Stress Intensity Factor Analysis of Interface Crack using Boundary Element Method : Application of Virtual Crack Extension Method

Abstract

This paper presents a new method for stress intensity factor analysis of a two-dimensional interface crack between dissimilar materials. In the present paper, the virtual crack extension method which is a powerful tool for evaluating the stress intensity factor is combined with the boundary element method. A stress analysis is carried out using the boundary element method, and then virtual finite elements are assumed around a crack tip. The nodal displacements of these virtual finite elements are evaluated as internal points of a boundary element analysis. At first, we applied the present method to a center-cracked homogeneous plate under tension. Furthermore, we analyzed a bimaterial plate with a center interface crack and a bimaterial plate with a center slant interface crack subjected to tension. In such mixed mode problems, the M1-integral was applied to the mode-separation to obtain the individual mode stress intensity factors. It is found from these analyses that the present method gives very accurate results whose accuracy is insensitive to the size of virtual finite elements.