Quick Fatigue Tool User Guide

• User Guide
• Version Information
• Acknowledgements
• 1. Introduction
  • 1.1 Overview
  • 1.2 The stress-life methodology
  • 1.3 The strain-life methodology
  • 1.4 Why fatigue from FEA?
  • 1.5 Overview of syntax
    • 1.5.1 Overview
    • 1.5.2 Job file options
    • 1.5.3 Environment variables
    • 1.5.4 Units
    • 1.5.5 Documentation conventions
  • 1.6 Required toolboxes
  • 1.7 Limitations
    • 1.7.1 Fatigue from FEA
    • 1.7.2 Loading
    • 1.7.3 Materials
    • 1.7.4 Performance
    • 1.7.5 GUI appearance
    • 1.7.6 Validation
  • 1.8 Additional notes
• 2. Getting started
  • 2.1 Preparing the application
  • 2.2 How the application handles variables
  • 2.3 File structure
  • 2.4 Configuring and running an analysis
    • 2.4.1 Configuring a standard analysis
    • 2.4.2 Configuring a data check analysis
    • 2.4.3 Configuring an analysis from a text file
  • 2.5 The analysis method
• 3. Defining fatigue loadings
  • 3.1 Loading methods
    • 3.1.1 Overview
    • 3.1.2 Syntax
    • 3.1.3 Uniaxial history
    • 3.1.4 Simple Loading
    • 3.1.5 Multiple load history (scale and combine) loading
    • 3.1.6 Dataset sequences
    • 3.1.7 Complex (block sequence) loading
  • 3.2 Creating a stress dataset file
    • 3.2.1 Dataset structure
    • 3.2.2 Creating a dataset from Abaqus/Viewer
    • 3.2.3 Creating datasets from other FEA packages
    • 3.2.4 Creating datasets with different element types
    • 3.2.5 Specifying stress dataset units
  • 3.3 Creating a load history
  • 3.4 Load modulation
  • 3.5 High frequency loadings
    • 3.5.1 Overview
    • 3.5.2 Defining high frequency loadings
    • 3.5.3 Example usage
    • 3.5.4 Additional guidance
  • 3.6 The dataset processor
    • 3.6.1 Determining the dataset type
    • 3.6.2 Plane stress elements
    • 3.6.3 Multiple element groups
• 4. Analysis techniques
  • 4.1 Background
  • 4.2 Treatment of nonlinearity
    • 4.2.1 Overview
    • 4.2.2 Limitations of the nonlinear model
  • 4.3 Surface finish and notch sensitivity
    • 4.3.1 Surface finish
    • 4.3.2 Effect of notch sensitivity
    • 4.3.3 Modelling guidance
  • 4.4 In-plane residual stress
    • 4.4.1 Overview
    • 4.4.2 Limitations
  • 4.5 Analysis speed control
    • 4.5.1 Pre-processing time histories
    • 4.5.2 Determining load proportionality
    • 4.5.3 Specifying the analysis region
    • 4.5.4 Nodal elimination
    • 4.5.5 Principal stress calculation
  • 4.6 Analysis groups
    • 4.6.1 Overview
    • 4.6.2 Defining analysis groups as an item ID list
    • 4.6.3 Defining analysis groups as an FEA subset
    • 4.6.4 Arranging groups in the job file
    • 4.6.5 Assigning properties to groups
    • 4.6.6 Limitations
  • 4.7 S-N knock-down factors
    • 4.7.1 Overview
    • 4.7.2 Defining a knock-down curve file
    • 4.7.3 Example applications
    • 4.7.4 Exporting knock-down curves
  • 4.8 Analysis continuation techniques
    • 4.8.1 Overview
    • 4.8.2 Referencing the previous job
    • 4.8.3 Example applications
    • 4.8.4 Additional guidance
    • 4.8.5 Limitations
  • 4.9 Virtual strain gauges
    • 4.9.1 Overview
    • 4.9.2 Gauge definition
    • 4.9.3 Technical background
    • 4.9.4 Specifying the position of the strain gauge
    • 4.9.5 Specifying the orientation of the strain gauge
    • 4.9.6 Example usage
    • 4.9.7 Modelling guidance
    • 4.9.8 Limitations
• 5. Materials
  • 5.1 Background
