Boundary Element Analysis Of Interface Cracks InDissimilar Orthotropic Materials Using A PathIndependent Contour Integral

Abstract

This paper presents a boundary element method for analysis of interface cracks in dissimilar materials. A path independent contour integral is used to obtain the complex stress intensity factors. For mixed-mode problems the crack opening displacements are used to decouple the stress intensity factors. The proposed technique is applied to interface cracks in both isotropic and orthotropic dissimilar materials. Several examples are presented to demonstrate the accuracy of the method. The problem of cracks along the interface of orthotropic dissimilar materials has an important role in the structural analysis due to the extensive use of composites and reinforced materials in the modern industry. The strength of bonded joints between composite materials can be assessed through the knowledge of stress intensity factors of cracks located at the material's interface. In the study of interface cracks, Williams}!), Erdogan[2] and Rice[3] describe the characteristic oscillating behaviour of stresses and displacements near the crack tip in dissimilar isotropic materials. Rice[3] used the Muskelishvili's complex function theory and defined the complex stress intensity factor associated with an elastic interface crack, ignoring the possible contact zone due to the oscillation of displacements. Some discussions are also presented in this work related to the validity of the complex stress intensity factor as a crack tip characterizing parameter.