Cumulative Damage Models and Multi-Stress Fatigue Life Prediction

Abstract

Cumulative damage during fatigue is studied analytically. Extensive reviews are per formed on the published damage models. Three different cumulative damage models are defined using several physical variables such as fatigue modulus and resultant strain. Proposed model I is defined using fatigue modulus, while models II and III are defined using resultant strains. Proposed models are derived as functions of nor malized applied stress level, r, and number of fatigue cycle, n. It is verified that the proposed cumulative damage model III has better agreement with the two stress level fatigue experimental data than other models.