Numerical simulations of a dynamically propagating crack with a nonlinear cohesive zone

Numerical solutions of a dynamic crack propagation problem are presented. S pecifically, a mode III semi-infinite crack is assumed to be moving in an u nbounded homogeneous linear elastic continuum while the crack tip consists of a nonlinear cohesive (or failure) zone. The numerical results are obtain ed via a novel semianalytical technique based on complex variables and inte gral transforms. The relation between the properties of the failure zone an d the resulting crack growth regime are investigated for several rate indep endent as well as rate dependent cohesive zone models. Based on obtained re sults, an hypothesis is formulated to explain the origin of the crack tip v elocity periodic fluctuations that have been detected in recent dynamic cra ck propagation experiments.