Load interaction effect on fatigue crack growth in through-wall cracked pipes under large scale yielding: Experimental and numerical investigation

Abstract

ABSTR A C T In this paper, the load interaction effect on fatigue crack growth under large scale yielding conditions is investigated, via combined experimental and finite element (FE) analyzes of a through-wall cracked pipe. For the fatigue load amplitude, two amplitudes were applied to the through-wall pipe, 75% and 85% of the experimental maximum load under monotonic loading. For the loading type, periodic overload, high-low and low-high loading sequences were applied. It is experimentally found that the change of crack growth rate due to load interaction does not occur under large scale yielding, in contrast to the behavior under small scale yielding. Numerical analysis using FE debond analysis further shows that crack closure does not occur in the through-wall cracked pipe under large scale yielding fatigue loading, which can explain no load interaction effect on fatigue crack growth, observed in the present experiment.