AN ELASTOPLASTIC ANALYSIS OF THE INTERFACE CRACK WITH CONTACT ZONES

AN ELASTOPLASTIC solution for the interface crack with contact zones is presented in this paper. The elastic asymptotic solution is discussed first and approximate expressions for the Comninous stress intensity factors of a Griffith interface crack are obtained. It is shown that the elastic asymptotic solutions based on the assumption of a closed crack tip predict material interpenetration: material elements near the crack tip are "turned inside out" and cross the bimaterial interface. The problem of a crack along the interface of an elastoplastic material and a rigid substrate is analyzed in detail. Any contact between the crack surface and the substrate is assumed to be frictionless. An elastoplastic asymptotic solution for a closed crack tip under plane strain conditions is presented. It is shown that the asymptotic solution is separable in r and theta, where (r, theta) are polar coordinates at the crack tip. A boundary layer approach is used to study the near tip elastoplastic fields under small-scale yielding conditions. The finite element method is used for the solution of the small-scale yielding problem and the validity of the developed plastic asymptotic solution is verified numerically. Large-scale yielding solutions for a Griffith interface crack with contact zones are also presented.