is a list of outcomes, i.e. events that are generated when the condition is met. For instance, an outcome could be “set the state coefficient of injection port y to 1”, actually meaning “open injection port y”. This allows easy definition of sequential injection used for large parts, in which injection ports are successively opened and closed. Running such simulations with earlier versions of PAM-RTM™ was possible, but required more work as the user had to run many simulations to estimate the time of arrival of the resin on a given point. With the trigger manager a single run is required. Note that many outcomes can be associated to a trigger, such as “closing vent x” and “opening injection port y”. Also conditions on the volume of resin injected or lost are available on triggers, i.e. the user could define conditions such as “when a volume x of resin has been lost on vent y, close vent y and open injection port z”. PAM-RTM USER'S GUIDE Trigger Manager USER’S GUIDE & TUTORIALS (released: Apr-14) 172 PAM-RTM 2014 © 2014 ESI Group A folder Triggers is available in the document’s tree. Right-clicking the Triggers folder gives access to the New command to create triggers. To create outcomes, the user rightclicks a trigger and selects New Outcome. Double-clicking a trigger or an outcome in the document’s tree opens a dialog box for edition of the entity. These dialog boxes are described below. PAM-RTM USER'S GUIDE Trigger Manager PAM-RTM 2014 © 2014 ESI Group 173 - Name: - Type: - the following types are currently supported: on_sensor: the trigger is sensor combo below. · injected_volume: · lost_volume: · - name of the trigger. · · USER’S GUIDE & TUTORIALS (released: Apr-14) associated to a sensor, which must be selected in the the trigger is based on the injected volume for a specific injection port. The injection port ID is specified in the group ID field below. the trigger is based on the lost volume for a specific vent. The vent ID is specified in the group ID field below. global_injected_volume: injection ports. global_lost_volume: Variable: this the trigger is based on the injected volume of all the the trigger is based on the lost volume of all the outlets. parameter is only meaningful for on_sensor type. · pressure: the resin · filling: · thickness: · temperature: pressure is sampled on the sensor. the filling factor (value between 0 and 1), is sampled on the sensor. thickness is sampled on the sensor (standard solver only). temperature is sampled on the sensor (parallel solver only). Sensor: the list of sensors currently defined in the document. Sensors should be created before defining triggers. PAM-RTM USER'S GUIDE Trigger Manager USER’S GUIDE & TUTORIALS (released: Apr-14) 174 PAM-RTM 2014 © 2014 ESI Group - Group ID: only meaningful for the injected_volume and lost_volume types. The ID of the group defining the injection port or vent. - Threshold: - Direction: indicates if the trigger is to be fired when the threshold is crossed from_below (positive slope), from_above (negative slope), or from_all (every time the critical value that will fire outcomes. It could be a pressure value or a filling factor value, depending on the variable selected. For instance, if filling is selected and a value of 1 is entered as threshold, it means that outcomes will be fired when the element on which the sensor is located is completely filled. If a pressure value of 10 000 Pa is entered, it means that outcomes will be fired when the resin pressure on the sensor becomes larger than 10 000 Pa. the threshold is crossed, regardless of the direction). the maximum number of times that the outcomes can be fired. For instance, if a pressure trigger is defined, it is possible that the pressure will increase above the threshold, which will fire the outcomes a first time, then decrease, and increase again to the threshold, firing the outcomes a second time. To avoid that enter a value of 1 for nb max release. - Nb max release: - Name: - Group ID: - Coef name: - give a meaningful name to the outcome, such as “close line 1”. the group (boundary condition) on which the coefficient will be set. · state: most of the time you will work with the state coefficient, allowing opening (coef value = 1) and closing (coef value = 0) of inlets and outlets. · pressure: forces the pressure value on an inlet (standard solver only). · flow_rate: forces the flow rate on an inlet (standard solver only). Coef value: the value that being fired. PAM-RTM USER'S GUIDE Trigger Manager will be set on a coefficient as the result of an outcome PAM-RTM 2014 © 2014 ESI Group 175 USER’S GUIDE & TUTORIALS (released: Apr-14) CURVE VIEWER The curve viewer is used to visualize simulation results on sensors. It is also used to visualize mathematical functions associated to simulation parameters, such as viscosity dα as a function of temperature and as a function of temperature, or the reaction rate dt degree of cure. Depending on the context, the curve viewer will be used to visualize functions of one or two independent variables. Importing Curves The curve viewer is opened with the View->Curve Viewer command. Notice that there is a popup menu available by right-clicking in the graphics area. Curve viewer’s popup menu Curves can be imported in the curve viewer with the Import Curves command of the popup menu. In general curves imported that way are sensor results files (see section Sensors). PAM-RTM USER'S GUIDE Curve Viewer USER’S GUIDE & TUTORIALS (released: Apr-14) 176 PAM-RTM 2014 © 2014 ESI Group Settings Plot range Plot range for a function of one variable The Plot Range tab is used to specify the range that the user wants to plot. For example, if the currently visualized function is viscosity with respect to temperature, changing the X min and X max values means changing the temperature range to visualize. PAMRTM™ will re-evaluate the function on Nb pts equally spaced in the new range and update the graph accordingly. dα with dt respect to temperature and degree of cure, the Plot Range tab has more parameters, as shown below. When functions of two variables are visualized, such as the rate of reaction PAM-RTM USER'S GUIDE Curve Viewer PAM-RTM 2014 © 2014 ESI Group 177 USER’S GUIDE & TUTORIALS (released: Apr-14) Plot range for a function of two variables Here we see that the X variable is temperature and the Y variable is alpha (degree of cure). The Plot variable dropdown list is used to select the variable displayed on the X axis of the graph. In this example, the X axis is temperature, which varies between 300 and 350 Kelvin, and five iso-alpha curves are plotted (see graph below). PAM-RTM USER'S GUIDE Curve Viewer USER’S GUIDE & TUTORIALS (released: Apr-14) 178 PAM-RTM 2014 © 2014 ESI Group Iso-alpha curves Changing the Plot variable to alpha instead of temperature would lead to the following iso-temperature curves. PAM-RTM USER'S GUIDE Curve Viewer PAM-RTM 2014 © 2014 ESI Group 179 USER’S GUIDE & TUTORIALS (released: Apr-14) Iso-temperature curves PAM-RTM USER'S GUIDE Curve Viewer USER’S GUIDE & TUTORIALS (released: Apr-14) 180 PAM-RTM 2014 © 2014 ESI Group Axis Settings Axis settings In general the X and Y axis ranges are automatically calculated from the data points to fit entirely the curves. In some situations the user may want to restrict the view, so the Auto Range parameter can be unchecked and a different range specified. Note that this changes only the viewing range, not the plot range, which means that the function is not re-evaluated. If you want to re-evaluate the function on a different range, use the Plot Range tab. PAM-RTM USER'S GUIDE Curve Viewer PAM-RTM 2014 © 2014 ESI Group 181 USER’S GUIDE & TUTORIALS (released: Apr-14) Labels Labels Graph title and labels for the X and Y axis are automatically assigned by PAM-RTM™ depending on the context. If the user doesn’t like the default labels, he can modify them with the Labels tab. This is useful for example if a screen capture of the curve viewer is needed to be included in a report and the labels are not explicit enough. Legends Legends tab PAM-RTM USER'S GUIDE Curve Viewer USER’S GUIDE & TUTORIALS (released: Apr-14) 182 PAM-RTM 2014 © 2014 ESI Group It is possible to modify the graph legends. First select the legend to be modified in the list, then enter the new text in the text field, and finally push the Apply button. Saving Images The curve viewer graphics area can be saved in an image file, which can be included later in reports. The supported image file formats are: - PNG - GIF - TIFF - JPEG - It is recommended to use the PNG format. PAM-RTM USER'S GUIDE Curve Viewer PAM-RTM 2014 © 2014 ESI Group 183 USER’S GUIDE & TUTORIALS (released: Apr-14) RUNNING THE SIMULATION FROM A COMMAND WINDOW Windows Most of the time the PAM-RTM™ solver is launched from the user interface with the start button in the simulation toolbar. In some situations however it can be useful to launch the simulation from a command window. For example you might want to launch many simulations from a batch program on your PC to have them running during the week-end. Or you might want to run a big simulation on a Linux workstation. On Windows, you will need first to identify the directory where the solver executable file pamrtm.exe is located. This can be done with the Options->Paths tab. Then open a Command Prompt window with Start->All Programs->Accessories>Command Prompt. Change directory to where the PAM-RTM™ input file (.dtf) is located, then launch the simulation by typing the full path to pamrtm.exe between quotes, as shown below. PAM-RTM USER'S GUIDE Running the Simulation from a Command Window USER’S GUIDE & TUTORIALS (released: Apr-14) 184 PAM-RTM 2014 © 2014 ESI Group Calculations using the parallel solver are also normally launched with the start button in the simulation toolbar. However if for some reason the user wants to launch a calculation from outside the user interface, the file xxx_dmp.bat can be used. You need to launch the calculation at least once from the user interface to have that file generated. To launch the calculation, simply double-click that file in the Windows Explorer, or enter “xxx_dmp.bat” in a command prompt window. That file could be easily edited to run many cases consecutively. Linux To run a simulation on Linux with the standard solver, the input files have to be prepared first with the user interface on Windows, because only the solver is available on Linux. Save the project with File->Save. Then upload the .dtf file and matching .unv file (mesh file) by FTP to your Linux workstation. Use telnet or an equivalent to connect to the Linux workstation. Type “pamrtm xxx.dtf” to launch the simulation. When it is done, download the results files x_*.unv to the PC and go back to the PAM-RTM™ user interface for post-processing. To run a simulation on Linux with the parallel solver, do the same as described above to transfer the files. Then type “pamrtmdmp xxx.dtf”. Here are optional parameters that can be passed to pamrtmdmp. pamrtmdmp [-np <#>] [-host] [-restart] [-mpiext " "] PAM-RTM USER'S GUIDE Running the Simulation from a Command Window PAM-RTM 2014 © 2014 ESI Group 185 USER’S GUIDE & TUTORIALS (released: Apr-14) -np <#>: specifies the number of processors to use on a single host. This option must not be used if a cluster configuration file is specified (see -host option). -host : specifies the name of a cluster file configuration for applications running on multiple hosts within distributed memory environment (MPI). A cluster file configuration simply lists a series of hostnames, one per line, followed by the number of processors to use on each host. -mpiext " ": pass optional arguments to mpirun program. See HP-MPI manual for the list of mpirun arguments. -restart: this option must be specified when a restart of a calculation is needed. The user must first edit file xxxp.dat and change the value of INILEV to the step number from where the calculation will restart. : input file name (.dtf). Typical commands: • pamrtmdmp –np 2 test.dtf • pamrtmdmp –host clusterfile test.dtf Here is an example of cluster file: host1 2 host2 2 host3 4 host4 6 PAM-RTM USER'S GUIDE Running the Simulation from a Command Window PAM-RTM 2014 © 2014 ESI Group 187 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS CENTRAL INJECTION The files related to this example are: - central_start.unv (starting mesh) - central.dtf + central.unv (solution) Objective This example on central injection will show you how to: - create a simulation project, - import a mesh to create groups of nodes for boundary conditions, - visualize the zones, - specify the simulation parameters for an injection based on Darcy’s law, - display the filling pattern in the cavity and the pressure field in time. Model of the Part and Physical Parameters The part analyzed here is a square plate of length 0.5 m and thickness 0.005 m with a hole of radius 0.01 m in the center, through which a resin of viscosity 0.1 Pa.s is injected. The reinforcement is isotropic. The permeability is K1 = K2 = K3 = 1E-9 m2, and the porosity 0.7. TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 188 PAM-RTM 2014 © 2014 ESI Group Mesh Import and Visualization of the Zones To launch PAM-RTM™, double-click the shortcut on the desktop, or use the shortcut in the Windows start menu (Start->Programs->PAM-SYSTEM->PAM-RTM->version>PAM-RTM). To create a new simulation, use the File->New command. This pops up the simulation type box, choose the RTM simulation type. To load the mesh provided for this example, use the File->Import->Mesh command. This pops up the Import Mesh dialog box, in which you can choose the format of the mesh file. For this example, the mesh provided is an I-DEAS Universal file. TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 189 USER’S GUIDE & TUTORIALS (released: Apr-14) After opening the file, you should see the following: The zones are groups of finite elements used to assign different material properties to different regions of the mesh. To visualize the zones defined in a mesh, select Zones in the display toolbar. This leads to the following picture, in which we can see that all the elements in this mesh are part of zone 11. TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 190 PAM-RTM 2014 © 2014 ESI Group Creation of Groups Groups of nodes or groups of faces are used to specify boundary conditions. To visualize the groups defined in a mesh, select Groups in the display toolbar. Since currently there are no groups defined in this mesh, you see nothing special. The fact that there is no color scale displayed at the left of the window is an indication that there is no group currently defined in the mesh. You can also verify this with the Groups->Info command. To create a group of nodes, you must first select some nodes. Turn on visualization of nodes by clicking the N checkbox in the toolbar. To select nodes more easily and to see more easily the groups, you might have to turn off visualization of edges (E). TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 191 USER’S GUIDE & TUTORIALS (released: Apr-14) Activate multiple picking mode with the + button in the toolbar. If you want to remove a selected node to your selection, you can activate the – button by clicking on it. Then select all the nodes around the injection hole. There is an useful command that allows you to do that in a single click on Selection->Pick Boundary, then pick one of the nodes around the injection hole. All the nodes are automatically selected. Once the nodes are selected, you can create a group with the Groups->Create command. If you are not currently in Groups visualization mode, choose Groups from the toolbar combo box to visualize the new group. You should have the following display. Save the project with the modified mesh with the File->Save As command. Give the file a different name so that you don’t overwrite the original mesh. If your .dtf file is called for example test.dtf, a mesh file called test.unv will be automatically saved in the same directory as the .dtf file. TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 192 PAM-RTM 2014 © 2014 ESI Group Simulation For this example, only the parameters that should be changed from their default value will be pointed out. In the left column, you can find all the parameters necessary for the simulation. These parameters are divided into six categories, namely: Process, Numerical, Materials, Zones, Boundary Conditions and Sensors. Double-click on Numerical to open the RTM Numerical Parameters dialog box. TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 193 USER’S GUIDE & TUTORIALS (released: Apr-14) Verify that Save Filling Factor and Save Pressure are active. Double-click Default Fabric. The following dialog box pops up. Enter an isotropic permeability of 1.10-9 m2 for K1, K2 and K3. Now, double-click Default Resin. The resin properties will appear. Set a constant viscosity of 0.1 Pa.s [1]. TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 194 PAM-RTM 2014 © 2014 ESI Group Double-click on Zone 11. Make sure that Default Fabric is assigned to it, the porosity is 0.7 and the shell thickness is 0.005 m. Right-click Boundary Conditions, select New->Pressure as type of boundary condition. Then, double-click pressure_-1. Enter the ID of the group [1] and the value of the injection pressure [2]. In this example, 1E+5 Pascals is used, so the pressure is constant and equal to one bar. Note that it is also possible to choose a piecewise linear curve in the function editor to simulate a time dependent injection pressure. It is sometimes useful to define sensors at specific locations in the cavity to sample pressure or temperature. Right-click Sensors, select Create and the dialog box Create Sensors appears. TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 195 USER’S GUIDE & TUTORIALS (released: Apr-14) Select 3 nodes (A, B and C) as shown in the following picture. You can enter directly the position of the sensor or you can select it with the Pick function. Then you click on the Create button. TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 196 PAM-RTM 2014 © 2014 ESI Group Finally, save the simulation parameters with File->Save. Note : · Whenever simulation parameters are modified, it is important to save the file before launching a new simulation (otherwise the simulation will be executed with the old set of parameters). · The simulation can be launched by clicking on the Start button [1] or by selecting Simulation->Run [2]. Post-Processing the Results To import the filling results, click on the Reload Results button [1]. It is possible to load results during the calculation. After importing scalar fields, they become available in the scalar field combo box [1]. Select Filling, then drag the time step scroll bar to visualize the filling factor step by step [2]. Alternatively you can use the arrows to visualize a scalar field step by step. You can also launch an animation by clicking the A check box [3]. Now you should have the following picture. This is the “raw” filling result of the PAM-RTM™ simulation (the filling factor is calculated in PAM-RTM™ as a constant per element scalar field). You can improve the display of the filling factor by selecting Iso in the display toolbar [1]. This will give you a smoothed scalar field. TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 197 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 198 PAM-RTM 2014 © 2014 ESI Group Another useful scalar field to visualize is Filling Times. This scalar field is used to visualize the successive positions of the flow front in time in a single picture. TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 199 USER’S GUIDE & TUTORIALS (released: Apr-14) Finally, we can have a look at the pressure field at the end of the injection, when the cavity is completely filled. TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 200 PAM-RTM 2014 © 2014 ESI Group It is important to understand in this example that, even if no vents were specified, PAM-RTM™ is able to fill completely the cavity. This is because it assumes that when no vent is specified, the injection is performed under perfect vacuum. The sensors defined are important tools to study the results. They enable the display of pressure curves in time. Right-click on the name of the sensor and select Plot. Each time you select Plot on a sensor, a curve is added to the curve viewer. This is useful to compare curves. To clear the curves currently displayed in the curve viewer, right-click in the drawing area and choose Clear. TUTORIALS Central Injection PAM-RTM 2014 © 2014 ESI Group 201 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Central Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 202 PAM-RTM 2014 © 2014 ESI Group EDGE EFFECTS – RECTANGULAR PLATE The files related to this example are: - rect_edge_start.unv (starting mesh) - rect_edge.dtf + rect_edge.unv (solution) Objective In this example, a rectangular plate is injected from one side. The plate contains a special zone along one edge, in which the resin flows more quickly. This phenomenon, quite common in RTM, is called race tracking. Creation of Groups and Visualization of Zones Create a new simulation , use File ->New command and choose the RTM simulation type. The mesh provided for this tutorial doesn’t contain any group, so the first step is to define groups of nodes for the injection and vent boundary conditions. Import the file rect_edge_start.unv with the menu File->Import->Mesh. Select Zones in the scalar field combo box [1]. Notice in the zones image that 2 zones are defined. Zone number 11 will be used for race tracking. We will assign it a material with higher permeability than the permeability of zone 9. TUTORIALS Edge Effects – Rectangular Plate PAM-RTM 2014 © 2014 ESI Group 203 USER’S GUIDE & TUTORIALS (released: Apr-14) Now we will create 2 groups of nodes, one for the pressure boundary condition on the left side of the rectangle, and one for the vent on the right side. - Click on N to activate visualization of nodes [1]. - Select Groups in the scalar field combo box to view nodes colored according to the group ID [2]. - Drag the mouse to select the nodes on the left [3]. - Choose Groups->Create. This creates a group with ID = 1. - Select the nodes on the right. - Choose Groups->Create. A group with ID = 2 is created. TUTORIALS Edge Effects – Rectangular Plate USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Edge Effects – Rectangular Plate 204 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 