The paper deals with crack propagation through an interface between two elastic materials. The basic idea of developing stability criteria of general singular stress concentrators introduced in the first part is applied to the case of a crack with its tip at the interface between two different materials. Three different stability criteria based on different physical principles are presented and a numerical example with their mutual comparison is carried out. A procedure based on a generalized strain energy density factor is shown which makes it possible to estimate the further direction of crack propagation after the crack has passed the interface. The procedure presented is applied in the numerical examples. and Obsahuje seznam literatury
Crack propagation in anisotropic materials is a persistent problem. A general concept to predict crack growth is the energy principle: A crack can only grow, if energy is released. We study the change of potential energy caused by a propagating crack in a fully three-dimensional solid consisting of an anisotropic material. Based on methods of asymptotic analysis (method of matched asymptotic expansions) we give a formula for the decrease in potential energy if a smooth inner crack grows along a small crack extension.