Experimental and Computational Studies on Fatigue Crack Propagation under the Effects of Random Sequence of Clustered Loading

摘要

Fatigue crack propagation under the effects of random sequence of clustered loading is investigated in the present paper, where we use the so-called "storm model". Fatigue crack propagation is simulated based on the stress intensity range corresponding to the repeated tensile plastic deformation at the crack tip. These methods are successfully incorporated into the crack propagation simulation code, CP-system, which can predict crack paths and the corresponding stress intensity factors based on step-by-step finite-element analyses. Fatigue crack growth is investigated by numerical simulation and fatigue tests for various random sequences of clustered loading. The experimental and numerical results show very good agreement with each other, where they are considerably retarded under random sequence loading, so that the conventional equivalent stress approach may give relatively conservative results to the real seaway loading.