    • 5.1.1 Overview
    • 5.1.2 Accessing the Material Manager
  • 5.2 Material databases
    • 5.2.1 Overview
    • 5.2.2 Specifying the local material database
  • 5.3 Using material data for analysis
    • 5.3.1 Specifying the material in the job file
    • 5.3.2 Fetching materials from the system database
  • 5.4 Creating materials using the Material Manager
    • 5.4.1 Overview
    • 5.4.2 Units
  • 5.5 Creating materials from a text file
    • 5.5.1 Overview
    • 5.5.2 Material keyword syntax
    • 5.5.3 Importing materials from a text file
    • 5.5.4 Specifying material properties in a job file
    • 5.5.5 Material keyword reference
  • 5.6 General material properties
    • 5.6.1 Overview
    • 5.6.2 Default analysis settings
    • 5.6.3 Treatment of fully-compressive cycles
  • 5.7 Fatigue material properties
    • 5.7.1 Overview
    • 5.7.2 Fatigue constants
    • 5.7.3 Fatigue test data
    • 5.7.4 Defining the fatigue limit for fatigue test data
  • 5.8 Composite material properties
    • 5.8.1 Overview
    • 5.8.2 Defining properties for stress-based failure criteria
    • 5.8.3 Defining properties for the maximum strain failure theory
    • 5.8.4 Defining properties for Hashin’s damage initiation criteria
    • 5.8.5 Defining properties for the LaRC05 damage initiation criteria
  • 5.9 Estimation techniques
    • 5.9.1 Approximating material data
    • 5.9.2 Disabling material data approximation
    • 5.9.3 Defining material behavior
    • 5.9.4 Defining material classification
• 6. Analysis algorithms
  • 6.1 Background
  • 6.2 Stress-based Brown-Miller
    • 6.2.1 Overview
    • 6.2.2 Using stress-life data
    • 6.2.3 Cycle counting
    • 6.2.4 Proportional loading
  • 6.3 Normal Stress
    • 6.3.1 Overview
    • 6.3.2 Critical plane searching
  • 6.4 Findley’s Method
    • 6.4.1 Overview
    • 6.4.2 Determining the value of ,,𝝉-𝒇.-∗.
    • 6.4.3 Determining the value of 𝒌
    • 6.4.4 Critical plane searching
    • 6.4.5 Output
    • 6.4.6 Limitations
  • 6.5 Stress Invariant Parameter
    • 6.5.1 Overview
    • 6.5.2 Effective stress parameters
    • 6.5.3 Specifying a sign convention
    • 6.5.4 Additional guidance
  • 6.6 BS 7608 Fatigue of Welded Steel Joints
    • 6.6.1 Overview
    • 6.6.2 Derivation of the ,𝑺-𝒓.−𝑵 curve
    • 6.6.3 Analysis of axially loaded bolts
    • 6.6.4 Effect of the characteristic length
    • 6.6.5 Effect of stress relief
    • 6.6.6 Effect of small cycles
    • 6.6.7 Effect of large cycles
    • 6.6.8 Effect of exposure to sea water
    • 6.6.9 Failure mode
    • 6.6.10 Specifying the ,𝑺-𝒓.−𝑵 curve as a BS 7608 weld class
    • 6.6.11 Specifying the ,𝑺-𝒓.−𝑵 curve as user data
    • 6.6.12 Compatibility with other features
    • 6.6.13 Configuring the analysis parameters
  • 6.7 NASALIFE
    • 6.7.1 Overview
    • 6.7.2 Methodology
    • 6.7.3 The effective stress parameter
    • 6.7.4 Defining a NASALIFE analysis
    • 6.7.5 Guidance for load history gating
  • 6.8 Uniaxial Stress-Life
    • 6.8.1 Overview
    • 6.8.2 Defining a uniaxial stress-life analysis
  • 6.9 Uniaxial Strain-Life
    • 6.9.1 Overview
    • 6.9.2 Defining a uniaxial strain-life analysis
  • 6.10 User-defined algorithms
    • 6.10.1 Overview
    • 6.10.2 Variables passed in for information
    • 6.10.3 Variables to be defined
    • 6.10.4 Material properties
    • 6.10.5 Utility functions
    • 6.10.6 Additional stress histories
• 7. Mean stress corrections
