Distributions of SIFs for symmetrical part-elliptical and semi-elliptical surface cracks in plates subjected to crack face shear loading

Abstract

The distributions of SIF s K II, K III and their ratios along crack fronts of symmetrical part-elliptical (PE) surface cracks with a critical inclination angle β c in plates subjected to uniform crack face shear loading were evaluated using three-dimensional FEM. The results are then compared with the corresponding results obtained for semi-elliptical (SE) surface cracks. The differences between PE and SE cracks in distributions of K II, K III are small at positions where ϕ/ ϕ c ⩽0.625, but are appreciable at positions where ϕ/ ϕc >0.625. The distribution of the K II/ K III ratio is mainly dependent on the crack aspect ratio a/ c and the crack front inclination angle β. The ratios K II/ K III at the corner points of the PE cracks with β = 66.8° and ν = 0.3 vary from 2.06 to 2.21 for geometries in this study. However for SE cracks they vary from 19 to 35. The PE cracks are very different from the SE cracks.