Asymmetric crack onset at open-holes under tensile and in-plane bending loading

Plates notched with open-holes that are subject to combined tensile and in-plane bending loading are studied in this analysis of crack onset. A finite fracture mechanics approach is employed to study the onset of asymmetric crack patterns in the notched structure. The stress field and the energy release rates required to solve the coupled stress and energy criterion are obtained from linear elastic finite element analyses. Closed-form expressions for the dependence of the solution on governing parameters as e.g. the structural size, the Young's modulus or the ratio of bending to normal loading are given significantly reducing the computational effort required for the failure model. A comparison to experimental results and to numerical analyses using a cohesive zone model highlights the model's ability to render brittle failure of the notched structure and to provide reliable failure load estimates. The results reveal that a certain threshold of the hole diameter exists, below which the hole does not affect the failure load. The threshold and the corresponding bearable loads are discussed using explicit solutions.