Branch cracking and debonding at an end of a rigid stiffener under anti-plane shear stress

A semi-infinite body with a rigid stiffener on a part of the surface under uniform anti-plane shear stress is considered. This is a mixed boundary value problem, and a closed and exact solution is obtained. Stress concentration occurs at the ends of the stiffener; therefore a crack or a debonding may occur at the end of the stiffener. This paper investigates the competition between a crack or a debonding occurrence. It also investigates how far the debonding will extend. The maximum strain energy release rate is used as criterion for detecting a crack and a debonding initiation. Also the strain energy release rate just after crack initiation is investigated and the crack initiation angle is 140.8°. As the applied load, the following three kind of loading conditions are considered; constant loading, increasing loading and small cyclic loading.