Performing Fatigue Analysis

To perform fatigue analysis:

  1. Create one or more static, nonlinear or modal time history dynamic studies.
  2. Create a fatigue study (constant amplitude or variable amplitude) and define its properties. Make sure to set the proper options before running the study.
  3. Notice the events type shown with the name of the Loading folder in the Simulation study tree. Right-click the Loading folder and select Add Event to define a fatigue event based on a reference static study, or on a particular solution step from a nonlinear or modal time history dynamic study. To define a fatigue event based on multiple reference studies, set Loading Type to Find Cycle Peaks.
    Variable amplitude events usually contain large amount of data. The Function Curve dialog lets you import text files containing the data as load history curves. The data become available when defining a variable amplitude fatigue event.
  4. You must define at least one SN curve for each material. Click the Fatigue SN Curves tab in the Material dialog box to define SN curves.
  5. Right-click Result options and select Define/Edit to request results at all nodes or at boundary nodes only. If the study is based on variable amplitude events, you can request the Rainflow matrix chart at the desired locations.
  6. For variable-amplitude fatigue studies, right-click a fatigue event icon and select Plot 3D Rainflow matrix or Plot 2D rainflow matrix to plot a chart for the bins of the input load history
  7. Run the fatigue study.
    If the results of a reference study, used in defining an event, are not available, the program runs the reference study automatically before running the fatigue study.
  8. Set the fatigue study analysis options. Right-click the topic icon and click Properties. See help topic Fatigue Analysis Options for more information on the fatigue options.
  9. View results:
    • Double-click an icon in a results folder to display the associated plot.
    • To define a plot, right-click the Results folder and select the Define Fatigue Plot.
    • To list results, right-click the Results folder and select List Fatigue Results.
    • For studies with variable amplitude events, right-click the Results folder and select Define Matrix Charts to view Matrix Charts.
    Click here for more result viewing options.
    If you run a study before meshing it, the program meshes the study automatically before running it. You can also request to run the study by checking Run analysis after meshing in the Mesh PropertyManager.
    When you run a study that does not have any result folders, the software creates the folders and plots specified in the Result Options for the study type. If result folders are present, the software updates the existing plots.