205 USER’S GUIDE & TUTORIALS (released: Apr-14) Simulation Double–click on Default Fabric and give the value 1.10-10 m2 to the components of the permeability tensor K1, K2, K3. Create a new reinforcement (of type fabric). Name it Runner and define its permeability to 1.10-9 m2, so the permeability of this zone will be ten times larger than the rest of the cavity. Click on Zones, verify that the material assigned to zone 9 is Default Fabric with a porosity of 0.5 and that the material of zone 11 is Runner. Give the value of 1 to the porosity of zone 11. This means that this region doesn’t contain any fibers. TUTORIALS Edge Effects – Rectangular Plate USER’S GUIDE & TUTORIALS (released: Apr-14) 206 PAM-RTM 2014 © 2014 ESI Group Note: · Zones used for race tracking have a porosity of 1. However a reinforcement has to be assigned to these zones even if they don’t contain any fibers. Right-click on Boundary Conditions, select Pressure as type of boundary condition. Enter the number of the group 1 and set a constant injection pressure of 1.105 Pa. Set group 2 to type Vent and set its pressure to zero. Save the simulation parameters file with File->Save and give it the name my_edge.dtf. Launch the simulation with the Start button. Visualization of Results Import the filling results by clicking on Reload Results button. Choose Filling in the scalar field toolbar and click on the A check box to animate the filling results. Then have a look at the pressure field. An interesting visualization feature is the Filling_Times scalar field which shows in only one picture the evolution of the resin front during the injection. You should have the following picture. Notice how the resin flows more easily along the top edge. TUTORIALS Edge Effects – Rectangular Plate PAM-RTM 2014 © 2014 ESI Group 207 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Edge Effects – Rectangular Plate USER’S GUIDE & TUTORIALS (released: Apr-14) 208 PAM-RTM 2014 © 2014 ESI Group EDGE EFFECTS – COMPLEX SHAPE The files related to this example are: - complex_edge_start.unv (starting mesh) - complex_edge.dtf + complex_edge.unv (solution) Objective This example is an extension of the previous case. The mesh provided with this example was created from the drawing below. We don’t give the details of how to create such a geometry. We assume that the PAM-RTM™ user already knows a CAD software and mesh generator. The most time consuming task in creating this geometry is the definition of the race tracking zones. A thin zone of two millimeters width must be added along the edges of the cavity, in which the resin will flow more quickly. Drawing and dimensions of the plate. Visualization of Groups and Zones The pictures below show the groups and the zones defined in the mesh file. TUTORIALS Edge Effects – Complex Shape PAM-RTM 2014 © 2014 ESI Group 209 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Edge Effects – Complex Shape USER’S GUIDE & TUTORIALS (released: Apr-14) 210 PAM-RTM 2014 © 2014 ESI Group Simulation This section describes the parameters required to carry out this simulation: General Simulation Parameters Simulation type: RTM Geometry file: complex_edge_start.unv Materials The equivalent permeability of an empty channel of diameter D for a Poiseuille flow is: K = D2/12 Krunner = (2mm)2/12 = 3,3 10-7 m2 This is the permeability we will use here for the runner all around the part. Set the following properties : - Resin: constant viscosity at 0.2 Pa.s - Default fabric: K1 = K2 = 3 10-9 m2 K3 = 1 10-9 m2 - Runner: K1 = K2 = K3 = 3,3 10-7 m2 Zones Define the central zone (the one with the largest area) with the Default Fabric. Its porosity is 0.6 and thickness 0.003 m. For zone 2, the material to select is Runner with a thickness of 0.003 m and a porosity of 1. Boundary Conditions Define group 1 as an injection boundary condition of type Pressure with a constant injection pressure of 3 105 Pa. Define group 2 as a vent. Simulation Save the simulation parameters file under the name my_complex_edge.dtf and launch the simulation. Here are the filling and pressure results at the end of injection. TUTORIALS Edge Effects – Complex Shape PAM-RTM 2014 © 2014 ESI Group 211 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Edge Effects – Complex Shape USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Edge Effects – Complex Shape 212 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 213 USER’S GUIDE & TUTORIALS (released: Apr-14) FIBER ORIENTATIONS The following files will be used: - deltoid_start.unv (starting mesh) - deltoid.dtf + deltoid.unv (solution) Objective This tutorial shows how to specify fiber orientations in a T-junction. Test Part The length of the part is 0.3 m. Two layers of reinforcement of thicknesses t1 and t2 are considered. The total height is h=0.2 m. The injection is performed through the left wall with a resin of viscosity 0.02 Pa.s. Special attention should be paid to the permeability values in the three directions K1, K2 and K3. Two materials will be used: one fabric in the deltoid zone with a lower isotropic permeability, and another fabric in the other zones. Fiber Orientations Begin by creating a new RTM simulation and import the mesh file deltoid_start.unv. The orientations of the permeability tensor can now be defined. To do so, it is important to visualize the different zones. In the display toolbar, select Zones, activate Edges and Faces, deactivate Nodes. TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 214 PAM-RTM 2014 © 2014 ESI Group Here is what will appear on the screen: The fiber orientations must be specified in every zone, except in zone 28 (middle zone of the deltoid), where it is not necessary since permeability is isotropic in this region. The simpler zones, where the fibers are oriented along x and y as principal axes, will be defined first. We will first select the elements on which we want to specify orientations using zone selection. Set the selection filter in the main toolbar to Face (or use Selection->Face from the menu). There are several ways to select a zone : - Click Selection->Zone ID [1], a dialog box pops up enabling to enter the zone ID. TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 215 USER’S GUIDE & TUTORIALS (released: Apr-14) - Click Selection-> Pick zone [2] and pick one element of the zone to select. - Right-click on zone_ID and choose Select. TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 216 PAM-RTM 2014 © 2014 ESI Group Select elements in zones 26, 34 and 36 (horizontal parts). Then, open the Material Orientations dialog box (Mesh->Orientations->Set Vectors). TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 217 USER’S GUIDE & TUTORIALS (released: Apr-14) Define K1 (1,0,0) and click the Set K1 button. This permeability will be defined for each of the selected zones. Define K2 (0,1,0) and click the Set K2 button. Close the window by clicking the Close button. Then clear the current selection (Selection->Unselect All). In the same way, select the elements in zone 38 (vertical part). Open the Materials Orientations dialog box and define K1 (0,1,0) and K2 (1,0,0). We are now ready to work on the two curved sections. Clear all the selections with Selection->Unselect All. Select the desired zone, say zone 32 (one of the two curved zones). Then in the display toolbar, click the N button to activate node display. Next, in the Selection menu, choose Nodes. TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 218 PAM-RTM 2014 © 2014 ESI Group Using the mouse and clicking on the nodes of interest, you can select the nodes that will define the orientation of the fibers. They will appear in red once the selection is made. The order of selection is important. Select them from left to right or from right to left. As soon as this step is completed, the fiber orientations can be defined. First of all, in the selection menu, choose Face, and select zone 32. Set the current working direction as K1 with Mesh->Orientations->K1 [1]. From the same menu, select Set K From Selected Nodes (this should be understood as Set K1 From Selected Nodes). The selected elements are projected on a curve constructed from the selected nodes. The tangent vector at the projected point indicates the orientation of the fibers. Permeability K1 is now defined in zone 32. Permeability K2 remains to be specified from the menu Mesh->Orientations. After having selected K2 [1], choose the submenu Set K Orthogonal (meaning Set K2 Orthogonal to K1). TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 219 USER’S GUIDE & TUTORIALS (released: Apr-14) Clear all current selections and restart the same procedure with elements of zone 30. Once completed, the orientations of the fibers appear as follows: To view orientations, select View->Orientations->K1 Only. TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 220 PAM-RTM 2014 © 2014 ESI Group Now, set the permeability of the reinforcement. Double-click on default Fabric and click on the … button [1]. This opens the Function Editor dialog box, which lets you assign a curve or a constant value to the parameter: TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 221 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 222 PAM-RTM 2014 © 2014 ESI Group Set the permeability for the Default Fabric to K1=1 10-11 K2=1 10-12 K3=1 10-11 Create a new Fabric (Material->New->Fabric), name it deltoid and set the isotropic permeability to K1=K2=K3=1 10-13 TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 223 USER’S GUIDE & TUTORIALS (released: Apr-14) The following table summarizes the permeability assigned to each zone. Zone 38 Zone 32 Zone 30 Zone 36 Zone 34 Zone 26 Zone 28 Zone N° Material K1 K2 K3 Porosity 26 Default fabric 1E-11 1E-12 1E-11 0.5 28 Deltoid 1E-13 1E-13 1E-13 0.4 30 Default fabric 1E-11 1E-12 1E-11 0.5 32 Default fabric 1E-11 1E-12 1E-11 0.5 34 Default fabric 1E-11 1E-12 1E-11 0.5 36 Default fabric 1E-11 1E-12 1E-11 0.5 38 Default fabric 1E-11 1E-12 1E-11 0.5 For every zone, you must also specify the porosity of the reinforcement (see previous table) and its thickness (0.005 m). Define properties of the resin, set a constant viscosity of 0.02 Pa.s. The boundary conditions still remain to be defined. Three groups are available. Assign Pressure to the one that corresponds to the injection line (left side). Enter a constant pressure value of 2 105 Pa. Then, define the other two lines as vents. Now choose File->Save and run the simulation. Note: · It is important to save this file before launching a simulation, otherwise the changes you made to the simulation parameters won’t be used in the simulation. TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 224 PAM-RTM 2014 © 2014 ESI Group Visualizing the Simulation Results Many post-processing parameters can be changed in the Post-processing dialog box by selecting View –> Post-Processing. After loading the simulation results, choose the Filling option in the drop-down list to visualize the evolution of injection. Then by sliding the Time Step control arrow in the tool bar, the filling of the mold is displayed in time. By clicking on the button A (animation), an animated display of mold filling is activated. The animation speed can be modified by changing the Loop Time field in the Post-processing dialog box. To get a smooth injection flow front, select the Type Iso in the drop-down list. The number of colors may be modified in the Nb levels field in the Post-processing dialog box. TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 225 USER’S GUIDE & TUTORIALS (released: Apr-14) The figure below shows the different positions of the flow front in time in the part. TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 226 PAM-RTM 2014 © 2014 ESI Group The following figures show sequentially how the mold is filled: The injection is performed from the left side of the part. The lower permeability in the central zone of the junction delays the flow front in that zone. The pressure field can also be visualized during the injection. Select Pressure in the drop-down list in the display toolbar. It is sometimes useful to visualize the resin front on top of another scalar field such as the pressure or temperature field. To do so, select File–> Import–> Scalar Fields –> PAMRTM Flow Front (.front)… , then under the Import PAM-RTM Flow Front dialog box, select the flow front file and click Open. TUTORIALS Fiber Orientations PAM-RTM 2014 © 2014 ESI Group 227 USER’S GUIDE & TUTORIALS (released: Apr-14) The following image is displayed, in which the flow front appears as a white line. This is the raw position of the flow front, without any smoothing. On one side of the flow front, the elements are completely saturated (filling factor = 1), while on the other side elements are partially saturated or empty (0 <= filling factor < 1). TUTORIALS Fiber Orientations USER’S GUIDE & TUTORIALS (released: Apr-14) 228 PAM-RTM 2014 © 2014 ESI Group COMPARISON 2D – 2.5D – 3D The following files are used in this example. - comparison_2D_start.unv, comparison_25D_start.unv, comparison_3D_start.unv - comparison_2D.dtf - (starting mesh) + comparison_2D.unv (solution for 2D) comparison_25D_1.dtf, comparison_25D_2.dtf, 2.5D) comparison_3D_1.dtf, comparison_3D_2.dtf, + comparison_25D.unv (solution for + comparison_3D.unv (solution for 3D) Introduction Description of the Part This example describes the results obtained for a part whose dimensions are specified in the figure below: The injection is performed at a constant pressure of 2 bars from each extremity of the part as illustrated on the figure below: TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 229 USER’S GUIDE & TUTORIALS (released: Apr-14) Objectives of the Analysis The objectives of this analysis is to study the position of the resin front and to compare the results obtained from three types of mesh: - 2D plane mesh of triangles - 2.5D surface mesh (thin shell) with triangular shell elements - 3D solid mesh of tetrahedrons TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) 230 PAM-RTM 2014 © 2014 ESI Group Plane mesh Description of a Typical Rib Junction The permeability of the reinforcement is K1 = K2 =K3 = 1.10-9 m2 and the porosity is φ = 0.5. The rib junction is constructed with unidirectional fibers to fill the internal volume between the two top folded plies and the inferior layers in order to create the T shape. The permeability of the reinforcement in the rib junction (shaded area in the figure below) is K1 = K2 = K3 = 1.10-10 m2. TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 231 USER’S GUIDE & TUTORIALS (released: Apr-14) Typical rib junction (T shape) Zones of the Part The analysis was carried out in order to compare the results between a 2D simulation with analyses performed with shell (2.5D) and solid (3D) elements. The following figures show the different permeability zones for each type of simulation. (a) 2D zones TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) 232 PAM-RTM 2014 © 2014 ESI Group Zones for the three types of mesh: We can immediately notice several differences. Indeed, in the surface simulation, there is no central zone at the junction. The zones used in the 2D simulation do not consider the curvature of the part. These topics will be discussed later. Injection Strategies The following table indicates the injection pressure used for each experiment. TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 233 USER’S GUIDE & TUTORIALS (released: Apr-14) Simulation Pinj 1 Pinj 2 2D 2 bars 2 bars 2.5 D/1 2 bars 2 bars 2.5 D/2 2 bars 2.3 bars 3D 2 bars 2 bars The following figures show the groups of nodes that define the injection boundary conditions: TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Comparison 2D – 2.5D – 3D 234 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 235 USER’S GUIDE & TUTORIALS (released: Apr-14) Simulation Results Filling Times The first interesting point to verify here is the injection time required to fill the mold for each type of analysis. The filling times are in fact very similar, between 19.9 and 21.3 seconds for the three simulations. This demonstrates the consistency between the different options offered by the software. TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Comparison 2D – 2.5D – 3D 236 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 237 USER’S GUIDE & TUTORIALS (released: Apr-14) Special Effects in the Rib Junction However, several differences exist between the different types of simulation. The 2D simulation shows the details of the filling in the T junction, which is naturally not possible with the 2.5D results. An air bubble is formed in the T junction as illustrated below by a series of filling results at different injection times. Although a 2D simulation allows observation of local effects, it does not give a 3D picture of mold filling. As a matter of fact, the whole geometry of the part has an influence on the filling pattern. TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) 238 PAM-RTM 2014 © 2014 ESI Group This air bubble could possibly be removed by the pressure field up to the vent. Note that this is no longer a problem if the injection is performed under vacuum. Convergent and Divergent Flows A surface simulation (2.5D) allows to compare the injection pressure with a 2D analysis. Note that the resin front does not merge near the rib like in the 2D analysis, but on the right panel, where the flow is divergent. As a matter of fact, the resin flow converges in the left panel and diverges in the right panel. This difference in geometry accelerates the resin flow in the convergent geometry as shown in the figure below: TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 239 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) 240 PAM-RTM 2014 © 2014 ESI Group Although the injection pressure is the same on both sides, the left panel fills up faster than the right one. The surface simulation, and not the plane simulation, could show this phenomenon, which is due to resin flows in convergent versus divergent geometries. Modification of the Injection Pressure on one Side In order to merge the two resin fronts in the center of the part, it is possible to inject from one side at 2 bars and from the other at 2.3 bars. The flow fronts merge then right in the middle of the part at the rib connection as illustrated in the figures below: TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 241 USER’S GUIDE & TUTORIALS (released: Apr-14) The selection of two different injection pressures permits to merge the resin fronts in the center of the part, i.e., directly at the rib junction The need to inject with two different pressures would not have appeared without performing a surface simulation. 3D Solid Simulations Although surface simulations (2.5D analysis) provide a global vision on the filling of the part, no local effects are shown such as how the two incoming resin fronts merge in the T junction for example (where it was seen that air bubbles form). 3D solid simulations visualize such problems. Both global and local effects will appear at the same time: convergent and divergent flux phenomena, as well as air bubbles in the rib junction. However, the time required to model the geometry of the part, generate the 3D mesh and especially, the calculation time to simulate the injection, becomes much more important. TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) 242 PAM-RTM 2014 © 2014 ESI Group Geometry related effects can be studied with a 3D simulation, which provide a global vision. As shown in the figure on the left, it is necessary to inject at a higher pressure so that the resin fronts will merge at the center of the part. Pressure Field in the Cavity Finally, as illustrated by the images of next page, the analysis of the pressure field in the cavity during the injection does not show much difference between the three types of simulations considered here. TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 243 USER’S GUIDE & TUTORIALS (released: Apr-14) Conclusion In conclusion, a 3D simulation with solid elements allows observation of global and local effects related to the geometry of the part. A surface simulation (2.5D) provides a global vision at a reduced cost while a 2D simulation in a section of the part shows only local effects. The advantage of a 2D simulation is the much reduced calculation time. TUTORIALS Comparison 2D – 2.5D – 3D USER’S GUIDE & TUTORIALS (released: Apr-14) 244 PAM-RTM 2014 © 2014 ESI Group 3D simulations require a much larger number of elements to perform the calculations, which causes the calculation times to increase dramatically. The following table compares the numbers of elements used in this example with the corresponding calculation times. The simulations were run on a dual processor Pentium 3 700 MHz PC. Simulation Number of elements Simulation time 2D 3084 triangles 5 min., 8 s. 2.5D 3979 triangles 1 min, 25 s. 3D 35137 tetrahedrons 100 min. TUTORIALS Comparison 2D – 2.5D – 3D PAM-RTM 2014 © 2014 ESI Group 245 USER’S GUIDE & TUTORIALS (released: Apr-14) AIR ENTRAPMENT The files related to this example are: - air_trap_start.unv (starting mesh) - air_trap.dtf + air_trap.unv (solution) Visualization of Groups and Orientations In this tutorial, we do a central injection in a fabric with anisotropic permeability. Here is a picture of the K1 principal permeability direction. We use this simple example to demonstrate the air entrapment feature of PAMRTM™. We want to force creation of an air trap in the bottom right corner by closing vents shortly after beginning of injection. Only the top left vent stays open during the complete simulation. TUTORIALS Air Entrapment USER’S GUIDE & TUTORIALS (released: Apr-14) 246 These are the parameters that were used for this simulation: - Input geometry file: air_trap_start.unv - Simulation type: RTM - Air entrapment: active [1] - Resin viscosity: 0.1 Pa.s - Permeability: K1 = 1E-9 m2, K2 = 1E-10 m2 - Porosity: 0.5 - Injection pressure: 2E5 Pa - Vents’ pressure: 1E5 Pa - Vent 2 stays open during the complete simulation (State = 1) - Vents 3 and 5 closed at 85 s. - Vent 4 closed at 120 s TUTORIALS Air Entrapment PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 247 USER’S GUIDE & TUTORIALS (released: Apr-14) To close a vent at a given time, open the Function Editor dialog box for the state parameter of the boundary condition, and define a piecewise linear function as shown below: The anisotropic fabric leads to an elliptical flow front. TUTORIALS Air Entrapment USER’S GUIDE & TUTORIALS (released: Apr-14) 248 PAM-RTM 2014 © 2014 ESI Group To avoid air traps in the bottom left and top right corners, the vents are closed a short time after the resin reaches them (t = 85 s.). The bottom right vent is kept open a little longer. When it is closed (t = 120 s.), an air trap is detected by PAM-RTM™. The top left vent stays open during the complete simulation, that’s why there is only one air trap detected. As soon as the air trap is detected, the pressure starts to increase in it. The law of perfect gases Pressure * Volume = constant is used to manage the pressure increase as the volume of the air trap changes. After some time, the pressure in the air trap becomes very close to the injection pressure, which means that the pressure gradient is very small and the resin can’t move. The simulation stops with some elements that are not filled. TUTORIALS Air Entrapment PAM-RTM 2014 © 2014 ESI Group 249 USER’S GUIDE & TUTORIALS (released: Apr-14) The pressure specified in PAM-RTM™ is absolute pressure. For the air entrapment option to work correctly, the vent pressure must be positive and not zero. In this example, the vent is initially open and its pressure is 1E5 Pa (1 bar). The injection pressure is 2 bars, so there is 1 bar pressure difference between the injection point and the flow front. When the air trap is detected, its pressure is the same as the initial cavity pressure (pressure on the vent), and it will rise as the air trap gets smaller. You can visualize the flow front position on top of any scalar field by loading the flow front file (extension .front) with File->Import->Scalar Fields->PAM-RTM Flow Front. The flow front is displayed as a white line in the following pressure images. Notice the pressure at the bottom left and top right corners. This “strange” pressure field comes from the fact that the resin has reached the top left corner where the vent is still open, so the pressure stays fixed at 1 bar. The last pressure image shows that the pressure in the air trap at the end of the simulation is the same as the injection pressure. TUTORIALS Air Entrapment USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Air Entrapment 250 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 251 USER’S GUIDE & TUTORIALS (released: Apr-14) VACUUM ASSISTED RESIN INFUSION (VARI) The following files will be used: - vari_start.unv (starting mesh) - vari.dtf + vari.unv (solution) Objectives This tutorial shows how to specify the parameters for a VARI simulation. The postfilling, leading to the final thickness of the part calculation, after the injection port has been closed will also be simulated. Two cases will be run, one where vents will stay open, and the other one where vents will be closed. 