A FRACTURE MECHANICS APPROACH TO HIGH-CYCLE FATIGUE CRACK GROWTH UNDER IN-PLANE BIAXIAL LOADS

Abstract

Abstract Fatigue crack growth under biaxial tensile load conditions is reported for a structural sheet steel. The new test facility can operate at high frequency (0–40 Hz) thereby permitting real-time testing required for threshold investigations; specimens are of the cruciform type. It is found that crack growth rate is affected by a cyclic tensile load applied in the direction of growth which decreases as the said load increases. The rate however increases if the biaxial loads are increasingly out of phase. Within the test conditions reported LEFM can be applied to crack growth under biaxial load conditions. The threshold stress intensity range is shown to be a function of load biaxiality, phase difference and stress ratio.