Mixed-mode steady-state crack growth in elastic-plastic solids

Abstract

In this paper, steady, quasi-static crack growth under plane strain conditions in an elastic-plastic material subjected to mixed-mode loading (combined mode I and mode II) is analyzed. A modified small scale yielding formulation ( Journal of the Mechanics and Physics of Solids, 1993, 41, 835–861) wherein the elastic K-field as well as the T-stress are prescribed as remote boundary conditions is used. A special finite element procedure based on moving crack tip coordinates is employed to simulate steady-state crack growth in the direction ahead of the tip. The material is assumed to obey the J 2 flow theory of plasticity, with a power-law hardening stress-strain response. The results show that the near-tip mode-mixity is dependent on the level of strain hardening, magnitude and sign of the T-stress and on the remote elastic mixity. The influence of the above parameters on the near-tip stress and deformation fields is examined and the range of remote elastic mixity that gives rise to a mode I or mode II distribution is identified.