1m 1.5 m 0.38 m Top View Side View Mesh Modification Create a new VARI simulation with File->New and import the mesh file vari_start.unv. The mesh provided for this tutorial does not have an injection point. We will create one for central injection. To define an injection point, open the Mesh Injection Point dialog box (Mesh -> Remesh ->Injection Point). TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 252 PAM-RTM 2014 © 2014 ESI Group PAM-RTM™ asks if you want to split quads into triangles. Choose yes. The remeshing tools work only on mesh of triangles. Enter the coordinates of the center point (0, -0.385, 0) and set the radius at 0.05, then apply and close the window. The modified mesh appears as follows: TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group 253 USER’S GUIDE & TUTORIALS (released: Apr-14) Create three sensors by picking approximately points A, B and C, or enter the exact coordinates of the sensors as shown above. Simulation This section describes the parameters required to carry out this simulation: Double-click on Process in the model explorer to open the VARI Process dialog box. In the VARI tab, set the External pressure at 1.105 Pa. Overfilling is activated by checking Continue overfilling box, and the duration of Overfilling is set to 500s. The number of numerical steps is set to 50. That will allow the simulation to continue after complete filling of the part until reaching a mechanical equilibrium. In the explorer, double-click on Numerical to open the VARI Numerical Parameters dialog box and be sure that Save filling factor, Save pressure, Save thickness, Save permeability and Save porosity are active. TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 254 PAM-RTM 2014 © 2014 ESI Group Orientation No orientation is defined on the mesh. It will be defined with projection method. First select all the elements, then use Mesh->Orientation->Project Vectors to project X as K1. Then set, K2 orthogonal to K1, Mesh->Orientation->Set K Orthogonal. Materials Set the resin and the fabric properties as shown below. Resin - Constant viscosity = 0.1 Pa.s - Density = 1083 kg/m3 Fabric Double-click the Default Fabric in the explorer to open the Fabric Properties dialog box. To set the permeability K1, open the Function Editor by clicking the button beside -8 K1. Select the Exponential function, then set A = 2.2 10 and B = -11.57. TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group 255 USER’S GUIDE & TUTORIALS (released: Apr-14) 2 3 1 The permeability curve can be visualized by pushing the View button [1]. TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 256 PAM-RTM 2014 © 2014 ESI Group Instead of entering the coefficients of the exponential curve again for K2, you can use the Copy to Function Pool functionality. Push the Copy to Function Pool button [2], and then give a name to the curve, such as perm_vf. Next in the function editor of Permeability K2, you just have to click on Get From Function Pool [3] and select perm_vf to get the curve that was defined for K1. Note that the functions stored in the function pool are available until you close PAM-RTM™. The function pool is shared by all open documents. One of the most important parameters for VARI simulation is the compressibility curve of the reinforcement. Double-click Default Fabric in the explorer. In the Compressibility tab, choose the Pressure-Fiber Content curve format in the drop-down list. TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group 257 USER’S GUIDE & TUTORIALS (released: Apr-14) Push the Compressibility Curve button to define the curve. Choose a power law and set A = 1.7 1011 and B = 7.6 in the Function Editor dialog box. The compressibility curve is shown below. TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 258 PAM-RTM 2014 © 2014 ESI Group Finally set natural thickness to 0.009 m and superficial density to 0.7 kg.m-2 in the Fabric Properties dialog box. The natural thickness of the fabric corresponds to the zero pressure in the compressibility curve. TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group 259 USER’S GUIDE & TUTORIALS (released: Apr-14) Zones There is only one zone defined in this mesh. Double-click Zone_2 in the explorer, associate Default Fabric to it and set its porosity as 0.5 and its thickness as 0.005 m. Note · The thickness value specified in the zone is only used to initialize the calculation. PAM-RTM™ will calculate the actual thickness from the compressibility curve and the external pressure. It is important to set the initial thickness of zones to some value inside the definition range of the compressibility curve. Normally half the natural thickness of the reinforcement should be a good initial thickness. · If the specified material and process parameters are such that at some point in the simulation the thickness of the reinforcement becomes larger than its natural thickness, the simulation is not valid. Boundary Conditions When the injection point was created with the remeshing tool, a group was automatically created (ID=1) with the nodes around the injection hole. Now you need to associate a boundary condition to this group. Click on Boundary Conditions in the explorer with the right mouse button and choose New->Pressure. Verify that the injection pressure is 1.105 Pa. The full boundary of the injected part will be specified as a vent. You can easily select all the nodes on the boundary. Use Selection->Pick Boundary, then pick a node on the boundary you want to select. Use Groups->Create to create a group with the selected nodes. Associate a Vent boundary condition to this group and make sure that the vent pressure is zero. The groups are shown below. TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 260 PAM-RTM 2014 © 2014 ESI Group Save the PAM-RTM™ document and launch the simulation. Post-Processing It can be seen in log file that the simulation is split in two phases: filling then overfilling. TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group 261 USER’S GUIDE & TUTORIALS (released: Apr-14) The images below show the segmented filling patterns and the thickness field at the end of filling. The thickness evolution in time was plotted on the 3 sensors at positions A,B and C on picture below. B C A TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 262 Thickness evolution during filling Thickness evolution after filling TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 263 USER’S GUIDE & TUTORIALS (released: Apr-14) Second case with closing of the vent A modification of the set-up is made so that vent is closed at the end of the filling, in the same time as injection stops. The first simulation showed that filling lasts 263s. The modification of set-up is so that injection port and vent are closed after 264s. State functions for each boundary condition are set like the function below. Behavior is modified after the end of filling as the thickness value at the end of the postfilling and thickness curve show. TUTORIALS Vacuum Assisted Resin Infusion (vari) USER’S GUIDE & TUTORIALS (released: Apr-14) 264 PAM-RTM 2014 © 2014 ESI Group Thickness at the end of over-filling phase. Thickness evolution after filling Final thickness is 5.46mm compared to 4.6mm in the case of opened vent. Conclusion This tutorial showed the set-up of infusion simulation (VARI model), and the computation of final thickness after the complete filling of the part and mechanical equilibrium is reached. TUTORIALS Vacuum Assisted Resin Infusion (vari) PAM-RTM 2014 © 2014 ESI Group 265 USER’S GUIDE & TUTORIALS (released: Apr-14) LANDING GEAR The following files are used in this example. - landing_start.unv (starting mesh) - landing_1.dtf, landing_2.dtf; + landing.unv (solution) Introduction In PAM-RTM™ simulations, complex parts can be modeled with shell or solid elements. Different zones must be defined, the type of materials contained in the cavity must be specified (metallic insert, foam…) as well as the properties of the fibrous reinforcement (orientations and values of the permeability tensor). Numerical simulation aims to assist users to understand the progression of the resin flow during the injection. It helps to avoid problems such as air entrapments. It allows also to compare different injection strategies in order to find the best one, for example the one with the shortest cycle time. Non isothermal simulations study the coupling between the resin flow, temperature and curing. Landing gear TUTORIALS Landing Gear USER’S GUIDE & TUTORIALS (released: Apr-14) 266 PAM-RTM 2014 © 2014 ESI Group Analysis of a Landing Gear The landing gear of a small touring airplane is analyzed in this example. As demonstrated on the picture, the landing gear is located on the front part of the airplane and is symmetric along its central axis. If the injection is performed from the center or from the two extremities, because of the symmetry only half of the part needs to be simulated. This example is important because it compares the effect of convergent versus divergent flows and illustrates how convergent resin flows are systematically accelerated in restrictions. Two injection scenarios at constant pressure will be considered here for half of the part. The first test consists of injecting the resin from two injection ports located at the center of the part as shown in the figure below. The vents are located at both extremities at the positions of the wheels. In the second test, the resin is injected from both extremities, the vents being located in the center of the part. TUTORIALS Landing Gear PAM-RTM 2014 © 2014 ESI Group 267 USER’S GUIDE & TUTORIALS (released: Apr-14) This composite part is normally made of several materials. It contains a metallic insert at its extremities for the installation of the wheels. The center of the part is an impermeable foam. Since these are non-permeable inserts and since we are only doing an isothermal simulation, it is not necessary to mesh these inserts. It is important to note that if you decide to mesh the non-permeable zones, the mold material of PAM-RTM™ must be assigned to these zones. The mesh has been generated with I-DEAS. It is shown below. TUTORIALS Landing Gear USER’S GUIDE & TUTORIALS (released: Apr-14) 268 PAM-RTM 2014 © 2014 ESI Group Analysis of Simulation Results The landing gear has been simulated for both injection scenarios. The two injections were performed at constant pressure from the two extremities (case 1) or from the center of the part (case 2). The goal is to determine the best injection strategy to produce the part and avoid errors in the design of the mold. Let us examine the injection process in more detail. When the injection is performed from the center (first strategy), no particular difficulties appear. However when the part is injected with the second strategy, an air trap appears near the vents. This shows that the air vents are not correctly positioned. In order to correct the problem, the air vents should be positioned on the side of the part, exactly where the air traps appear. The air trap is created in this example because of the divergent flux during the injection. This phenomenon (divergent flux) does not only create an unwanted air bubble, but it also increases the injection time significantly. The successive positions of the resin front in time are displayed next for the two injection strategies considered. For a constant pressure injection, the first injection strategy gives a much lower injection time compared to the second. Indeed, the first strategy enables to fill the mold in 134 seconds, while it takes 234 seconds for the second strategy. This difference is caused by the shape of the part. In the first case, the resin flux is convergent, which has the effect of accelerating the displacement velocity of the resin in the restriction, whereas in the second case a divergent flux is obtained. TUTORIALS Landing Gear PAM-RTM 2014 © 2014 ESI Group 269 USER’S GUIDE & TUTORIALS (released: Apr-14) Conclusion The landing gear design information is a good example that demonstrates the importance of numerical simulation, appropriately provided to mold designers. Note that mistakes can be very expensive to repair once the mold is made. The simulation permits to predict where air bubbles might be created, which has a direct effect on the mechanical properties of the part. It is possible to prevent the formation of air entrapments by changing the position of the vents. In this particular case, the vents will be placed on the side of the part and not on top of it. Finally, the simulation allows to optimize the cycle time. Thus, in this analysis, the first strategy of injection proves to be the best since it allows to shorten the filling cycle and avoid the creation of air entrapments. In conclusion, numerical simulation allows to design a mold rapidly and efficiently while avoiding some expensive modifications once the mold is built. TUTORIALS Landing Gear USER’S GUIDE & TUTORIALS (released: Apr-14) 270 PAM-RTM 2014 © 2014 ESI Group MESH EXTRUSION The following files are used in this example. - extrude_start.unv (starting mesh) - extrude.dtf + extrude.unv (solution) Objectives The goal of this tutorial is to show how a surface mesh can be extruded with layers of different thickness and materials. A flow enhancing layer, such as the one found in the VARTM process, is used on top of the fiber preform. The new prismatic element is used directly to avoid splitting into tetrahedra. Mesh Extrusion Begin by creating a new RTM simulation, then import the mesh file extrude_start.unv. You should have the following. Verify that this mesh contains orientations with View > Orientations > K1 Only. Notice that the fiber directions F1 and F2 (actually K1 and K2) are not perfectly orthogonal. This can be seen by activating the Shear_Angle in the main toolbar, which shows angles of about 2 degrees. This mesh was actually oriented using PAM-QUIKFORM. TUTORIALS Mesh Extrusion PAM-RTM 2014 © 2014 ESI Group 271 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Mesh Extrusion USER’S GUIDE & TUTORIALS (released: Apr-14) 272 PAM-RTM 2014 © 2014 ESI Group The goal is to generate a solid mesh made of 5 layers: 0, +45, -45, 90, and a flow media on top. The first step is to create materials for the fiber reinforcement and the flow media. The same material will be used for the 4 plies. The fiber reinforcement has k1 three times larger than k2. The permeability of the flow media is ten times larger than k1. After creating the materials, you should have the following in the document’s tree. Notice that we use the same permeability k3 for the reinforcement and the flow media. This is important to avoid numerical problems. The thickness of the plies is set to 0.025 m. It is exaggerated for the purpose of this tutorial, to see the flow better through thickness. The thickness of the flow media is much thinner, 0.003 m. Don’t forget to set the angle of each ply. The angle of the flow media is not important since its planar permeability is isotropic. After creating the laminate, you should have the following. TUTORIALS Mesh Extrusion PAM-RTM 2014 © 2014 ESI Group 273 USER’S GUIDE & TUTORIALS (released: Apr-14) Before performing extrusion, it is important to verify that the normal vectors a pointing in the right direction (View > Normal Vectors). Here we would like the mesh to be extruded in the opposite direction. To reverse the normal vectors, we first select all the elements with Selection > Element and Selection > Select All. Then we use Mesh > Cleanup > Reverse Normals. TUTORIALS Mesh Extrusion USER’S GUIDE & TUTORIALS (released: Apr-14) 274 PAM-RTM 2014 © 2014 ESI Group Once the normal vectors have been reversed, open the mesh extrusion dialog box with Mesh > Transform > Extrude. Check the Use laminate option (meaning that parameters in the Simple extrusion area are completely ignored), select your laminate in the dropdown list, and select Orientation from ply angles so that the orientation of each element is set as the orientation of the corresponding element in the first layer, rotated by the ply’s angle. The Extrude Mesh dialog box is shown below. Push the OK button to launch mesh generation. You should have the following. Notice the top layer, very thin compared to the other layers. This is the layer used as the flow media. TUTORIALS Mesh Extrusion PAM-RTM 2014 © 2014 ESI Group 275 USER’S GUIDE & TUTORIALS (released: Apr-14) Extruded mesh Zoom on the layers TUTORIALS Mesh Extrusion USER’S GUIDE & TUTORIALS (released: Apr-14) 276 PAM-RTM 2014 © 2014 ESI Group The extrusion command automatically generates a zone for each layer in the document’s tree. Each zone is linked to the corresponding ply material. The thickness of each zone is not important since we are working with solid elements. The porosity of each zone is also set from the plies. To verify that the orientations are correctly set, use the View > Zones Visibility command. For example, hide all layers and show only zone 21. Then show K1 vectors with View > Orientations > K1 Only. You should have the following picture, correctly showing orientation vectors at –45 degrees. TUTORIALS Mesh Extrusion PAM-RTM 2014 © 2014 ESI Group 277 USER’S GUIDE & TUTORIALS (released: Apr-14) Process and Numerical Parameters For the boundary conditions, create groups of faces as shown below. We inject from 2 faces directly in the high permeability layer. The vent is at the bottom of the opposite side. Set the injection pressure to 1 bar, and keep the default zero bar on the vent. Location of the inlet TUTORIALS Mesh Extrusion USER’S GUIDE & TUTORIALS (released: Apr-14) 278 Group of faces for the inlet Group of faces for the outlet TUTORIALS Mesh Extrusion PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 279 USER’S GUIDE & TUTORIALS (released: Apr-14) Launching the Simulation and Post-Processing Save the document with File->Save and launch the simulation. Segmented filling result The segmented filling image clearly shows the effect of the flow media. Since the permeability of that layer is much higher, the resin almost completely fills that layer before starting to flow through the thickness of the part. TUTORIALS Mesh Extrusion USER’S GUIDE & TUTORIALS (released: Apr-14) 280 PAM-RTM 2014 © 2014 ESI Group NON-ISOTHERMAL INJECTION The files related to this example are: - non_iso_fil_start.unv (starting mesh) - non_iso_fil_1.dtf, non_iso_fil_2.dtf, non_iso_fil_3.dtf, + non_iso_fil.unv (solution) Objective of the Analysis This example will show you how to: - Perform a non-isothermal filling simulation, - Study the effects of temperature on the injection of resin. Geometry Description It is possible with PAM-RTM™ to simulate the injection and at the same time take into account thermal effects. The part that will be simulated in this example is shown below. It is an extruded panel of variable thickness. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 281 USER’S GUIDE & TUTORIALS (released: Apr-14) Visualization of Groups Create a new simulation of type Heated RTM (File->New) and import the mesh file non_iso_fil_start.unv. Then visualize groups of nodes. Groups at the extremity of the part will model the injection port (dark blue) and vent (light blue), groups on the top and bottom of the part (11 and 12) will be used to set the heating boundary conditions on temperature. Simulation Parameters Open the Resin Properties dialog box (doucle-click on Default Resin). Enter the resin parameters as shown below: TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 282 PAM-RTM 2014 © 2014 ESI Group - Resin Name: Vinylester - Density = 1083 Kg/m3 - Viscosity: a viscosity function relates viscosity with temperature and the degree of cure. Select the Viscosity_02 model: f (= x, y ) c0e C1 x c × 2 c2 − y C3 +C4 × y C0 = 1.10-7 C1 = 5000 C2 = 0.4 C3 = 0.75 C4 = 0.35 Choose in the Model drop down list f(temperature, alpha) and open the Function Editor (click on the … button), select the function Viscosity_02 and set its parameters. