Asymptotic analysis of cracks in the adhesive layer of an orthotropic sandwich structure

We analyze the asymptotic problems of an interface crack in an orthotropic sandwich structure and a semi-infinite subinterface crack in an orthotropic bimaterial. Stress intensity factors for the asymptotic problems are obtained from the path independence of the J integral; these involve only each undetermined dimensionless function. The dimensionless functions are shown to depend on three bimaterial parameters and two orthotropy parameters. By employing an orthotropy rescaling technique, the explicit dependence of one orthotropy parameter on the dimensionless functions is obtained. The effects of the other four material parameters on the dimensionless functions are numerically determined. The asymptotic problem of a crack in an adhesive layer of a sandwich structure is also considered. The stress intensity factors for the crack in an adhesive crack are obtained, with only one dimensionless function undetermined. An approximate formula for the dimensionless function is obtained in terms of the solutions of dimensionless functions for both the interface crack and the subinterface crack.