Spectrum Fatigue Life Predictions for Typical Automotive Load Histories and Materials Using the Sequence Accountable Fatigue Analysis

In the course of the SAE Cumulative Fatigue Damage Test Program coupons of two steel materials were tested under three different loading histories typical of those seen at different locations in an automotive structure. Variations in the materials, spectra and loading severity caused the resulting fatigue crack initiation lives to range from the very low-cycle to the very high-cycle fatigue regime. This paper documents the procedure used in applying the Sequence Accountable Fatigue analysis to make crack initiation life predictions for the applied spectrum loading conditions. These predictions compare favorably with the measured data for both materials under the variety of loading spectra and severities seen in the SAE program.