Midas FEA fatigue analysis estimates fatigue damage and life from stress histories, using stress-life S-N data, rainflow counting, mean stress treatment, modification factors, and Miner linear damage accumulation.
How It Works
The manual presents fatigue as a post-analysis workflow built from elastic stress results. Nodal stresses are derived from stress measures such as von Mises or maximum principal stress, stress amplitude histories are constructed, and S-N data are used to estimate damage and life.
The procedure accounts for mean stress, stress concentration, surface finish, load type, size or shape factors, temperature, environment, rainflow cycle counting, and linear cumulative damage. Outputs include fatigue life and safety-factor style quantities at nodes.
Solver Development Notes
Treat fatigue as a results-processing feature unless material degradation is explicitly coupled back into the solve.
Keep the stress measure, location, interpolation, and scaling rules fixed for regression tests.
Use small hand-checkable stress histories to verify rainflow counting and Miner summation before using full FE histories.
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