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 283 USER’S GUIDE & TUTORIALS (released: Apr-14) To visualize the viscosity function, push the View button. By default, curves are plotted for the viscosity as a function of alpha for fixed temperatures. In this example, a temperature range of 300 to 350°K was chosen. The maximum allowable value of alpha is 0.4 (the viscosity tends to infinity at 0.4), that’s why the alpha max value was set to 0.35. TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 284 PAM-RTM 2014 © 2014 ESI Group Right-click in the Curve Plotter window to open the Plot Settings dialog box. The range parameters are found in the Plot Range tab. In this context (viscosity as a function of temperature and alpha), X means temperature, Y means alpha. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 285 USER’S GUIDE & TUTORIALS (released: Apr-14) Choose alpha in the Plot Variable drop-down list [1] and set Ymax at 0.35 to avoid undefined viscosity function when alpha = 0.4 [2]. In the Resin Properties, select the Thermal tab to enter the thermal conductivity and the specific heat. - Thermal conductivity = 0.11 W/m.K - Specific heat = 1205 J/Kg.K TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 286 PAM-RTM 2014 © 2014 ESI Group In the Resin Properties dialog box, select the Chemical tab and enter the kinetic parameters. Set the Reaction Enthalpy at 3.105 J/kg. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 287 USER’S GUIDE & TUTORIALS (released: Apr-14) Type 1 in the Nb Sub-reactions text field, then click the Set button [1]. This creates one sub-reaction. Then select sub-reaction 1 and push the … button [2] to choose the resin kinetics model. In the Function Editor, select Kinetic_01 for the following resin kinetics model: f ( x, y ) = A × y m × (1 − y ) p × e −E x A = 9170000 E = 7220 m = 0.8 p = 0.2 After defining the chemical reaction, it is possible to view the conversion curves in time for different temperatures. Push the View button in the Chemical tab of the Resin Editor TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 288 PAM-RTM 2014 © 2014 ESI Group to open the Kinetics Viewer dialog. Set the appropriate temperature and time range, then push the Plot button. This viewer is useful to know quickly how the resin behaves at different temperatures. For example, since we know that the viscosity becomes very large when alpha is near 0.4, we should try to avoid alpha values larger than, say, 0.1 with a good safety margin. This means that the part must be filled in about 250 s. if the temperature is 350 K. Now set the properties of the reinforcement as follows : - Density: 2565 kg/m3 - Thermal conductivity: 0.2 W/m.K - Specific heat: 1205 J/Kg.K - Effective conductivity: 0.3 W/m.K - Permeability: K1=K2=K3=1.5 10-10 m² And the parameters of the zone: - Porosity: 0.5 - Thickness: 0.005 m Define the boundary conditions. - Injection pressure (Group 9) = 2.105 Pa. - Vent pressure (Group 10) = 0 Pa. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 289 USER’S GUIDE & TUTORIALS (released: Apr-14) Simulation Cases Case 1 The first case is carried out with the following conditions: - Initial temperature of the mold and fibers: 300 degrees K - Temperature of the injected resin: 300 degrees K - Temperature of the mold walls: 350 degrees K To set the Initial fibers and mold temperature, double-click on Process and select the Thermal tab. The temperature of the resin is specified in the injection port parameters: TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 290 PAM-RTM 2014 © 2014 ESI Group To define the thermal boundary conditions, right-click on Boundary Conditions and click on New->Temperature, then double-click on Temperature_-1 to open the Boundary Condition dialog box. The resin is injected at 300 degrees K in the mold cavity. Since the upper and lower mold walls are heated at 350 degrees K, the resin temperature increases close to the mold walls. This reduces the viscosity of the resin and tends to accelerate the resin flow along the top and bottom walls of the mold as illustrated below. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 291 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 292 PAM-RTM 2014 © 2014 ESI Group Note that the flow front is not only accelerated on the top and bottom mold walls because of a lower resin viscosity, but also in the center as a result of the convergent geometry of the part. When the resin has reached the thinner section on the right, the flow front has become straight. As the temperature in the cavity increases, the resin viscosity decreases, and the curing reaction begins to solidify the resin. The figure below shows the degree of cure at the end of the filling: TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 293 USER’S GUIDE & TUTORIALS (released: Apr-14) Case 2 In this second test, the boundary conditions are slightly different : - Initial temperature of the mold and fibers: 300 degrees K - Temperature of the injected resin: 300 degrees K - Temperature of mold walls : 350 degree K on top and 330 degree K on bottom In this case, the resin viscosity is not uniformly distributed through the thickness because the temperature of the top mold wall is higher than that of the lower wall. Therefore, the resin flow is faster near the upper mold wall at the beginning of the injection. However because of the combined effects of the temperature, degree of cure and convergent geometry, the flow front is almost straight at the end of filling. The degree of cure distribution at the end of the injection is not very interesting. The cycle time will be longer than in the previous case. The degree of cure of the part is also not uniform. So the mechanical properties of the part will vary in each section. This can be disastrous when the part will be used. The figures below show the segmented filling patterns, the temperature field at the end of the injection and the degree of cure at the end of the injection. TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Non-Isothermal Injection 294 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 295 USER’S GUIDE & TUTORIALS (released: Apr-14) Case 3 The temperature boundary conditions of the third case are the following: - Initial temperature of the mold and fibers: 300 degrees K - Temperature of the injected resin: 350 degrees K - Temperature of mold walls: 320 degrees K TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 296 PAM-RTM 2014 © 2014 ESI Group For this case, the temperature of the resin is larger than the temperature of the mold. This has several consequences. First of all, the figures below show that resin is cooled down by the mold when it enters the cavity. At the end of the filling, the temperature is almost uniform in the part. Secondly, the resin front is not distorted and remains nearly straight. Finally, because the temperature of the resin stays much lower, the degree of cure at the end of the injection is very small (0.005). The major problem in this case is that the filling time is very long (about 850 s. compared to 300 s. for the first case), because the viscosity is higher. TUTORIALS Non-Isothermal Injection PAM-RTM 2014 © 2014 ESI Group 297 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Non-Isothermal Injection USER’S GUIDE & TUTORIALS (released: Apr-14) 298 PAM-RTM 2014 © 2014 ESI Group CURING OF A PLATE The files related to this example are: - curing_1d_start.unv (starting mesh) - curing_1d.dtf + curing_1d.unv (solution) Visualization of the Mesh and Groups Begin by creating a new Curing simulation with File->New and import the mesh file curing_1d_start.unv. Visualize the mesh and groups of nodes. You should have the following: This simplified problem should be seen as a cross section in a thick rectangular plate, on which the temperature is fixed on top and bottom and the heat flux is zero all around the part. This leads to a 1D heat transfer problem through the thickness of the part. TUTORIALS Curing of a Plate PAM-RTM 2014 © 2014 ESI Group 299 USER’S GUIDE & TUTORIALS (released: Apr-14) Simulation Parameters Numerical Parameters Use Simulation->Numerical Parameters to open the Curing Numerical Parameters dialog box, select the Time Step tab and set the following parameters: - Max. Experiment Time: 3600 - Max. Number of Steps: 1000 Notes: · For a curing and preheating simulation, the time step is fixed and is calculated as: dt = Max. experiment time/Max. number of steps Resin Parameters Open the Resin Properties dialog box and set the following parameters: - Resin Name: Vinylester - Density: 1083 kg/m3 - Specific Heat: 1205 J/Kg.K - Enthalpy: 266342 J/Kg - Add a new reaction, open the Function Editor and select Kamal-Sourour model (Kinetic_01) with A=9.17E6, E=7289, m=0.85 and p=1.15 Use the View button to verify the chemical model. As illustrated in the figure below, this function allows visualizing resin conversion curves, i.e., the evolution of the degree of polymerization (alpha) in time for different processing temperatures. TUTORIALS Curing of a Plate USER’S GUIDE & TUTORIALS (released: Apr-14) 300 PAM-RTM 2014 © 2014 ESI Group On these curves of isothermal conversion, the value of 1 means that the resin has been cured completely. Curves with a smaller slope are obtained for lower temperatures. Change the processing temperature and the time scale to visualize the effect of temperature on the curing time. Fiber Parameters Enter the following parameters. - Name: Glass - Density: 2565 Kg/m3 - Specific Heat: 1205 J/Kg.K - Effective Conductivity of the saturated reinforcement (for each direction: K1, K2, K3): 0.25 W/m.K Note: · TUTORIALS Curing of a Plate For curing simulations, it is not necessary to specify the conductivity of the dry fibers nor the conductivity of the resin. The single conductivity value that will be used is the effective conductivity, which is the conductivity of the composite. PAM-RTM 2014 © 2014 ESI Group 301 USER’S GUIDE & TUTORIALS (released: Apr-14) Zones Assign the material Glass to the zone 6. Choose a porosity of 0.57, i.e., the fiber volume fraction is 43%. Note: · For a curing simulation, the meaning of porosity is the same as in the simulation of injection. Porosity is equal to 1-Vf, where Vf is the volume fraction of fibers. Boundary Conditions Create a new Temperature boundary conditions. TUTORIALS Curing of a Plate USER’S GUIDE & TUTORIALS (released: Apr-14) 302 PAM-RTM 2014 © 2014 ESI Group Open the Function Editor [1] to define a curve of the temperature vs. time. Choose piecewise_linear and enter the points in the following sequence (the order is very important): · (-10000, 0) · (0, 293) · (600, 333) · (10000, 333) The first point is used to avoid problems in case there would be slightly negative time values generated during the simulation. The last point tells the software to keep the temperature constant to 333 degrees after 600 seconds of curing. Otherwise, the software would extrapolate using the slope defined by the two last points. Repeat this procedure now for the second boundary condition (group 8). TUTORIALS Curing of a Plate PAM-RTM 2014 © 2014 ESI Group 303 USER’S GUIDE & TUTORIALS (released: Apr-14) Sensors In order to get curves of temperature in time, three sensors are set in the cavity. Define the sensors as Points and set the following coordinates: · (0.005, 0.00635, 0.) (lower quarter) · (0.005, 0.0127, 0.) (middle) · (0.005, 0., 0.) (boundary condition) Simulation Results Save the .dtf file and launch the simulation. Select Temperature and Cure scalar fields in the display toolbar. You should have the following. Note on the Cure picture that it begins in the center of the part and ends up on the top and bottom faces. This is important to avoid a build up of residual stresses in the part. The curve viewer can be used to display the following curves. In the explorer, rightclick each sensor and choose Plot. TUTORIALS Curing of a Plate USER’S GUIDE & TUTORIALS (released: Apr-14) 304 PAM-RTM 2014 © 2014 ESI Group Note that sensor values are saved in text files so that you can import them later in more advanced plotting software like Microsoft Excel or GNUPLOT. In this example, a file named curing1d_Temperature_Curing_sensors.dat is generated for temperature values on sensors, and a file named curing1d_Cure_sensors.dat contains the extent of cure values on each sensor. The format of these files is simple. The first column represents time, the next ones contain the scalar field value for each sensor. These files can easily be imported in plotting software. TUTORIALS Curing of a Plate PAM-RTM 2014 © 2014 ESI Group 305 USER’S GUIDE & TUTORIALS (released: Apr-14) CURING OF A PART WITH AN INSERT The files related to this example are: - curing_insert.unv (starting mesh) - curing_insert_1.dtf, curing_insert_2.dtf, curing_insert_3.dtf, (solution) + curing_insert.unv Objectives of the Analysis This example will show you how to: - Perform an analysis of the curing process on a part containing a steel insert, - Use sensors. Visualization of Groups and Zones The part simulated in this example contains a metallic insert, which has an influence on the curing of the composite. The geometry of the complete part is extruded from the section shown below, so a two-dimensional analysis is appropriate here. Create a new Curing simulation with File->New. Import the mesh file curing_insert_start.unv. Visualize the zones and groups of nodes. You should have the following display. Zone number 21 will be used for the metallic insert, and zone 19 for the fiber preform. Group number 22 and 23 are used for temperature boundary conditions. TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Curing of a Part with an Insert 306 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 307 USER’S GUIDE & TUTORIALS (released: Apr-14) Simulation Parameters Set the Max. experiment time to 2000 s. and the Max. number of steps to 500, which leads to a constant time step of 4 s. Open the Resin Properties dialog box. To simulate the resin cure, the following parameters that describe the resin must be specified: - Name: Vinylester - Density: 1083 Kg/m3 - Thermal Conductivity: 0.25 W/(m.K) - Specific Heat: 1205 J/(Kg.K) - Reaction Enthalpy: 300000 J/Kg - Add a new reaction, open the Function Editor and select Kamal-Sourour model (Kinetic_01) with A=9.17E6, E=7289, m=0.85 and p=1.15. Double click now on the reinforcement. In this analysis, it is not necessary to enter the permeability of the reinforcement since there is no flow involved in curing simulation. However, for the thermal analysis, some parameters need to be specified in the Fabric Properties. Enter the following parameters: - Density: 2565 Kg/m3 - Specific Heat: 1205 J/(Kg.K) TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 308 - Thermal Conductivity: 0.25 W/(m.K) - Effective Conductivity: 0.3 W/(m.K) PAM-RTM 2014 © 2014 ESI Group Set isotropic thermal conductivity (K1=K2=K3=0.25W/(m.K)). Use the Direction dropdown list [1] to select the direction to set. For constant conductivity, the value is updated each time a character is typed in the text field (no need to Apply). To specify conductivity as a function of temperature, you would choose f(temperature) in the Model drop-down list, then click the … button to select a function. Finally, the aluminum insert must be created. Create a new Solid material by rightclicking the Materials item in the explorer, then choose New->Solid, as shown in the figure above. Open the Solid Properties dialog box by double-clicking the new solid. Note that there are no specific materials for inserts in PAM-RTM™. The Solid material type must be used when you need to specify a non-permeable material such as metallic or foam inserts. TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 309 USER’S GUIDE & TUTORIALS (released: Apr-14) The following parameters for the aluminum insert must be specified: - Density: 2702 Kg/m3 - Specific Heat: 900 J/(Kg.K) - Thermal Conductivity: 2.165 W/(m.K) Before launching the actual simulation, it is necessary to assign the appropriate material to each zone and to set the boundary conditions. Assign the aluminum insert to zone 21 and the default fabric to zone 19. The porosity of zone 2 (insert) should be set to zero for consistency. However if you forget to do so PAM-RTM™ automatically assigns a zero porosity to solid-type materials. To facilitate the analysis, sensors will now be defined with the Create Sensors dialog box (Simulation->Create Sensors). In the Method drop-down list, choose two points and set the number of sensors to 5. Enter the coordinates of Point 1 (0.09, 0., 0.) and Point 2 (0.09, 0.03, 0.) and click the Create button. TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 310 PAM-RTM 2014 © 2014 ESI Group The initial temperature of the fibers and the mold is 310°K (to be set in the Process Curing dialog box). TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 311 USER’S GUIDE & TUTORIALS (released: Apr-14) Three cases corresponding to three different curing strategies will be analyzed: 1. Mold wall at 340°K. 2. Lower mold wall at 350°K and upper mold wall at 330°K. 3. Mold walls initially at 310°K with a linear temperature variation in time up to 340°K. Curing Simulations Case 1 (mold walls at 340°K) Create the temperature boundary conditions for the group 22 and 23, and set the temperature at 340. Save and launch the simulation. The figure below shows the temperature boundary conditions. Heating is performed from the outside on the top and bottom surfaces of the part. The first parameter to verify in the simulation results is resin conversion. The results below show that curing begins on the sides. Therefore the solidification of the resin begins close to the mold walls, i.e., on the outside of the part. Because of the heat TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 312 PAM-RTM 2014 © 2014 ESI Group generated by the exothermic chemical reaction, the solidification moves then towards the center of the part. Resin conversion reaches then its peak at the center of the part. Note that the metallic insert remains at a nearly constant temperature of 320°K. This means that its temperature is lower than the extremities of the mold. So the curing rate of the resin is minimal near the insert. This type of curing from outside to inside will have several effects on the part. First of all, as the solidification of the resin begins on the outside of the part, this means that shrinkage will occur first on the outside. This is usually one cause of poor surface finish. Obviously, this approach cannot be used if a class A surface is required. Another problem is related to the thermal residual stresses, which result from a delayed cure in the center of the part while the outside has already become rigid. This can affect considerably the mechanical properties of the part. Finally, the slow cure rate near the insert can cause a problem, if the resin is not sufficiently cured. The region located near the insert will have a weaker mechanical resistance. As the insert is usually connected to another part, it will be submitted to significant loadings that might create delaminations in the composite. The figures below show the evolution of cure in time in the part. The evolution of this parameter is closely connected to temperature. Indeed, the heat generated by the exothermic chemical reaction will cause a temperature increase. On the other side, the numerical results show that the chemical reaction is accelerated when the temperature reaches its peak. Note the temperature peaks at the center of the part. This is also where most of the heat is liberated by the exothermic chemical reaction. Temperature is smaller near the insert, which acts as a heat sink. This causes a slower cure of the resin in this region and may reduce locally the mechanical properties of the composite. TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 313 USER’S GUIDE & TUTORIALS (released: Apr-14) The exothermic reaction caused the part's temperature to increase significantly. The temperature peaked in the center of the part at about 405°K. This curing strategy from outside to inside is certainly not the best one. As a matter of fact, a series of problems is associated with this approach: - Shrinkage and surface finish - Thermal residual stress - High temperatures in the center of the part TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) - 314 PAM-RTM 2014 © 2014 ESI Group Weak curing rate near the insert The analysis of the sensor recordings leads to the same conclusion. Sensor 1 is positioned on the bottom surface of the mold (y = 0 cm). Then, starting from the lower surface, sensor 2 is located at a quarter position into the part, sensor 3 halfway and sensor 4 three quarters into the part. The extent of cure curves recorded by the sensors show that the center of the part reaches a critical degree of cure (0.7) faster than the outside region. This can lead to problems in the final part. Case 2 (bottom mold wall at 350°K and top wall at 335°K) This curing strategy heats up the composite from one side. Simulation results show that the solidification of the resin begins on the lower surface of the part. Then a curing front progresses through the part, beginning from the highest temperature at the bottom of the part up to the upper surface where the temperature is the smallest. TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 315 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Curing of a Part with an Insert 316 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 317 USER’S GUIDE & TUTORIALS (released: Apr-14) This type of curing has several effects on the quality of the final part. First of all, as the resin at the bottom solidifies and the curing front moves toward the top surface of the part, problems related to shrinkage are no longer present. Therefore the surface finish will be good on the lower surface. If the objective is to obtain a class A finish on one side, only this method will lead to acceptable results. Indeed, although the lower surface TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 318 PAM-RTM 2014 © 2014 ESI Group will have an improved finish, the upper face will show some imperfections. Because the resin is solidifying uniformly from the bottom towards the