Methods for calculating stress intensity factors for interfacial cracks between two orthotropic solids

Stress intensity factors for interfacial cracks between two dissimilar orthotropic materials were considered. Due to the oscillatory characteristics of stresses and displacements near the crack tip, individual strain energy release rates no longer exist. Instead, the individual strain energy release rates corresponding to a finite crack extension were obtained in terms of the stress intensity factors and the assumed crack extension Aa. The finite element methods in conjunction with the crack closure technique were used to calculate these finite extension strain energy release rates from which accurate stress intensity factors were obtained. An alternative method based on crack surface displacement ratio was also discussed. Non-oscillatory (Aa-independent) Mode I and Mode I1 "ʹstrain energy release rates" were also proposed to provide an alternate measure of fracture mode mixity or to be used as a fracture criterion for interracial cracks. ,~"~ 1998 Elsevier Science Ltd. All rights reserved.