The Use of Elastic-Plastic Finite Element Analysis in the Calculation of Cumulative Fatigue Damage

A NASTRAN elastic-plastic finite element analysis of a notched fatigue specimen was performed and the results compared with experimental notch root strain. The calculated notch stress and strain were used in a cumulative damage procedure for determining specimen life which was compared to experimental fatigue life for three different loading spectrums for a Man-Ten steel material. The finite element analysis shows promise in replacing the full scale testing of prototypes now required to determine notch factors. Fatigue prediction from the drawing board could allow redesign of critical areas before expensive prototypes are built.