unconstrained top of the part, there will not be any thermal residual stresses in the composite. The temperature increases with time as the curing front advances until it reaches three quarters of the part. The exothermic chemical reaction of the resin increases significantly the temperature of the part. The maximum temperature reached at three quarters through the thickness is 405°K. Such a high temperature can spoil the resin and decrease its mechanical properties. This type of curing produces better results than the first strategy from outside to inside. In particular, it leads to a better surface finish. However, it is necessary to pay attention to the high temperatures that can be reached. Because of the heat generated during resin cure especially in thick composite parts, it can cause the resin to degrade. The analysis of the sensor curves confirms these results. Indeed, according to the position of the sensors, resin cure does not begin at the same moment and as the temperature increases, the chemical reaction becomes faster. Case 3 (linear heating from 310°K to 330°K) For this simulation the Max. experiment time is set to 3000 s. and the Max. number of steps is left to 500. Create a temperature boundary condition, then specify temperature as a Piecewise_Linear function as shown in the Function Editor dialog below. TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 319 USER’S GUIDE & TUTORIALS (released: Apr-14) Use the Copy command available when you right-click on a boundary condition to avoid entering the control points of the piecewise linear curve twice. TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 320 PAM-RTM 2014 © 2014 ESI Group The figures below show the resin conversion at 1866 s, 2166 s and 1926 s. With this type of heating, curing slowly begins on the sides of the part, then the center catches up and the exothermic reaction begins to solidify the center and then moves towards the sides. TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 321 USER’S GUIDE & TUTORIALS (released: Apr-14) This method presents several advantages. There is no thermal residual stress in the part if the lower and upper surfaces of the part remain unconstrained. The shrinkage of the resin due to curing will not create problems in the part and conditions are met to obtain a good surface finish. The temperatures analysis demonstrates that the temperature peaks at the center of the part are about 20°K lower than the two other cases. This reduces the possibility of spoiling the resin because of overheating. TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 322 PAM-RTM 2014 © 2014 ESI Group However, there is one major drawback with this method of curing a thick composite part: curing cycles take a much longer time to be completed. The results of the sensors next page show that the temperature peak is reached at the center of the part. TUTORIALS Curing of a Part with an Insert PAM-RTM 2014 © 2014 ESI Group 323 USER’S GUIDE & TUTORIALS (released: Apr-14) Conclusion The three curing examples analyzed here highlight the importance of selecting the best curing strategy. Indeed, it all depends on the objective (good surface finish on one or both surfaces). The numerical simulation can help to understand and predict the curing behavior and hence, avoid numerous and costly trial and errors testing. TUTORIALS Curing of a Part with an Insert USER’S GUIDE & TUTORIALS (released: Apr-14) 324 PAM-RTM 2014 © 2014 ESI Group THERMAL CONTACT RESISTANCE The following files will be used: - contact_start.unv (starting mesh) - contact.dtf + contact.unv (solution) Objectives This tutorial shows how to specify parameters for a preheating simulation, taking into account a thermal contact resistance. Previously quads and bricks were allowed for preheating and curing simulations with the old solver, but this is no more the case with the parallel solver, which only supports triangles and tetrahedra. Creation of Groups Use File->New to create a new preheating simulation, and then import the mesh file contact_start.unv. The different zones represent a fiber preform (zone 1) in a mold (zone 2 and 3). First create a group of nodes at the bottom of the mold, then another group on top of the mold. These will be used for imposed temperature boundary conditions. TUTORIALS Thermal Contact Resistance PAM-RTM 2014 © 2014 ESI Group 325 USER’S GUIDE & TUTORIALS (released: Apr-14) do not select A contact interface will then be created at the interface of the bottom and top mold. First select nodes as shown above. Notice that the node common to the top mold, bottom mold, and preform (shown with an arrow in the figure above) was not selected. This is necessary otherwise a free edge would be generated on the mold/preform interface, which would be in conflict with the automatic mold/preform interface. Select nodes the same way on the right side of the part (add the nodes to the same selection). In this example a single group is created containing nodes on both sides of the part, but of course it would be possible to create two groups. Notes: · The contact interface can only be created at the interface between two zones. · If we were working on a 3D mesh, we would select element faces instead of nodes. Once the selection is done, choose Groups->Contact Interface. The creation of a contact interface modifies the mesh. Coincident nodes are created on the interface and elements are disconnected. Choose View->Outline->Free Edges to verify the interface. The red line in the next figure shows that the elements have been correctly disconnected. TUTORIALS Thermal Contact Resistance USER’S GUIDE & TUTORIALS (released: Apr-14) 326 PAM-RTM 2014 © 2014 ESI Group The three groups are shown below. Simulation With the parallel solver, a thermal contact interface is automatically generated between the mold and the preform. The conductance value (reciprocal of the resistance) used on that automatic interface is found by pushing the Parallel Solver Specific Params button in the Advanced Numerical Parameters. For this example we will keep the default conductance of 100 W/m2.K. TUTORIALS Thermal Contact Resistance PAM-RTM 2014 © 2014 ESI Group 327 USER’S GUIDE & TUTORIALS (released: Apr-14) Also in the Advanced tab, select use parallel solver. In the Time Step tab, set max experiment time = 1800 s and max number of steps = 50. In the Process parameters, check that the initial temperature of the fibers and the mold is 300 K. Materials For the fabric: - Density = 2565 Kg/m³ - Thermal conductivity k1 = k2 = k3 = 0.5 W/m.K - Specific Heat = 1205 J/Kg.K For the mold (create a new material of type solid): - Density = 2707 Kg/m³ - Thermal conductivity = 150 W/m.K - Specific Heat = 900 J/Kg.K Zones Associate zone 1 with the Default Fabric and zones 2 and 3 with the Default Mold. Porosity of zone 1 is kept to 0.5, while the porosity of zones 2 and 3 doesn’t really matter as it will be forced to zero by the solver. However it is a good habit to set it to zero. Boundary Conditions Create two temperature boundary conditions. The first is associated with lower mold wall at 310 K and the second with the upper mold wall at 350 K. Create a new contact resistance boundary condition associated with group 3, and set the value of the thermal contact resistance to 0.001 m²K/W. A second simulation will be run with a contact resistance value of 0.01 m²K/W, and a third one with 0.1 m²K/W. TUTORIALS Thermal Contact Resistance USER’S GUIDE & TUTORIALS (released: Apr-14) 328 PAM-RTM 2014 © 2014 ESI Group Sensors Create the following sensors: - A (0.04, 0.49, 0) - B (0.04, 0.51, 0) B A Post-Processing the Results The temperature contour obtained after 1800 sec. is shown below for the third case corresponding to a contact resistance of 0.1 m²K/W. TUTORIALS Thermal Contact Resistance PAM-RTM 2014 © 2014 ESI Group 329 USER’S GUIDE & TUTORIALS (released: Apr-14) By using sensors A, B near the interface between the two parts of the mold, we can observe the influence of the thermal contact resistance. Temperature curves for cases 1, 2 and 3, corresponding respectively to a contact resistance of 0.001, 0.01 and 0.1 m²K/W are plotted below. For case 3 we can see that there is a non-negligible difference of about 7 degrees on both sides of the interface after 1800 sec. TUTORIALS Thermal Contact Resistance USER’S GUIDE & TUTORIALS (released: Apr-14) 330 PAM-RTM 2014 © 2014 ESI Group NON-ISOTHERMAL 3D – FIBERS ORIENTATION This case is a chaining analysis (preheating, heated RTM and curing) for a 3D part with orientations. The following files will be used: - Insert_3D.unv (starting mesh) - Insert_3D_Preheating.dtf + Insert_3D_Preheating.unv (solution) Insert_3D_Heatedfilling.dtf + Insert_3D_Heatedfilling.unv (solution) Insert_3D_Curing.dtf + Insert_3D_Curing.unv (solution) Objective of the Analysis This tutorial will show you how to simulate a chained RTM process stage by stage (preheating -> heated filling -> curing). Data transfer between each stage is explained, for instance how to use the temperature distribution at the end of the preheating analysis to initialize the temperature for filling. Material characteristics and some set-up steps like orientation, and material assignment are common to each step and are described prior to the description of each step. Geometry Description The geometry (Insert_3D.unv) is composed of several 3d parts that have been defined in order to split the insert, the preform and the mold volume which do not have the same physical properties. Part geometry TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 331 USER’S GUIDE & TUTORIALS (released: Apr-14) Zones of the Part The zone IDs corresponding to each material are shown below: Insert: zone ID 1 Mold: zone ID 2 Reinforcement: zone IDs 3 to7 Zones TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 332 PAM-RTM 2014 © 2014 ESI Group Fiber Orientations The orientation of the preform (Zone IDs 3 to7) must be defined as shown below; K1 is parallel to Y and K2 to Z for zones 3,6 and 7; K1 is parallel to Z and K2 to Y for zones 4 and 5. K1 K2 TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 333 USER’S GUIDE & TUTORIALS (released: Apr-14) Material parameters The resin parameters To simulate the resin cure, the following parameters must be specified. In the general tab: - Density: - Viscosity: cure. 1120 Kg/m3 a viscosity function relates viscosity with temperature and the degree of Resin general sub-section dialog box TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) - 334 PAM-RTM 2014 © 2014 ESI Group Select the Viscosity_01 model where A = 5.7E-22, B = 1.45E+4 and C = 15. Viscosity function edition TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 335 USER’S GUIDE & TUTORIALS (released: Apr-14) In the Thermal sub section: - thermal conductivity: 0.13 W/m.K - Specific heat: 1400 J/Kg.K Resin thermal sub section dialog box TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 336 PAM-RTM 2014 © 2014 ESI Group In the Chemical sub section, - Enthalpy: 230000 J/kg Resin chemical sub section dialog box - kinetics model: Kinetic_01 where A=300, B=3277, m=0, p=2, as shown below Kinetic function edition TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 337 USER’S GUIDE & TUTORIALS (released: Apr-14) The fibers parameters The reinforcement characteristics are set as below: - Name: Preform - Density: 2540 kg/m3 - Permeability K1: 6E-11 m2 - Permeability K2=K3: 1E-11 m2 - Thermal Conductivity K1=K2=K3: 0.1 W/m.K - Effective Conductivity K1=K2=K3: 0.3 W/m.K - Specific heat: 840 J/Kg.K The mold parameters The mold characteristics are set as below: - Name: Metal - Density: 2700 kg/m3 - Thermal Conductivity: 10 W/m.K - Specific heat: 950 J/Kg.K Material Assignment For each of the set-up step, the material assignment will be the same. It will have to be done for each step. Visualize the zones of the parts and make material assignment as follows, · zone ID 1 (Insert): Metal · zone ID 2 (Mold): Metal · zone IDs 3 to 7 (Reinforcement): Preform. Keep parameters of all the zones as default: · Porosity: 0.5 · Thickness: 0.0005m Note: · A solid material such as the metal just defined is a non porous material; the porosity here is therefore set to zero. But this is not mandatory, as PAM-RTM will force porosity to zero for solid materials TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 338 PAM-RTM 2014 © 2014 ESI Group Simulation Stage1: Preheating Create a Preheating analysis and import insert_3D.unv, then define fiber orientations, material properties and material assignment to zones as in previous description. The objective of this stage is to simulate 1 hour of part heating before injection starts. Material Database To reuse the defined materials conveniently in the following analysis (heated RTM and curing), it is recommended to add them into the Material Database. For example, right click on Preform in the Model Explorer and select Add to User Database, as shown below. After adding the three materials, the user can check the modified material database by selecting the Simulation -> Manage User Database menu, as shown below Material database content TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 339 USER’S GUIDE & TUTORIALS (released: Apr-14) Note: · The user needs to check if database path is set properly. · In the Menu, select View Options..., then in the Options interface, click on open button (as shown below) to select the file used for material database Material database path setting · If the material database is used for the first time in PAM-RTM, the user should create an empty .dtf file such as my_material_data.dtf in advance with a text editor, then select it in the Options>Paths tab After this operation, the path of this dtf file is stored in the application settings, so it only needs to be entered once. Numerical Settings and DMP solver activation Set the following parameters in Preheating Numerical Parameters interface: · Save temperature: checked · Results sampling period: 50 · Max experiment time: 3600 s · Max number of steps: 250 · Check use parallel solver, as shown below. TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 340 PAM-RTM 2014 © 2014 ESI Group Boundary Conditions and Initial Values - In the Process interface, keep initial temperatures as default, · initial fibers temperature: 300 K · Initial mold temperature: 300 K Create a group which corresponds to a convection boundary condition by selecting faces all around the mold, as shown below. TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 341 USER’S GUIDE & TUTORIALS (released: Apr-14) Group for preheating stage - About the parameters of convection · Reference temperature: 323 K · Convection Coefficient: 300 W/m2.K Job Launching When a job using the parallel solver is launched, a Prompt interface appears automatically to let the user enter the number of processors that will be used, as shown below. TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 342 PAM-RTM 2014 © 2014 ESI Group Parallel job launching Simulation Stage2: Heated RTM Create a Heated RTM analysis and import Insert_3D_Preheating.unv which is the mesh file generated by Preheating analysis and not the initial one Insert_3D.unv. As Insert_3D_Preheating.unv has included the fiber orientation definition in the previous Preheating analysis, there is no need to do it again in this analysis. Check the parallel solver option in the numerical interface Getting defined materials In the Explorer, right click on the Materials folder and select Get from User Database…, then select all the 3 materials and click on OK button to load them into the current model, as shown below, TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 343 USER’S GUIDE & TUTORIALS (released: Apr-14) Material assignment Visualize the zones of the parts and make material assignment as follows, · zone ID 1 (Insert): Metal · zone ID 2 (Mold): Metal · zone IDs 3 to 7 (Reinforcement): Preform Linking Preheating temperature · Double click on Process in the Explorer, and then select the Thermal tab. · Check the Use temperature file box. · Click on the button Open to select the temperature results file. · In this case, the temperature results of previous preheating analysis, Insert_3D_Preheatingt.unf is selected, as shown below, TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 344 PAM-RTM 2014 © 2014 ESI Group End of preheating temperature file path definition Note: · This linking is to import previous Preheating results as initial temperature of the current Heated RTM analysis · The file to select depends on the solver used for computation: - for parallel solver (this case), the file is *t.unf - for old solver, the file is *_p.dof. Boundary Conditions - convection boundary (same as Preheating case, i.e. defined on group 1) - flow rate (group 2, see image below) : · flow_rate = 1E-6 m3/s · resin temperature = 300 K TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 345 USER’S GUIDE & TUTORIALS (released: Apr-14) Groups for filling stage Simulation Stage 3: Curing Create a Curing analysis and import Insert_3D_Preheating.unv. Get the 3 materials from the Material Database and make material assignment to zones. Numerical Settings and DMP solver activation Set the following parameters in Curing Numerical Parameters interface: - Save temperature: checked - Results sampling period: 50 - Max experiment time: 3600 s - Max number of steps: 250 - Check use parallel solver TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 346 PAM-RTM 2014 © 2014 ESI Group Linking Heated filling temperature and Cure - Double click on Process in the Explorer; make sure Resin material is selected - check the boxes of Use temperature file and select Insert_3D_Heatedfillingt.unf - check the boxes of Use degree of cure file and select Insert_3D_Heatedfillingcr.usf End of filling temperature and cure files path definition Note: · Linking files with respect to solver used for curing analysis Temperature file Parallel(DMP) *t.unf old solver Cure degree file *cr.usf *_Thermal_f.dof *_Curing_f.dof Boundary Conditions Convection boundary condition (same as Preheating case) TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 347 USER’S GUIDE & TUTORIALS (released: Apr-14) Analysis of the Results Preheating stage The last time state of preheating is 3655s (stop time was set to 3600s but with the parallel solver the actual last state depends on the sampling period). Because of temperature file linking, the temperature contour of last state is consistent with that of initial state of Heated RTM stage, as shown below. Last state of preheating stage TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 348 PAM-RTM 2014 © 2014 ESI Group Initial state of heated RTM stage (Range Type set as “Auto Step” for an easier comparison) Heated RTM Stage It shows that the filling time is 64.7s and at the end of filling there is a temperature and cure gradient, as shown below, TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 349 USER’S GUIDE & TUTORIALS (released: Apr-14) Temperature and cure distribution (end of Heated RTM) TUTORIALS Non-Isothermal 3D – Fibers Orientation USER’S GUIDE & TUTORIALS (released: Apr-14) 350 PAM-RTM 2014 © 2014 ESI Group Curing Stage Because of temperature and cure files linking, the temperature and cure distribution at curing start (as shown below) are consistent with end of Heated RTM. Temperature and cure distribution(Curing start) After 487 seconds, 100% of the part has reached a resin cure of 90%. The temperature distribution for this time step shows a peak of temperature at the center of the preform. Temperature and cure distribution (end of Curing) Conclusion This tutorial has shown how to perform chained preheating, heated RTM and curing simulations. TUTORIALS Non-Isothermal 3D – Fibers Orientation PAM-RTM 2014 © 2014 ESI Group 351 USER’S GUIDE & TUTORIALS (released: Apr-14) USER DEFINED FUNCTIONS The following files are used in this example. - func_resinviscosity.c (source code template for resin viscosity) - func_resinkinetics.c (source code template for resin kinetics) - func_resinspecheat.c (source code template for resin specific heat) - func_effthermalcond.c (source code template for effective conductivity of a wet reinforcement) Objectives Explain the procedure to compile user defined functions for resin viscosity, kinetics, specific heat, and effective conductivity of a wet reinforcement. This procedure only applies to the parallel solver. Windows Procedure Two batch files and four C-language files (.c) are provided in the installation directory of the PAM-RTM parallel solver, which is in general C:\Program Files (x86)\ESI Group\PAM-RTM\version\Windows-x64\DMP: - compile_rtm_udf_vs.bat (compile script for Visual Studio) - compile_rtm_udf_sdk.bat (compile script for Windows SDK) - func_resinviscosity.c (source code template for resin viscosity) - func_resinkinetics.c (source code template for resin kinetics) - func_resinspecheat.c (source code template for resin specific heat) - func_effthermalcond.c (source code template for effective conductivity of a wet reinforcement) The first batch file is to be used with Visual Studio (free of professional edition), the second one is to be used with the Windows SDK (software development kit). In general it is better to work with Visual Studio, except for the case where the user doesn’t have a professional edition and needs to compile for Windows 64-bit. The free editions of Visual Studio don’t support 64-bit compilation. The free editions of Visual Studio and the Windows SDK can be downloaded from Microsoft’s web site. Here we will focus on user functions for resin viscosity and kinetics. User functions for resin specific heat and effective conductivity are most of the time used to define them as functions of temperature and degree of cure, so it is an advanced application. These will be discussed in the last section of this tutorial. TUTORIALS User Defined Functions USER’S GUIDE & TUTORIALS (released: Apr-14) 352 PAM-RTM 2014 © 2014 ESI Group The first step is to copy the four provided .c files and the appropriate batch file (VS or SDK) in some user directory. It is necessary to copy all the .c files even if only two of them will be edited here (func_resinviscosity.c and func_resinkinetics.c), otherwise the build procedure will fail. Open the batch file in a text editor and check that the PAMRTM_INSTALL_DIR variable corresponds to your actual installation directory, otherwise correct it. Then open the .c files in Visual Studio or any text editor. Note that you don’t have