Discrete dislocation simulations of the development of a continuum plastic zone ahead of a stationary Mode Ⅲ crack

摘要

We present results from discrete dislocation simulations showing the development of the plastic zone in front of a Mode III crack under constant load. We find that the equilibrated zone is circular, in agreement with continuum mechanics predictions of the elastic-perfectly plastic Mode Ⅲ crack. The size of the equilibrated zone scales as the square of the applied load (K_(Ⅲ)), also in agreement with the continuum results. The zone approaches saturation exponentially, with a time that scales as K_(Ⅲ)~2/σ_p~3, where σ_p is the Peierls stress. These results delineate conditions under which the classical, continuum predictions of elastic-plastic fracture mechanics are applicable.