Stress Intensity Factors for Rough Cracks Loaded in Mode II

Abstract

Most fracture mechanical models do not take the materials microstructure into account and use averaged material properties although the real crack flanks and fronts exhibit microstructurally induced tortuous shapes. These influences the stress-strain field at the crack front as well as the related stress intensity factors. This phenomenon was investigated by some authors only for remote mode I loading and was named geometrically induced shielding. This study is focused on the analysis of the stress intensity factors for rough cracks loaded in the shear mode II by modelling the Compact-Tension-Shear (CTS) specimen containing cracks of various roughness. The study revealed that, in accordance with our previous study, already small changes in the crack roughness have a rather high influence on the local field of stress intensity factors. The local stress intensity factor KII decreases with increasing roughness and, for its higher levels, it converges to a constant value that is significantly lower than that of the remote mode II loading associated with the planar crack of the same length.