Fatigue Crack Growth in Mixed Mode Loading

Abstract

In this paper, a direct approach based on the mixed mode Dugdale model, the accumulated plastic displacement criterion for crack propagation and the cyclic J-integral concept is used to develop equations to predict the mixed mode fatigue crack growth. A fourth-power stress intensity factor crack growth equation and a second-power cyclic J-integral equation are developed under conditions of mixed mode loading and small-scale yielding. By comparing the present analysis with the experimental results, the proposed fatigue crack growth rate equations lead to results that appear to yield reasonable magnitudes for various loading conditions.