Create an FKM Analysis Case and Define the Fatigue Assessment

Create an FKM analysis case to be used for the fatigue assessment. The FKM analysis case contains the fatigue assessment based on the stresses calculated in the structural analysis case.

This task shows you how to:

Create an FKM Analysis Case

  1. From the standard area of the action bar, click Scenario .
  2. From the Durability section of the action bar, click Create FKM Case .
  3. Accept the default name for the FKM analysis case, and click OK.
    The context selector switches to the FKM analysis case.

Define the FKM Fatigue Assessment

  1. From the Durability section of the action bar, click FKM Fatigue Assessment.
  2. Accept the default values in the FKM Fatigue Assessment dialog box, and click OK.
  3. From the Durability section of the action bar, click Weld Fillet Set .
  4. Select the fillets that represent the welds, as shown below.

    The weld fillet sets appear in the tree under the Interactions node of the FKM analysis case.
  5. From the Durability section of the action bar, click Fatigue Loading .
  6. Click Superposition .

    In this type of fatigue loading event, the app superimposes all the loads and signals rather than organizing the events in series.

    A superposition event appears in the fatigue loading history.
  7. Double-click the Repeats row under the superposition event, and change the value to 12,000.

    This value represents the number of loading events that the fatigue calculation evaluates.

  8. Right-click the superposition event, and select Add frame.

    Frames specify which stress results to include in a superposition event.

  9. From the Frames dialog box, select the Left load case and click OK.
  10. Right-click the frame, select Add signal values, and enter 1, 0.

    The 1, 0 values create a "pulse" signal where the stress alternates between on (1) and off (0).

  11. Similarly, add superposition events for the Mid and Right load cases.
  12. Click OK.