Influence of crack front shape on 3D numerical modelling of plasticity-induced closure of short and long fatigue cracks

摘要

The simultaneous effect of crack length and crack front shape on plasticity-induced crack closure (PICC) for a 304L austenitic stainless steel is simulated through 3D numerical modelling using finite element software Abaqus for through-thickness cracks with different curved crack fronts in CT specimens in comparison with bidimensional through crack with a straight front. The influence of possible loading history effect is avoided by applying constant AK amplitude. The local stress intensity factor range for crack opening K_(op) is evaluated from the simulation of the loss of the last local contact between the crack lips near the crack tip. The pertinence of the different crack front shapes is discussed in term of the effective stress intensity factor range ΔK_(eff) and in comparison with the experimental crack front observations.