Mode II and mode III stress singularities and intensities at a crack tip terminating on a transversely isotropic-orthotropic bimaterial interface

Abstract

In a recent paper (referred to as I) we obtained inter alia , the stress and displacement fields at the tips of a transverse crack in an isotropic medium sandwiched between orthotropic media under in-plane loading (mode II). The crack was lying wholly within the isotropic medium so that the singularity at the crack tip was of the usual inverse square root type. In this paper, the analysis is extended to the case when the tip of the crack terminates on the transversely isotropic-orthotropic bimaterial interface and the nature of the singularity at the crack tip depends on the elastic properties of both media. The analysis is performed for both inplane (mode II) and out-of-plane (mode III) shear loading. General solutions are obtained for the crack tip stress singularities and corresponding stress intensity factors, together with the influence of the elastic properties and geometry of the media upon the stress field. These solutions are specialized to the limiting case when the crack terminates on the interface between dissimilar isotropic media in order to demonstrate consistency with published results. As in I, the solutions are used to investigate the influence of ply angle θ upon the stress singularities in [± θ /90°] s fibre-reinforced composite laminates. For this analysis, the outer angle-ply sublaminates are treated macroscopically as homogeneous orthotropic media whose elastic constants are obtained using the classical lamination approximation. Calculations are also carried out to study the variation of stress intensity factors with the ply angle and outer sublaminate thickness.