Study on Crack Retardation with the Consideration of Crack Surface Roughness by FEM

Abstract

As one of the key factors to induce crack closure, crack surface roughness plays a dominated role in evaluating the characteristics of short fatigue cracks. The crack retardation induced by the crack surface roughness was investigated by numerical simulation in this paper. The influence of crack surface roughness on short fatigue cracks was directly applied into the numerical simulation procedure with the help of friction coefficients on the contacted crack surfaces. The driving forces of cracks represented by the two indicators such as crack tip displacement and plastic strain range were studied and used to characterize the retardation induced by crack surface roughness. It is shown that the evidence of crack surface roughness affecting on crack retardation is obvious and the influence of crack surface roughness on the characteristics of short fatigue cracks must account for in evaluating the performance of short fatigue cracks.