to create a project in Visual Studio. The procedure only relies on command-line tools. In this example we want to define viscosity and kinetics for two resins: my_resin_1 and my_resin_2. The first resin has a viscosity function of material age (i.e. function of time since a resin particle entered the mold): f (t ) = 0.01 + t2 Pa.s 7.2 × 10 5 The second resin has a viscosity function of temperature and degree of cure: f (T , α ) = 2.38 × 10 − 21 ⋅e 14500 + 3.8⋅α T Pa.s Starting from the provided template for the viscosity function, the code to be written by the user is highlighted below. The first resin is using only parameter local_time, which corresponds to the time since a resin particle entered the mold, while the second resin uses parameters temperature and alpha. /* * Return resin viscosity as a function of the current temperature, current degree of cure, or current time. */ real func_resinviscosity( char prefix[], /* case name */ char resin_name[], real temperature, /* current temperature in Kelvin */ real alpha, /* current degree of cure (value between 0 and 1) */ /* case name */ real local_time, mold) */ /* current local time (time since particle entry in the real global_time) injection) */ /* current global time (time since beginning of { TUTORIALS User Defined Functions PAM-RTM 2014 © 2014 ESI Group 353 USER’S GUIDE & TUTORIALS (released: Apr-14) /* ------------- Do not change anything above this line ------------- * * ------------- Program your function below this line ------------- */ if ( strcmp( resin_name, "my_resin_1" ) == 0 ) { return 0.01 + ( local_time * local_time ) / 7.2E5; } else if ( strcmp( resin_name, "my_resin_2" ) == 0 ) { return 2.38E-21 * exp( 14500. / temperature + 3.8 * alpha); } else { printf("unknown resin in user defined viscosity\n"); exit(1); } } Note that this architecture doesn’t currently support units. The solver assumes the returned value is in Pa.s for viscosity, s-1for kinetics. The code to be written for kinetics in file func_resinkinetics.c would have the same structure and is left as an exercise. Note that it is not mandatory to edit both viscosity and kinetics functions. Depending on the user’s needs, only one of viscosity or kinetics could be defined. Even though both functions will be compiled (one of the definitions being the default implementation that just prints an error message and exits), there shouldn’t be issues as long as the user doesn’t choose function type user_dll in the PAM-RTM GUI for a function that is not defined. We recommend that you print some messages in your functions to make sure the code is correctly called. This should only be done for the first run, as it will slow down execution a lot. For instance you could add these lines in func_resinviscosity.c: real visc = … printf("visc = %12.5E, T = %12.5E, alpha = %12.5E\n", visc, temperature, alpha); Now that the code is written, it is time to compile it. The procedure is a bit different for Visual Studio and Windows SDK. TUTORIALS User Defined Functions USER’S GUIDE & TUTORIALS (released: Apr-14) 354 PAM-RTM 2014 © 2014 ESI Group Visual Studio 32-bit target Open a command window with Start>Programs>Microsoft Visual Studio 2005>Visual Studio Tools>Visual Studio 2005 Command Prompt. This is the path for Visual Studio 2005, but it should be almost the same for other versions. This will open a console window in which the environment variables needed to compile with the command line tools are already set (PATH for instance). Then simply type the command: compile_rtm_udf_vs.bat x86 Note the x86 at the end of the command line. This command compiles func_resinviscosity.c, func_resinkinetics.c, func_resinspecheat.c, func_effthermalcond.c, which generates the corresponding four .obj files. If compilation is successful, the command then copies a set of .obj files from the PAM-RTM installation directory to the current directory and links all these .obj files together to generate a dynamic link library called libprocast_DMP.dll. Once the command is done, the user should check the date of libprocast_DMP.dll to make sure it was just generated. If everything looks good, the new libprocast_DMP.dll must then be copied to the installation directory of PAM-RTM and overwrite the file with same name (make a copy of the file before overwriting it). That directory is in general C:\Program Files (x86)\ESI Group\PAM-RTM\CurrentVersion\Windows-x86\DMP. Visual Studio 64-bit target There are only 2 differences for a 64-bit target, compared to the procedure for a 32-bit target. First the console window is opened with a shortcut that contains x64 in its name. For instance with Visual Studio 2005, the shortcut is Start>Programs>Microsoft Visual Studio 2005>Visual Studio Tools>Visual Studio 2005 x64 Win64 Command Prompt. Then the x86 flag at the end of the command must be replaced by x64: compile_rtm_udf_vs.bat x64 The newly generated libprocast_DMP.dll must then be copied to the installation directory of PAM-RTM and overwrite the file with same name. That directory is in general C:\Program Files (x86)\ESI Group\PAM-RTM\CurrentVersion\Windowsx64\DMP. Be careful not to copy a 64-bit DLL in a 32-bit directory, or vice-versa. TUTORIALS User Defined Functions PAM-RTM 2014 © 2014 ESI Group 355 USER’S GUIDE & TUTORIALS (released: Apr-14) Windows SDK 64-bit target Referring again to the procedure for Visual Studio 32-bit, the main difference here is that we use the following shortcut to open the console window, or a similar shortcut for a different version of the SDK: Start>Programs>Microsoft Windows SDK v7.1>Windows SDK 7.1 Command Prompt You should see a message similar to Targeting Windows 7 x64 printed in the console. Then the command to compile is: compile_rtm_udf_sdk.bat x64 Once again be careful with the x64 flag at the end of the command line. The batch file won’t run correctly if you forget to specify it. Linux Procedure First locate the directory containing the binaries of the current PAM-RTM version. The command “which pamrtmdmp” should allow you to identify that directory. Let’s call that directory rtm_dir, we will need it again below. There is a subdirectory user_MP in that directory. Copy all the files in rtm_dir/user_MP to the user directory where you will compile. This will copy some object files (.o) as well as the makefile compile_rtm_udf.mk and all the .c source code templates. Edit the appropriate .c files to define viscosity and/or kinetics and/or specific heat and/or effective conductivity, as explained above. Before launching compilation there is a critical step required to set up the appropriate compiler, which is the mpicc of the Platform-MPI version used by PAM-RTM. Be careful that there could be other versions of mpicc installed on your system, and using another version could lead to problems. The mpicc of the Platform-MPI used by PAMRTM is located in rtm_dir/pcmpi/bin. Modify the PATH environment so that this directory is searched first, with a command such as: export PATH=rtm_dir/pcmpi/bin:$PATH Once the PATH is correctly set, launch compilation with: make –f compile_rtm_udf.mk This will generate libprocast_DMP.so. Copy the new .so to overwrite the file with same name in the PAM-RTM installation directory. TUTORIALS User Defined Functions USER’S GUIDE & TUTORIALS (released: Apr-14) 356 PAM-RTM 2014 © 2014 ESI Group Setting the parameters in the PAM-RTM GUI In order to have the user defined viscosity and kinetics functions called for a given model, function type user_dll must be selected in the PAM-RTM GUI. It is important to understand that libprocast_DMP.dll has no other use than to evaluate viscosity and/or kinetics and/or specific heat and/or effective conductivity for the only cases where user_dll is selected in the PAM-RTM GUI. If any type other than user_dll is selected, the DLL won’t be called. This means there will not be any side effects if the user compiled DLL is kept in the PAM-RTM installation directory to run cases not using user functions. TUTORIALS User Defined Functions PAM-RTM 2014 © 2014 ESI Group 357 USER’S GUIDE & TUTORIALS (released: Apr-14) User functions for resin specific heat and effective conductivity These functions are used most of the time to define resin specific heat and effective conductivity of a wet reinforcement as a function of temperature and degree of cure ( f (T , α ) ). Suppose we want to define the specific heat as the following function: c p (T , α ) = 2 ⋅ (T − 273) + 1800 for α ≤ 0.5 c p (T , α ) = 3 ⋅ (T − 273) + 1500 for α > 0.5 This specific heat model is just for the sake of the example, it doesn’t correspond to a real resin. For a resin with name my_resin_1, the corresponding user code would be: /* * Return specific heat of pure resin (i.e. not mixed with fibers). */ real func_resinspecheat( char prefix[], /* case name */ char resin_name[], real temperature, /* current temperature in Kelvin */ real alpha, /* current degree of cure (value between 0 and 1) */ /* resin name */ int* vars) /* return 1 for a function of temperature or 2 for a function of temperature and cure */ { /* ------------- Do not change anything above this line ------------- * * ------------- Program your function below this line ------------- */ /* Return value must be in J/kg/K */ if ( strcmp( resin_name, "my_resin_1" ) == 0 ) { if ( alpha <= 0.5 ) { return 2. * ( temperature - 273. ) + 1800.; } else { return 3. * ( temperature - 273. ) + 1500.; } TUTORIALS User Defined Functions USER’S GUIDE & TUTORIALS (released: Apr-14) *vars = 1; 358 PAM-RTM 2014 © 2014 ESI Group /* function of temperature only */ } else { printf("unknown resin in user defined specific heat\n"); exit(1); } } To have the user function for cp called, the user must select first f(temperature) or f(temperature, alpha) for the cp of the resin in the PÂM-RTM GUI, then user_dll. Note that it is the user’s responsibility in his code to return “*vars = 1” for a function of temperature, or “*vars = 2” for a function of temperature and alpha, since the same user function is used for both situations. When “*vars = 2” is returned, the solver adds an extra term in the energy equation to take into account the time dependency of cp through alpha: For the effective conductivity of a wet reinforcement, since it involves the combination of a resin and a reinforcement, we recommend the following code structure. Here we have resins my_resin_1 and my_resin_2, and reinforcements my_rf_1 and my_rf_2. /* * Return effective thermal conductivity principal values (k1, k2, k3) of the mix of resin and fibers, i.e. the * conductivity to be used in the wet area. */ void func_effthermalcond( char prefix[], char resin_name[], char reinforcement_name[], real vf, TUTORIALS User Defined Functions /* case name */ /* resin name */ /* reinforcement name */ /* fiber volume fraction (value between 0 and 1) */ PAM-RTM 2014 © 2014 ESI Group 359 USER’S GUIDE & TUTORIALS (released: Apr-14) real temperature, /* current temperature in Kelvin */ real alpha, /* current degree of cure (value between 0 and 1) */ real *k1, direction */ /* returned effective conductivity in the first principal real *k2, direction */ /* returned effective conductivity in the second principal real *k3) direction */ /* returned effective conductivity in the third principal { /* ------------- Do not change anything above this line ------------- * * ------------- Program your function below this line ------------- */ /* Returned values must be in W/m/K */ *k1 = 0.; *k2 = 0.; *k3 = 0.; if ( strcmp( resin_name, "my_resin_1" ) == 0) { if (strcmp( reinforcement_name, "my_rf_1" ) == 0) { *k1 = ... *k2 = ... *k3 = ... } else if ( strcmp( reinforcement_name, "my_rf_2" ) == 0) { *k1 = ... *k2 = ... *k3 = ... } else { printf("unknown combination of resin and fibers\n"); exit(1); } } else if ( strcmp( resin_name, "my_resin_2" ) == 0) { if ( strcmp( reinforcement_name, "my_rf_1" ) == 0) { *k1 = ... *k2 = ... *k3 = ... } else if ( strcmp( reinforcement_name, "my_rf_2" ) == 0) { TUTORIALS User Defined Functions USER’S GUIDE & TUTORIALS (released: Apr-14) 360 PAM-RTM 2014 © 2014 ESI Group *k1 = ... *k2 = ... *k3 = ... } else { printf("unknown combination of resin and fibers\n"); exit(1); } } else { printf("unknown resin in user defined effective conductivity\n"); exit(1); } } To have the user function for effective conductivity called, the user must select first f(temperature) or f(temperature, alpha) in the PAM-RTM GUI, then user_dll. Note that the fiber volume fraction of the zone (or local fiber fraction if draping is used) is also passed as parameter to the effective conductivity function. The user could implement a rule of mixture in his function so that the effective conductivity is valid for any fiber fraction. TUTORIALS User Defined Functions PAM-RTM 2014 © 2014 ESI Group 361 USER’S GUIDE & TUTORIALS (released: Apr-14) ONE SHOT FILLING SIMULATION The following files are used in this example. - one_shot_start.unv (starting mesh) - one_shot.dtf + one_shot.unv (solution) Objectives The goal of this tutorial is to show how to use the one shot filling simulation, i.e. a very quick estimation of the filling time and location of the last points filled. This simulation doesn’t solve the intermediate states of the flow. Only a few resolutions of Darcy’s equation are needed, compared to thousands for a standard filling simulation, meaning just a few seconds of CPU time, even on a huge mesh. Material Properties The 2D mesh can be seen as a cross section in a solid part with a T junction (see tutorial “Comparison 2D – 2.5D – 3D”). For this case, material orientations were defined because a reinforcement with non-isotropic permeability is used. The K1 principal permeability directions follow the shape of the part. They were set by projection of the elements on a “curve” (command Mesh>Orientations>Set K from Selected Nodes, see tutorial “Fiber Orientations”). The direction orthogonal to K1 and in the plane of the elements is here the transverse direction K3. Since we cannot set directly K3 in PAMRTMTM, the way to do it is to set K2 out of plane with Mesh>Orientations>Set Vectors and vector (0., 0., 1.). K3 is always calculated by PAM-RTMTM orthogonal to K1 and K2, meaning we will have finally K3 orthogonal to K1 and in the plane of the elements. The K1 and K2 directions are shown below. The central zone has isotropic permeability, so orientations are not specified. TUTORIALS One Shot Filling Simulation USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS One Shot Filling Simulation 362 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 363 USER’S GUIDE & TUTORIALS (released: Apr-14) The material properties are summarized below. TUTORIALS One Shot Filling Simulation USER’S GUIDE & TUTORIALS (released: Apr-14) 364 PAM-RTM 2014 © 2014 ESI Group Boundary Conditions Three groups of nodes are created on the extremities of the part, that will be used as injection lines. All the lines are active at the same time, and all use imposed pressure. However the center injection line has a lower pressure (1 bar) while the left and right lines have 2 bars pressure. No vent is specified, as the goal of the one shot simulation is to help locate vents. The groups are shown below, with the corresponding boundary conditions in the document’s tree. group 38 group 37 TUTORIALS One Shot Filling Simulation group 39 PAM-RTM 2014 © 2014 ESI Group 365 USER’S GUIDE & TUTORIALS (released: Apr-14) One Shot Parameters Only one parameter needs to be changed in order to run a one shot simulation, when compared to a standard filling simulation. It is the do one shot parameter, found in the OneShot tab of the Numerical Parameters. This parameter must be checked to run a one shot simulation. TUTORIALS One Shot Filling Simulation USER’S GUIDE & TUTORIALS (released: Apr-14) 366 PAM-RTM 2014 © 2014 ESI Group Launching the Simulation and Post-processing Save the document and launch the simulation. When it is done, push the Reload Results button in the Results toolbar. A folder Last Points Filled is added to the document’s tree. It contains the list of the last points filled, with the fill time for each point. Clicking one of these points in the document’s tree highlights the corresponding point in the 3D view. Most of the time, the output of a one shot simulation won’t be a single point, but a set of points, which is some kind of fuzzy region for the actual last point filled. All these points should be considered candidates for potential last point filled. They are all within a 0.1 % tolerance on the total fill time. This is an internal tolerance that cannot be modified by the user in the current version. TUTORIALS One Shot Filling Simulation PAM-RTM 2014 © 2014 ESI Group 367 USER’S GUIDE & TUTORIALS (released: Apr-14) Running first a one shot simulation, then unchecking the do one shot parameter to run a standard filling simulation, it is possible to superimpose the last points filled with the filling times contour, to check if they match. Here the match is very clear. TUTORIALS One Shot Filling Simulation USER’S GUIDE & TUTORIALS (released: Apr-14) 368 PAM-RTM 2014 © 2014 ESI Group GENPORTS The following files are used in this example. - genports_start.unv (starting mesh) - genports.dtf + genports.unv (solution). Objectives The goal of this tutorial is to show how to use the GenPorts module. GenPorts uses a genetic algorithm to find the optimal configuration of injection ports that minimize fill time. In this tutorial, we want to find the best configuration for 3 inlets on a complex part (shown below). Material Properties and Boundary Conditions Most of the material properties and boundary conditions usually set up in a standard RTM simulation are ignored by GenPorts. Actually the only material properties that are taken into account are permeability (principal directions and orientations) and porosity. High permeability areas used to define runners or race tracking are thus supported by GenPorts. For the boundary conditions, the simulation will run without any boundary condition defined, as GenPorts will create internally the needed injection points and ignore any TUTORIALS GenPorts PAM-RTM 2014 © 2014 ESI Group 369 USER’S GUIDE & TUTORIALS (released: Apr-14) boundary condition defined by the user. The optimization is independent of the actual pressure value used. It is assumed that all the points use the same pressure. For this example, isotropic permeability is used (k1 = k2 = k3 = 2e-10 m2) with a porosity of 60%. GenPorts Parameters The GenPorts parameters are located in the GenPorts tab of the RTM Numerical Parameters. Assuming the user has already set up a model for a standard RTM simulation, there are basically 2 parameters that need to be changed to run a GenPorts simulation: the optimize inlets locations parameter must be checked, and the number of inlets to be used (nb inlets) has to be set. The other parameters, which are related to the genetic algorithm engine, could keep their default values. However here to reduce the CPU time, we use a smaller population of 100 and reduce the total number of generations to 500. The parameters are shown below. It is very important to understand the meaning of population. A population is made of individuals. Here an individual is actually an injection configuration, i.e. in this example a set of 3 points (nb inlets). In the figure below we show 3 individuals (red set, green set and blue set). In this example a population of 100 individuals is used. We consider that value enough to insure a good “covering” of the part, taking into account the fact that the initial population is generated completely randomly, meaning that some individuals will be very “weak” (i.e. lead to a longer fill time, such as the green one below). For a larger part, the population should be increased. TUTORIALS GenPorts USER’S GUIDE & TUTORIALS (released: Apr-14) 370 PAM-RTM 2014 © 2014 ESI Group The idea behind optimization using genetic algorithms is that the individuals within the population will combine to give birth to children. Some of the characteristics of both parents will be kept in the generation of a child, and some characteristics will be completely random. For instance, a point could be randomly generated on the line connecting 2 points from both parents. In that case, the characteristic is not completely random, it still is related to the characteristics of both parents even though some randomness is introduced. That is called a crossover. Also sometimes a mutation can occur. This is a more dramatic change in the characteristics of a child. For instance, a completely random node could be chosen on the mesh instead of being generated from the parents. The probability of a mutation can be entered with the prob mutation parameter. The user doesn’t have control on the crossover parameters in the current version. The number of individuals in a population is specified by the population parameter. That is an approximate number; the population will vary slightly from generation to generation as some individuals will die in the process. The maximum number of generations that will be calculated is specified in nb generations. It is possible that the calculation will stop earlier, if the calculation engine doesn’t detect any significant improvement in the results for steady gen generations, meaning that a steady state has been reached. TUTORIALS GenPorts PAM-RTM 2014 © 2014 ESI Group 371 USER’S GUIDE & TUTORIALS (released: Apr-14) Launching the Simulation and Post-processing The calculation is launched the usual way, by pushing the green arrow button saving the document. , after A typical log file is shown below. The first column is the current generation, the second column shows the cumulative number of evaluations done, the third column shows the cumulative CPU time, and the last 3 columns show the best, average, and standard deviation results for the evaluation of the formulation on the population. Note that these high values come from the evaluation of a “mold coefficient” formulation, in which only material properties are taken into account, not boundary conditions. These values are related in some way to the fill time, but they are not of course actual time values. Once the calculation is done, the user pushes the usual reload results button . This will add a Best inlets locations folder to the model explorer, in which the coordinates of the points are listed. The points are also displayed in the 3D view, as shown below. TUTORIALS GenPorts USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS GenPorts 372 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 