Comparison between cohesive zone and coupled criterion modeling of crack initiation in rhombus hole specimens under quasi-static compression

Abstract

Numerical predictions of initiation loading and crack length in a rhombus hole specimen made of a brittle material under quasi-static compression using either cohesive zone model or coupled criterion based on finite fracture mechanics are compared. Both methods lead to the conclusion that crack initiation results in a crack jump over a finite length at a given loading level, which depends on the material parameters and on the specimen geometry. The initiation load level and crack extent depend on the cohesive zone traction-opening displacement profile which represents the underlying failure mechanism. The ranges of initiation force and crack lengths obtained with various traction-opening profiles respectively comprise the initiation force and lower bound for crack arrest derived from the coupled criterion. For the configuration under investigation, similar initiation forces and crack arrest lengths as those predicted using the coupled criterion are obtained using a bilinear cohesive zone model.