J041041 Prediction of Crack Growth Life by the Liner Cumulative Damage Rule Considering Effective Stress Range : Effect of Maximum Stress during Fatigue Tests

Abstract

A series of fatigue test was carried out under several two step loading waves varied a ratio of high load amplitude to low load amplitude by using a round bar specimen with small hole. The obtained fatigue life was compared with the predicted life by the liner cumulative damage rule from S-N curve that was obtained from the fatigue test under constant load amplitude. Moreover, effective stress ranges under two step loading wave and constant load amplitude were compared. These two comparisons were correlated. Therefore, it was proposed to predict the crack growth fatigue life from the liner cumulative damage rule considered the change of effective stress range due to load variance.