373 USER’S GUIDE & TUTORIALS (released: Apr-14) SEQUENTIAL INJECTION (TRIGGER MANAGER) The following files are used in this example. - sequential_start.unv (starting mesh) - sequential.dtf + sequential.unv (solution) Objectives The goal of this tutorial is to show how to use the trigger manager to define a sequential injection. A long part is injected with many injection lines, which will be opened and closed sequentially in time. Even though it was possible with earlier versions to simulate sequential injection by using state curves and running many partial simulations, the trigger manager, introduced in PAM-RTMTM 2009, makes this kind of data setup much easier. Since PAM-RTMTM 2013 the trigger manager is supported by the parallel solver; the tutorial uses the parallel solver. Boundary Conditions inlets outlet Four groups are created, equally spaced along the length of the part. The rightmost group is used for an outlet (vent) boundary condition, while the three other groups are inlets. Initially only the leftmost inlet is active (its state parameter has a value of one, TUTORIALS Sequential Injection (Trigger Manager) USER’S GUIDE & TUTORIALS (released: Apr-14) 374 PAM-RTM 2014 © 2014 ESI Group while the two other inlets have state=0). The outlet is kept open for the whole simulation. The corresponding entities in the document’s tree are shown below. The parallel solver doesn’t support internal injection lines, i.e. defined with nodes that are not on free edges of the part. Therefore it is necessary to add some small surfaces orthogonal to the part, on which injection lines will be defined (see images below). Here the height of these surfaces is 5 millimeters, and 2 rows of elements were used. Note that PAM-RTM doesn’t have a tool to create and mesh these small surfaces, so the user has to create them in his CAD software or mesh generator. TUTORIALS Sequential Injection (Trigger Manager) PAM-RTM 2014 © 2014 ESI Group 375 USER’S GUIDE & TUTORIALS (released: Apr-14) Material definition Because injection will be done in these small surfaces or “channels”, permeability, thickness and porosity of these channels must match the values used for the part. In this example, default fabric permeability of 10-9m2, thickness of 5mm and porosity of 50% are used. TUTORIALS Sequential Injection (Trigger Manager) USER’S GUIDE & TUTORIALS (released: Apr-14) 376 PAM-RTM 2014 © 2014 ESI Group Sensors sensor s1 sensor s2 Two sensors are created just after the second and third injection lines. These sensors will be used as inputs by the trigger manager. For instance, when the resin will touch the first sensor, the first injection line will be closed, and the second one opened. The position of the sensors can be seen on the picture below. Trigger Manager The goal of the trigger manager is to manage input conditions and fire outcomes when these conditions are reached. For instance an input condition could be the resin pressure on a sensor: when a given pressure is reached (parameter threshold of a trigger), a list of events is fired, such as closing a vent or opening an inlet. Other types of inputs are the injected or lost resin volume on a specific inlet or outlet, or the global injected or lost volume on all inlets and outlets. In this tutorial, we will use an input condition based on the filling factor, to determine if the flow has reached a given sensor: we use a threshold with a value of one. Note that another way to detect that the flow has reached a given sensor would be to use a trigger based on pressure, with a very small pressure value. TUTORIALS Sequential Injection (Trigger Manager) PAM-RTM 2014 © 2014 ESI Group 377 USER’S GUIDE & TUTORIALS (released: Apr-14) The first trigger will manage closing of the first inlet and opening of the second inlet. To create the trigger, right-click on the Triggers folder of the document’s tree, and choose New. This opens the trigger dialog box shown below. Enter the parameters as shown. This means that when the flow will reach the first sensor (s1), condition detected by the fact that the filling factor (variable filling) has reached a value of one (threshold) on that sensor, outcomes will be fired. Once a trigger has been defined, outcomes can be created on that trigger by rightclicking the trigger in the document’s tree, and choosing New Outcome. This opens the following dialog box. TUTORIALS Sequential Injection (Trigger Manager) USER’S GUIDE & TUTORIALS (released: Apr-14) 378 PAM-RTM 2014 © 2014 ESI Group First give a meaningful name to the outcome, such as “close line 1”. Then enter the Group ID on which the specified coefficient will be set when the trigger is fired. Here we set the state coefficient of the inlet to zero, meaning the inlet is closed. Define another outcome for the activation of the second inlet, as shown below. Repeat this procedure for the second sensor, so that the second inlet is closed and the third inlet is opened when resin reaches the second sensor. TUTORIALS Sequential Injection (Trigger Manager) PAM-RTM 2014 © 2014 ESI Group 379 USER’S GUIDE & TUTORIALS (released: Apr-14) Launching the Simulation and Post-processing The parallel solver is selected in the Advanced numerical parameters. Save the document and launch the simulation. When it is done, push the Reload Results button in the Results toolbar. Have a look at the filling steps. The total filling time is 353 seconds. TUTORIALS Sequential Injection (Trigger Manager) USER’S GUIDE & TUTORIALS (released: Apr-14) 380 PAM-RTM 2014 © 2014 ESI Group Images below show the pressure field just before and just after the triggers are fired, i.e. when the fill factor reaches a value of one on the sensors. The first trigger is fired around 120 seconds, and the second trigger around 236 seconds. When the first trigger is fired, the pressure to the left of the second injection line becomes uniform, which is normal since the first injection line is closed; meaning that end of the part becomes an impermeable wall. Similar images are also given for the second trigger. TUTORIALS Sequential Injection (Trigger Manager) PAM-RTM 2014 © 2014 ESI Group 381 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Sequential Injection (Trigger Manager) USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Sequential Injection (Trigger Manager) 382 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 383 USER’S GUIDE & TUTORIALS (released: Apr-14) VELOCITY OPTIMIZATION The following files are used in this example. - velo_opti_start.unv (starting mesh) - velo_opti.dtf + velo_opti.unv (solution) Objectives The goal of this tutorial is to show how to use the velocity optimization option, in order to minimize the final void content in a part. Process and Numerical Parameters The following assumes the user already has from experimental measurements, relations for the micro and macro void content as a function of the flow velocity. The relations used in this example are shown below. The curve with the negative slope is the macro void function, the other one is the micro void function. Looking at these curves, we can see that the optimal void content is around 2%. 14% Chomarat - Roviply 12% 12.824-1573.7*(V) 20 psi 30 psi 45 psi 2,5 ml/s Voids content 10% 8% 6% 1.26+100.55*(V) 4% 2% 0% 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02 Flow velocity (m/sec) Note that normally we would work with curves that are functions of the capillary number. However in this case since the resin viscosity (0.02 Pa.s) is the same as the capillary coefficient, the capillary number actually reduces to the resin velocity. TUTORIALS Velocity optimization USER’S GUIDE & TUTORIALS (released: Apr-14) 384 PAM-RTM 2014 © 2014 ESI Group Begin by creating a new RTM simulation. The most important parameters for velocity optimization are located in the Velo Opti tab of the Process dialog box. Double-click on the Process item in the document’s tree to open the process dialog box. Enter the following values in the Velo Opti tab: - Optimize velocity checked - Resin capillary coefficient: 0.02 - Optimal capillary number: 0.0069 - Micro voids function: linear with A = 100.5, B = 1.27 - Macro voids function: linear with A = -1574, B = 12.82 - Nb max iter: 3 - Tolerance: 1e-4 This is shown below. The next step is to tell PAM-RTM to save the results files related to velocity optimization: capillary numbers, micro voids, macro voids, and a file containing the sum of micro and macro void values. The saving of these 4 files is controlled by a single option: save capillary numbers in the Output tab of the Numerical parameters dialog box. TUTORIALS Velocity optimization PAM-RTM 2014 © 2014 ESI Group 385 USER’S GUIDE & TUTORIALS (released: Apr-14) Material Properties Enter the following material and zone properties: - viscosity: 0.02 Pa.s - Permeability: k1 = k2 = k3 = 1e-9 m2 - Porosity: 0.5 - Thickness: 0.005 m Boundary Conditions The provided mesh already contains 2 groups, as shown below. Group 1 is used as the inlet, and group 2 as the outlet. Define a pressure boundary condition of 0.1 bar (10 000 Pa) on group 1. Define a vent boundary condition with zero pressure on group 2. TUTORIALS Velocity optimization USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Velocity optimization 386 PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 387 USER’S GUIDE & TUTORIALS (released: Apr-14) Launching the Simulation and Post-processing We will run 2 simulations in this tutorial: the first one without the optimize velocity option, the second one with the option, to better understand its effect. For the first case, simply uncheck optimize velocity in the Velo Opti tab of the Process parameters, leaving all the other parameters the same. It is important to understand that it makes sense to run a simulation with all the parameters in the Velo Opti tab defined, but without the optimize velocity option active. This is useful to visualize the void content at the end of the injection that you would have if you didn’t optimize velocity. Save the document with File->Save, giving it a name so you can remember that the case was run without the optimization, then launch the simulation. When the simulation is done, load all the results files in a single click by pushing the Reload results button in the main toolbar. You should have the following. For the first case, uncheck “optimize velocity” TUTORIALS Velocity optimization USER’S GUIDE & TUTORIALS (released: Apr-14) 388 PAM-RTM 2014 © 2014 ESI Group Micro voids percent at the end of filling for the first case (no optimization). Macro voids percent at the end of filling without optimization. TUTORIALS Velocity optimization PAM-RTM 2014 © 2014 ESI Group 389 USER’S GUIDE & TUTORIALS (released: Apr-14) Capillary number Total voids percent (micro + macro voids) TUTORIALS Velocity optimization USER’S GUIDE & TUTORIALS (released: Apr-14) 390 PAM-RTM 2014 © 2014 ESI Group Velocity field at the end of filling (v = 2.5e-3 m/s) It is important to understand that the micro voids, macro voids and capillary number results are non-transient (single step) fields. This is because the model relates the void content to the velocity at the exact time when the resin front touches an element, and it is assumed that void content doesn’t change for the rest of the simulation once it is set on an element. For the second case, reactivate the optimize velocity option. Save the file with Save As, with a new name so you can remember that the case was run with the optimize option. When the simulation is done, push the Reload results button. You should have the following. Notice that the micro voids result of 1.96% matches the value expected from the curves shown at the beginning of this tutorial. For this simple case, the macro voids results remain always zero. This is because with this void model, for a given velocity, it is not possible to have micro and macro voids at the same time. This implies that if an element has a non-zero micro void value, its TUTORIALS Velocity optimization PAM-RTM 2014 © 2014 ESI Group 391 USER’S GUIDE & TUTORIALS (released: Apr-14) macro void value will be zero, and vice versa. On this case, the velocity optimization algorithm always converges to a velocity value slightly in the micro voids area, leading to a macro void value of zero. On more complex cases, the optimal void values would be scattered between the micro and macro void results. Finally notice that the velocity at the end of injection (6.9e-3 m/s) is much higher than the previous case (2.5e-3 m/s). This is because PAM-RTM had to convert the pressure imposed inlet to a flow rate imposed inlet, to be able to reach the optimal velocity. Micro voids result with optimization TUTORIALS Velocity optimization USER’S GUIDE & TUTORIALS (released: Apr-14) 392 Macro voids result with optimization Capillary number with optimization TUTORIALS Velocity optimization PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 393 USER’S GUIDE & TUTORIALS (released: Apr-14) Velocity at the end of filling (v = 6.9e-3 m/s) TUTORIALS Velocity optimization USER’S GUIDE & TUTORIALS (released: Apr-14) 394 PAM-RTM 2014 © 2014 ESI Group COMPRESSION RTM The following files are used in this example: - crtm_start.unv (starting mesh); - crtm_rtm.dtf + crm_rtm.unv + crtm.dtf + crtm.unv (solution). Objective The objective of this tutorial is to show how to define a compression RTM data set-up. Compression RTM module is made to simulate the kind of process in which a compression of the reinforcement is used to push the resin inside the cavity. This tutorial is limited to a case where only one tool is in movement, but Compression RTM module can treat more complex kinematics. Geometry and Boundary Conditions The part is a hood made of a unique zone (zone 2), which is injected from a single point in the center of the part (group 1), with two vents (group 2) at the corners of the part. Groups TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 395 USER’S GUIDE & TUTORIALS (released: Apr-14) Two simulations will be carried out to obtain this result: - standard RTM injection simulation with a set thickness , which is the final part thickness objective calculated so that fiber content of the part is 50%, to determine the volume of resin to inject; - compression RTM simulation using this resin volume. Material Characteristics Resin viscosity will be set constant equal to default resin viscosity: 0.1Pa.s The reinforcement is created with the following characteristics required for Compression RTM set-up and is saved in the database. In the case of Compression RTM, permeability is a function of fiber content like in the VARI case. But unlike VARI, compressibility curve and natural thickness are not used, as thickness of the cavity is set by the gap between the two tools. Fiber content of each zone will be computed from this thickness, density and superficial density. Reinforcement characteristics TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 396 PAM-RTM 2014 © 2014 ESI Group Permeability function of fiber content is set isotropic and is defined with the following formula. Permeability curve This material is added to the material database so that it can be imported in next case. RTM Injection Data Set-up An RTM injection case is created; the mesh crtm_start.unv is imported. The reinforcement characteristics are defined as seen before. The objective for final fiber content is 50%. The thickness is computed from this thickness; it is equal to 4.48mm (=5.6/(2500*0.5)). TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 397 USER’S GUIDE & TUTORIALS (released: Apr-14) Zone definition Injection pressure is set to 5 bars on group 1, and the vent pressure is set to zero on group 2. The vents are opened during the complete process. Boundary condition definition TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 398 PAM-RTM 2014 © 2014 ESI Group Post-treatment The filling time is 111s, and the injected volume is equal to 3.13 liters. This volume will be used in the compression RTM set-up. Log file - Injected volume Filling time TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 399 USER’S GUIDE & TUTORIALS (released: Apr-14) Compression RTM Injection Data Set-up A new data set-up of type Compression RTM is created. Compression RTM set-up creation The following assumptions are made for CRTM simulation in Pam-Rtm: - 2D mesh is used, and thickness is a variable of each element; - reinforcement always fills complete the mold cavity, and there is no surface channel on top of the reinforcement; - distance between the fixed tool and the moving tool is the thickness of each element. The mesh needs to be imported from the previous case. The reinforcement material is imported from the material database. The pressure and vent boundary conditions need to be redefined. TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 400 PAM-RTM 2014 © 2014 ESI Group Compression Boundary Condition In both case, it is necessary to create a group on which compression will be defined. This group is a group of faces, which will contain all the faces of the model since compression is defined on the whole surface. This group will represent the tool that will move during compression. Face selection Group created Compression boundary condition and compression process parameters The compression process set-up will involve two modifications in the set-up: - in the process parameters will be defined; the compression direction and the mold opening, which is the gap ; - in the boundary condition will be defined; the closing velocity of the tool and the timing of the closing (start/stop state). The group that closes as well as the closing velocity are defined in the Compression boundary condition. The closing of the mold is controlled with a trigger. - compression velocity is equal to 0.4mm/min=6.67.10-6m/s; - state is set to 0 initially, since this boundary condition will be activated using a trigger. Closing of the mold will start when enough resin has been injected. TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 401 USER’S GUIDE & TUTORIALS (released: Apr-14) Compression boundary condition Other compression process parameters are defined in the Process dialog box in the Compression RTM tab - mold opening is set to 5mm; - compression direction is set to +Z vector Compression process parameters TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 402 PAM-RTM 2014 © 2014 ESI Group Trigger Definition The compression boundary condition is controlled by one trigger: - volume trigger that will stop injection and start compression when the needed resin volume has been injected ; the volume is set to 3.16l to ensure enough resin is injected, The trigger is a volume trigger that does not require the use of a sensor. A sensor is created that can be used for post-treatment. Sensor creation Triggers definition TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 403 USER’S GUIDE & TUTORIALS (released: Apr-14) Zone Definition Zone parameters set are thickness and porosity. In the case of CRTM, thickness is the final thickness of the part, that is when the mold is closed. Porosity parameter is not used and is computed from thickness value during the process in the same way as it is computed for VARI process: fiber content = 1 – porosity = superficial density / (density * thickness) Initial thickness for each element is computed as initial thickness = final thickness + mold opening * cos(alpha) where alpha is the angle between compression direction and element normal as shown on picture below. This formula is also used to compute thickness of the reinforcement at any time during compression. compression direction n alpha h2 h1 (initial mold opening) hf (final thickness) hf hf h1 hf hf TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 404 Zone definition Post-Treatment It can be verified in the log file that compression starts after 2.7s, and that injected volume is 3.16l. Filling time is 77.5s. TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 405 USER’S GUIDE & TUTORIALS (released: Apr-14) Filling time TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 406 PAM-RTM 2014 © 2014 ESI Group Flow front position is visualized at the end of injection at 2.75s, and during compression. End of injection During compression Thickness variation at the sensor position is plotted. Sensor thickness TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 407 USER’S GUIDE & TUTORIALS (released: Apr-14) Pressure position is visualized at the end of injection, during compression, and at the end of compression. Pressure at the end of compression is higher than the injection pressure End of injection During compression End of injection TUTORIALS Compression RTM USER’S GUIDE & TUTORIALS (released: Apr-14) 408 PAM-RTM 2014 © 2014 ESI Group Conclusion This tutorial has shown how to model CRTM process in which impregnation of the part is divided in two phases: - injection phase where reinforcement thickness is larger than final part thickness so that permeability is increased; - resin is pushed inside the part by compression. TUTORIALS Compression RTM PAM-RTM 2014 © 2014 ESI Group 409 USER’S GUIDE & TUTORIALS (released: Apr-14) LOCAL PERMEABILITY FROM DRAPING RESULTS The following files are used in this example. - drape.dsy (PAM-FORM™ result file, 1 ply) - drape_start.unv (injection mesh file) Introduction The filling simulation in PAM-RTM™ is macroscopic based on Darcy’s law, where the permeability values of the fiber preform play a very important role. During the preforming process, such as draping, the local permeability of the preform may change due to the local fiber shearing, slipping, nesting, etc. This tutorial demonstrates the complete procedure for using draping results in a PAM-RTM™ filling simulation. In summary, it is carried out in the following steps: - Import draping results in PAM-RTM™: imports the draped plies generated by the draping software in the current document. - Map draping results: projects draped plies on the injection mesh. The goal of this step is to calculate the geometrical correspondence between an element of the injection mesh and elements of the draped plies meshes. - Local permeability calculation: generate the local permeability and porosity distribution on the injection mesh taking into account the fiber directions of the draped plies. PAM-RTM™ has direct interface with four draping simulation tools : PAM-FORM™ and PAM-QUIKFORM™ (ESI Group), PATRAN Laminate Modeler (MSC), FiberSIM (Vistagy). Without losing generality, a bathtub-like geometry is chosen in this tutorial with the draping results obtained from PAM-FORM™, as shown below. It is important to understand that, even if we work with PAM-FORM™ results here, the procedure is the same for the FiberSIM, PATRAN Laminate Modeler and PAMQUIKFORM™ interfaces. TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 410 PAM-RTM 2014 © 2014 ESI Group Map Draping Results Create a new RTM simulation with File->New. Import the mesh file for the injection simulation drape_start.unv. To import the draping results, select File->Import->Draping Results->PAM-FORM. The Import PAM-FORM Laminate dialog box pops up. Select the PAM-FORM™ file drape.dsy, and click Open. