Elastic-Plastic Analysis of Cracks on Bimaterial Interfaces. Part 1. Small Scale Yielding

摘要

Full field numerical solutions for a crack which lies along the interface of an elastic-plastic medium and rigid substrate are presented. The solutions are obtained using a small strain version of the j2 deformation theory with power law strain hardening. In the present article result for loading causing only small scale yielding and fully plastic behavior will be presented. The oscillatory stresses on the bond line and overlapping of the crack faces, characteristic of small strain linear elasticity, are shown to be essentially precluded by material nonlinearity. In addition we find that, although the near tip fields do not appear to have a separable form as for the well known HRR fields in homogeneous media, they do bear interesting similarities to certain mixed mode HRR fields. Numerical procedures appropriate for solving a general class of interface crack problems are described. A description of a numerical method for extracting the mixed mode stress intensities for cracks at interfaces, and in homogeneous isotropic or anisotropic media, is included.