5.1. How Fatigue Is Calculated

The fatigue calculations rely on the ASME Boiler and Pressure Vessel Code, Section III (and Section VIII, Division 2) for guidelines on range counting, simplified elastic-plastic adaptations, and cumulative fatigue summation by Miner's rule.

For fatigue evaluations based on criteria other than those of the ASME Code, you can either write your own macro, or else interface your results with an appropriate third-party program.

The program features the following fatigue-calculation capabilities:

  • Postprocessing existing stress results to determine the fatigue usage factors for any solid-element or shell-element model. (You can also manually input stresses for fatigue evaluation of line-element models.)

  • Storing stresses at a preselected number of locations for a preselected number of events and loadings within the event.

  • Defining stress concentration factors for each location and scale factors for each event.