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 411 USER’S GUIDE & TUTORIALS (released: Apr-14) The imported plies are listed in the Draping Results folder of the explorer. It can be useful to visualize one of the imported plies on top of the injection mesh. Right-click on the layer to visualize and choose View Layer. TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 412 PAM-RTM 2014 © 2014 ESI Group It is also possible to have the ply edges colored based on shear angle. Choose Shear_Angle in the scalar fields combo box. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 413 USER’S GUIDE & TUTORIALS (released: Apr-14) It is also possible to visualize a ply in its own 3D window, with the command New Window in the explorer. This gives more post-processing options. For example, with the first approach, only the edges are colored. With the New Window approach, the faces are colored so it is possible to obtain a contour. TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 414 PAM-RTM 2014 © 2014 ESI Group The Window menu lists all open documents. Notice that a ply visualization activated with the New Window command is actually considered a document. It has the same name as the injection document, with the layer index appearing between parenthesis. Select the appropriate document to go back to the injection mesh. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 415 USER’S GUIDE & TUTORIALS (released: Apr-14) Activate the injection mesh display window. Use the command Mesh->Orientations>Map Draping Results to perform the mapping calculation from the draped plies to the injection mesh. The mapping calculation can be carried out on the full injection mesh or on the currently selected elements only. This is useful for example to avoid plies to be mapped into zones used for runners in the injection mesh. If some elements are selected when TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 416 PAM-RTM 2014 © 2014 ESI Group you launch Map Draping Results, PAM-RTM™ asks for a confirmation that the mapping is to be done only on the selected elements. Then a dialog box pops up for the normal max distance. The units are the same as the length units of the model. Since we are currently working on a mesh in millimeters, enter a of normal max distance of 1.5 mm. This parameter is useful for instance on ribbed parts, to avoid elements on one rib to be mapped on another front facing rib. See the chapter describing the commands of the Mesh menu in the PAM-RTM™ user’s guide for more information. Click OK, and the mapping calculation starts. A progress dialog box appears. Since mapping calculations are typically very long, it is possible to stop the calculation with the Cancel button. After the mapping calculation finishes, select Nb_Plies in the scalar field roll-down list, the number of laminate plies mapped to each element of the injection mesh is displayed. This is useful to verify the results of the mapping calculation. Since in this example, only one ply that covers completely the injection mesh was mapped, Nb_Plies must be equal to 1 everywhere. Otherwise you would have to adjust the tolerances. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 417 USER’S GUIDE & TUTORIALS (released: Apr-14) Select Shear_Angle in the scalar field roll-down list and Iso in the plot type roll-down list, and turn off the Edge display. The mapped shearing angle distribution from the first laminate ply on the injection mesh is shown in the current display window. TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 418 PAM-RTM 2014 © 2014 ESI Group Local Permeability Calculation The command Mesh->Orientations->Compute Local Permeability computes the average permeability and porosity on each element of the injection mesh, using the results of the Map Draping Results calculation. To calculate local permeability, PAM-RTM™ needs to know the type of reinforcement and permeability model associated to each ply, as well as the initial fiber content of each ply. This is done using laminates. Before launching Compute Local Permeability, the user has to create a laminate material matching the imported plies, i.e. with the same number of plies. For this example, make sure that the initial porosity of layer 1 of the laminate is 0.5. This is the porosity before shearing. Set the permeability of the fabric linked to layer 1 (default fabric) to 1.10-11 m². Now you can launch Mesh->Orientations->Compute Local Permeability. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 419 USER’S GUIDE & TUTORIALS (released: Apr-14) The Permeability Model dialog box pops up. In this example, we want the permeability calculation to be based on the imported PAM-FORM™ ply, so check use imported plies. We assume in this example that the permeability of the undeformed fabric is isotropic. Choose the Isotropic Woven Fabric model in the permeability model for sheared fabrics roll-down list, then click OK to start the local permeability calculation. To view the local permeability calculation results, select porosity in the main toolbar’s roll-down list. Then the local porosity field on the injection mesh is displayed. TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 420 PAM-RTM 2014 © 2014 ESI Group The K1 principal direction can be displayed by selecting View->Orientations->K1. Switch off the scalar field display by selecting Default_Color in the scalar field rolldown list. The K1 direction is displayed in the following image with red arrows. Contours for K1 and K2 in the high shearing areas are shown below. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 421 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 422 PAM-RTM 2014 © 2014 ESI Group Filling Simulation In the RTM Numerical Parameters dialog box, select Use local permeability files and Use local porosity file. We do not use the local thickness file in this example. We just assume a constant thickness cavity, specified in zone 2 of the injection mesh. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 423 USER’S GUIDE & TUTORIALS (released: Apr-14) Normally, since local permeability files are used, there is no need to specify the permeability values using the fabric editor. However it is recommended to specify reasonable values for K1, K2 and K3, because if for some reason the value for an element is not found in the local permeability file, the value specified in the fabric editor will be used. The following groups have to be created. TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 424 PAM-RTM 2014 © 2014 ESI Group To summarize, here are the parameters that need to be set for the filling simulation: - resin: · - - - - viscosity: 0.1 Pa.s fabric: · name: Default Fabric · K1: 1.10-11 m2 · K2: 1.10-11 m2 · K3: 1.10-11 m2 zone: · ID : 2 · material: Default Fabric · porosity: 0.5 · thickness: 0.005 m boundary condition : · ID: 1 · type: pressure · pressure value: 3.105 Pa boundary condition: · ID: 2 · type: vent · pressure value: 0 Pa · state: Finally, save the PAM-RTM document before starting the simulation. Since a compute local permeability was done, some files will be automatically generated in the same directory as the x.dtf file: x_k1.sf, x_k2.sf, x_porosity.sf. These are the files read by the PAM-RTM™ solver to initialize local permeability and porosity. When saving the files, PAM-RTM™ detects that the span of the injection mesh is very large, which could mean that it is defined in millimeters, so it asks whether you want to automatically convert it to meters. Select Yes. Launch the simulation. When it is done, load the results files. You should have the following segmented filling patterns. Filling time is about 692 seconds. TUTORIALS Local Permeability from Draping Results PAM-RTM 2014 © 2014 ESI Group 425 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Local Permeability from Draping Results USER’S GUIDE & TUTORIALS (released: Apr-14) 426 PAM-RTM 2014 © 2014 ESI Group LOCAL PERMEABILITY FROM DRAPING RESULTS (ADVANCED) The following files are used in this example. - drape2.dsy (4 plies laminate file) - drape2_start.unv - drape2_K1.srf (sheared permeability K1 kriged function data file) - drape2_K2.srf (sheared permeability K2 kriged function data file) - drape2_beta.srf (injection mesh file) (sheared rotation angle kriged function data file) Objectives This document presents an advanced tutorial on local permeability calculation from draping results, complementary to the previous tutorial – Local permeability from draping results. The advanced features include - how to assign materials to a more complex laminate made of many plies, - how to use kriged functions to describe the fabric sheared permeability as a function of shear angle and fiber content. The same bathtub-like geometry used in the previous tutorial is investigated again in this tutorial with the draping results of a 4 plies laminate obtained with PAMFORM™, and the geometry is shown below. TUTORIALS Local Permeability from Draping Results (Advanced) PAM-RTM 2014 © 2014 ESI Group 427 USER’S GUIDE & TUTORIALS (released: Apr-14) Map Draping Results Create a new RTM simulation with File->New. Import the mesh file drape2_start.unv. Then select File->Import->Draping Results->PAM-FORM to import the draping results file drape2.dsy. There are four plies in the draping file. They are listed in Draping Results folder of the explorer after importation. Right-click on the Draping Results item and choose View Multiple to allow visualization of many layers in the same window. Then right-click on the first layer and choose View Layer. TUTORIALS Local Permeability from Draping Results (Advanced) USER’S GUIDE & TUTORIALS (released: Apr-14) 428 PAM-RTM 2014 © 2014 ESI Group Do the same for the fourth layer. This leads to the following picture, where we can see clearly that there is an offset between the first and fourth ply. This will be important for the transverse tolerance when mapping draping results. All the four plies in this PAM-FORM™ file have a zero degree orientation, so all the plies have similar local deformations, but not exactly the same because of the thickness of the part. The figure below shows the shear angle distribution for ply 2. Go back to the injection mesh window. Select Mesh->Orientations->Map Draping Results to perform the mapping calculation from the imported draped plies to the injection mesh. In the Mapping Parameters dialog box, enter 4.0 (mm) as normal max distance. TUTORIALS Local Permeability from Draping Results (Advanced) PAM-RTM 2014 © 2014 ESI Group 429 USER’S GUIDE & TUTORIALS (released: Apr-14) When the mapping calculation is done, the mapped shearing angle distribution from the first laminate ply on the injection mesh is shown as below. Select Nb_Plies in the scalar field roll-down list to view the number of laminate plies mapped to each element of the injection mesh. Since in this example, four plies that cover completely the injection mesh were mapped, Nb_Plies must be equal to four everywhere. TUTORIALS Local Permeability from Draping Results (Advanced) USER’S GUIDE & TUTORIALS (released: Apr-14) 430 PAM-RTM 2014 © 2014 ESI Group Local Permeability Calculation Before we can launch the local permeability calculation, we have to specify material properties for each of the imported draped plies. To do so, we first create a laminate material made of four layers, to match the four imported draped plies. Right-click the first layer of the Default Laminate, then choose Insert Above to add a layer above the selected one. Repeat this procedure until you have four layers. TUTORIALS Local Permeability from Draping Results (Advanced) PAM-RTM 2014 © 2014 ESI Group 431 USER’S GUIDE & TUTORIALS (released: Apr-14) All four layers reference the Default Fabric. Double-click Default Fabric to open the fabric editor. In the Advanced tab, we will specify a sheared permeability model with the fields Sheared Permeability K1, Sheared Permeability K2, Sheared Permeability K3, and Sheared Rotation Angle, where sheared permeability K1, K2, and K3 are 1st, 2nd, and 3rd principal direction of the permeability tensor, respectively. Click on the … button to the right of the Sheared Permeability K1 field to open the Function Editor dialog box. Select Import from file and in the Import dialog box, choose in the Type roll-down list PAM-RTM (*.srf) and browse to drape2_k1.srf. By the same way, set the fields Sheared permeability K2 and Sheared rotation angle. Before closing the Function Editor dialog box, don’t forget to select the imported function. TUTORIALS Local Permeability from Draping Results (Advanced) USER’S GUIDE & TUTORIALS (released: Apr-14) 432 PAM-RTM 2014 © 2014 ESI Group The user could also enter the data points manually. The x column is the shear angle (in degree), y is the fiber content (a decimal value between 0 to 1), and z is the sheared permeability (unit: m2). The sheared rotation angle designates the angular position of 1st principal direction of the permeability tensor (K1) with respect to the warp direction of the laminate fabric (f1), as shown in the following figure. K2 f2 K1 β TUTORIALS Local Permeability from Draping Results (Advanced) f1 PAM-RTM 2014 © 2014 ESI Group 433 USER’S GUIDE & TUTORIALS (released: Apr-14) Note · If you select View->Orientations->K1 Only (or K2 Only) when the active window is a draped ply, the K1 direction represents the warp direction of a fabric, and K2 represents the weft direction. However if you visualize K1 on the injection mesh after Compute Local Permeability, the K1 direction is the 1st principal direction of the permeability tensor. So the same command View->Orientations>K1 is used to visualize fiber directions or principal permeability directions, depending on the context. The sheared permeability K1, sheared permeability K2 and sheared rotation angle functions used in this example are displayed below. TUTORIALS Local Permeability from Draping Results (Advanced) USER’S GUIDE & TUTORIALS (released: Apr-14) 434 PAM-RTM 2014 © 2014 ESI Group For 3D simulations, the Sheared Permeability K3 could also be defined as a function of the fiber content and shear angle, if such experimental data is available. In this example, we set Sheared Permeability K3 to a constant value. To perform the local permeability calculation, select Mesh->Orientations->Compute Local Permeability. TUTORIALS Local Permeability from Draping Results (Advanced) PAM-RTM 2014 © 2014 ESI Group 435 USER’S GUIDE & TUTORIALS (released: Apr-14) The Compute Local Permeability dialog box pops up. Check use imported plies and select Woven Fabric in the permeability model roll-down list, which means that the sheared permeability functions we’ve just defined will be used. The figure below shows the 1st principal direction of the permeability tensor after local permeability calculation. The following figures show the local porosity and local K1 value after mapping calculation. TUTORIALS Local Permeability from Draping Results (Advanced) USER’S GUIDE & TUTORIALS (released: Apr-14) 436 PAM-RTM 2014 © 2014 ESI Group The rest of the procedure is the same as described in the tutorial Local permeability from draping results. The following figure shows the filling pattern at a constant pressure injection, whose injection and vent conditions are the same as in the previous tutorial. TUTORIALS Local Permeability from Draping Results (Advanced) PAM-RTM 2014 © 2014 ESI Group 437 USER’S GUIDE & TUTORIALS (released: Apr-14) TUTORIALS Local Permeability from Draping Results (Advanced) USER’S GUIDE & TUTORIALS (released: Apr-14) 438 PAM-RTM 2014 © 2014 ESI Group PAM-QUIKFORM The following files are used in this example. - quikform_start.ps (starting mesh) - quikform.dtf + quikform.ps (solution) Objectives The goal of this tutorial is to show how to perform a draping simulation using the PAM-QUIKFORM™ user interface available in PAM-RTM™. The geometry used is a double hemisphere. We will drape a laminate made of two plies of fabric and two plies of unidirectional. The contact point is the top of the big hemisphere and the laminate reference axis (zero degree) is the global X axis. Process and Numerical Parameters Create a new PAM-QUIKFORM simulation with File->New->PAM-QUIKFORM. Import the mesh file quikform_start.ps with File->Import->Mesh. Make sure to set the file filter to PAM-SYSTEM, as shown below. TUTORIALS PAM-QUIKFORM PAM-RTM 2014 © 2014 ESI Group 439 USER’S GUIDE & TUTORIALS (released: Apr-14) First we create a draping referential (also called axis in PAM-RTM™) on top of the big hemisphere. The default PAM-QUIKFORM document contains an axis located at the origin. It is unlikely that this axis is what you want, so double-click the default axis to open the Axis Definition dialog box. TUTORIALS PAM-QUIKFORM USER’S GUIDE & TUTORIALS (released: Apr-14) 440 PAM-RTM 2014 © 2014 ESI Group Push the Pick button [1] and pick a point near the top of the big hemisphere, or enter the coordinates of the origin manually (0, 0, 150). The direction vector is the local X axis of the draping referential, i.e. the axis on which zero degree plies will be aligned. The local Y and Z axis are set automatically by PAM-RTM™. The local Z axis is the normal vector on the picked point and the local Y axis is calculated to have a right-hand coordinate system. If you want the opposite local Z direction, use the command Reverse Z, available in the explorer when right-clicking an axis. In this tutorial, we keep the default direction vector (1, 0, 0), then we reverse the local Z axis to have it in the global Z+ direction, as shown below. Now we have to define the following laminate: - layer 4: 90 degrees fabric - layer 3: -45 degrees unidirectional - layer 2: +45 degrees unidirectional - layer 1: zero degree fabric TUTORIALS PAM-QUIKFORM PAM-RTM 2014 © 2014 ESI Group 441 USER’S GUIDE & TUTORIALS (released: Apr-14) Right-click Layer 1 in the Default Laminate and insert three layers above. Edit each layer by double-clicking it, then set the material and angle as specified above. Finally you should have the following laminate in the explorer. TUTORIALS PAM-QUIKFORM USER’S GUIDE & TUTORIALS (released: Apr-14) 442 PAM-RTM 2014 © 2014 ESI Group After having specified a draping referential and laminate, we would normally have to specify operations in the Process folder. Operations are used in the PAM-QUIKFORM interface of PAM-RTM™ to associate a laminate to a draping referential, and also optionally to select a group of elements on which draping is to be done. In this tutorial, we just use the Default Operation, which refers to Default Axis and Default Laminate. TUTORIALS PAM-QUIKFORM PAM-RTM 2014 © 2014 ESI Group 443 USER’S GUIDE & TUTORIALS (released: Apr-14) Finally, before launching the PAM-QUIKFORM simulation, we have to set some numerical parameters, the most important ones being grid size u and grid size v. These are the size of the elements of the draped plies meshes. The default size is zero, which means that it is unspecified and that PAM-QUIKFORM will calculate a size to get a reasonable mesh. In this example, we force the element size to 5 mm in the u and v directions. Launching the Simulation and Post-Processing Before the simulation can be launched, the PAM-QUIKFORM document must be saved with File->Save. To launch the simulation, use the green arrow button in the toolbar [1]. When the simulation is done, PAM-RTM™ loads automatically all the draped plies meshes and lists them in the Draping Results folder of the explorer. Right-click one of the layers and choose View Layer to visualize the mesh of the layer on top of the tool mesh. It is possible to visualize many layers in the same window with the command View Multiple of the Draping Results popup menu. TUTORIALS PAM-QUIKFORM USER’S GUIDE & TUTORIALS (released: Apr-14) 444 PAM-RTM 2014 © 2014 ESI Group Using this approach for visualization of layers, here is what you should have for layers 1 to 3 (since layer 4 is a 90 degrees fabric, and since it is not possible to display warp and weft with different colors, there is no difference with layer 1). Layer 1 (zero degree fabric) TUTORIALS PAM-QUIKFORM PAM-RTM 2014 © 2014 ESI Group 445 USER’S GUIDE & TUTORIALS (released: Apr-14) Layer 2 (+45 degrees UD) Layer 3 (-45 degrees UD) TUTORIALS PAM-QUIKFORM USER’S GUIDE & TUTORIALS (released: Apr-14) 446 PAM-RTM 2014 © 2014 ESI Group When a layer is visualized with View Layer, the tool mesh is forced to default color and the variables available in the scalar field combo box control coloring of the layer mesh edges. Choosing Shear_Angle [1] leads to the figure below. Edges colored with shear angle TUTORIALS PAM-QUIKFORM PAM-RTM 2014 © 2014 ESI Group 447 USER’S GUIDE & TUTORIALS (released: Apr-14) The New Window command, available when right-clicking a layer in the Draping Results folder, is used to visualize the mesh of a layer in its own 3D window. This gives access to more post-processing options. For example, it is possible to generate contours of the shear angle, as shown below, which is not possible when the layer is visualized in the tool window. Shear angle contours Finally, it is possible to visualize the mesh of the 2D flat pattern of a layer by choosing the command New Window (Flat Pattern). To get a more accurate representation of the boundary of the flat pattern, you can activate the Flat curve option in the numerical parameters. This option calculates the green curve shown below. TUTORIALS PAM-QUIKFORM USER’S GUIDE & TUTORIALS (released: Apr-14) 448 2D flat pattern of layer 1 TUTORIALS PAM-QUIKFORM PAM-RTM 2014 © 2014 ESI Group PAM-RTM 2014 © 2014 ESI Group 449 USER’S GUIDE & TUTORIALS (released: Apr-14) 2D flat pattern of layer 1 with flat curve option Credits Twente University, Netherlands, for the tool geometry. Cranfield University, UK, for the mesh. TUTORIALS PAM-QUIKFORM
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