A Finite Element and Cumulative Damage Analysis of a Keyhole Test Specimen

The Cumulative Damage Division of the SAE Fatigue Design and Evaluation Committee recently finished an extensive fatigue test program. This test program involved one Keyhole test specimen, two different materials, three loading spectrums and the cooperation of eight test laboratories to run the 58 specific fatigue tests. The objective of the overall division program was to determine the state-of-the-art of cumulative damage life prediction capability using the experimental data for correlation.

This work reports a finite element and damage analysis of the Keyhole test specimen. The calculated notch root strain was compared with the experimental strain. The calculated stress and strain were used in a cumulative damage procedure to predict life for both materials subjected to various load levels for each of three loading spectrums. The results of the theoretical life predictions are compared to the experimental results.