Theoretical and experimental studies on the extension of cracks subjected to concentrated loading near their faces to compare the criteria for mixed mode brittle fracture

Abstract

The criteria of maximum tangential stress (MTS), maximum tangential principal stress (MTPS), maximum tangential strain (MTSN) and strain energy density (SED) are applied to problems of infinite sheets with straight cracks loaded at or very near their faces by in-plane point loads. Prediction of the direction of initial crack extension, critical load and unstable crack path are made. Unlike the results reported earlier by various investigators predictions by the four criteria differ substantially. The accuracy in respect of prediction of crack path is checked experimentally for a particular loading. The results indicate that a modification of the definition of the criteria of MTSN and SED is beneficial.