  • 7.1 Background
  • 7.2 Goodman
  • 7.3 Soderberg
  • 7.4 Gerber
  • 7.5 Morrow
    • 7.5.1 Strain-life
    • 7.5.2 Stress-life
  • 7.6 Smith-Watson-Topper
    • 7.6.1 Strain-life
    • 7.6.2 Stress-life
  • 7.7 Walker
    • 7.7.1 Overview
    • 7.7.2 Walker 𝜸-parameter
    • 7.7.3 Strain-life
  • 7.8 R-ratio S-N curves
  • 7.9 User-defined mean stress corrections
• 8. Safety factor analysis
  • 8.1 Background
  • 8.2 Fatigue Reserve Factor
    • 8.2.1 Overview
    • 8.2.2 Included envelopes
    • 8.2.3 Specifying the target life
    • 8.2.4 Specifying the FRF limits
    • 8.2.5 Enabling FRF output
    • 8.2.6 User-defined FRF envelopes
    • 8.2.7 Treatment of residual stresses
  • 8.3 Factor of Strength
    • 8.3.1 Overview
    • 8.3.2 Enabling the FOS calculation
    • 8.3.3 Setting FOS band definitions
    • 8.3.4 Additional guidance on FOS parameters
    • 8.3.5 FOS augmentation
• 9. Job and environment files
• 10. Output
  • 10.1 Background
  • 10.2 Output variables
    • 10.2.1 Fatigue analysis field variable identifiers
    • 10.2.2 Static analysis field variable identifiers
    • 10.2.3 Fatigue analysis history variable identifiers
    • 10.2.4 Whole model variable identifiers
    • 10.2.5 MATLAB figure variable identifiers
  • 10.3 Viewing output
    • 10.3.1 Output location
    • 10.3.2 Changing the output format
    • 10.3.3 Limitations of critical plane output
  • 10.4 The ODB Interface
    • 10.4.1 Overview
    • 10.4.2 Accessing the ODB interface via the Export Tool
    • 10.4.3 Enabling the ODB interface via the environment file
    • 10.4.4 Configuring the ODB interface
    • 10.4.5 Mismatching ODB files
    • 10.4.6 Large ODB files
    • 10.4.7 Exporting field data to multiple Abaqus ODB part instances
    • 10.4.8 Minimum requirement for output
• 11. FEA Modelling techniques
  • 11.1 Background
  • 11.2 Preparing an FE model for fatigue analysis
• 12. Supplementary analysis procedures
  • 12.1 Background
  • 12.2 Yield criteria
    • 12.2.1 Overview
    • 12.2.2 Beltrami-Haigh isotropic total strain energy theory
    • 12.2.3 Shear strain energy theory
    • 12.2.4 Material properties
    • 12.2.5 Output
  • 12.3 Composite failure criteria
    • 12.3.1 Overview
    • 12.3.2 Conventions for fibre-reinforced composites
    • 12.3.3 Conventions for closed cell PVC foam
    • 12.3.4 Material properties
    • 12.3.5 Model definition
    • 12.3.6 Loading definition
    • 12.3.7 Maximum stress theory
    • 12.3.8 Tsai-Hill theory
    • 12.3.9 Tsai-Wu theory for fibre-reinforced composites
    • 12.3.10 Tsai-Wu theory for closed cell PVC foam
    • 12.3.11 Azzi-Tsai-Hill theory
    • 12.3.12 Maximum strain failure theory
    • 12.3.13 Hashin’s damage initiation criteria
    • 12.3.14 LaRC05 damage initiation criteria
    • 12.3.15 Output
    • 12.3.16 Example Usage
• 13. Tutorial A: Analysis of a welded plate with Abaqus
  • 13.1 Background
  • 13.2 Preparing the RPT file
  • 13.3 Running the analysis
  • 13.4 Post processing the results
• 14. Tutorial B: Complex loading of an exhaust manifold
  • 14.1 Background
  • 14.2 Preparation
  • 14.3 Defining the material
  • 14.4 Running the first analysis
  • 14.5 Viewing the results with Abaqus/Viewer
  • 14.6 Running the second analysis
  • 14.7 Post processing the results
• Appendix I. Fatigue analysis techniques
• Appendix II. Materials data generation
• Appendix III. Gauge fatigue toolbox
• References