Initiation, Propagation, and Kinking of an In-Plane Crack

Abstract

Consider an infinite linear elastic body containing a semi-infinite crack loaded by a longitudinal stress pulse parallel to the crack face. After the stress wave strikes the crack at time t = 0, the stress gradually intensifies at the crack tip. At some finite delay time tt , the crack begins to extend straight ahead with constant speed vo . At some later time tb , the crack suddenly stops, then kinks and propagates with constant speed vc , making an angle δ with the original crack. The exact full field solution of the propagating crack is constructed by using a superposition of fundamental solutions for a particular class of problems. When the crack suddenly stops, the stress field for a stationary crack with the new crack length is radiated out from the stopped crack tip. The dynamic stress intensity factor at the kinked crack tip can then be obtained by using a perturbation method.