A Nonlinear Analysis of an Equilibrium Craze: Part II—Simulations of Craze and Crack Growth

Abstract

In this study we investigate the effects of nonlinear fibril behavior on the mechanics of craze and crack growth. The effect of strain-softening cohesive material on crack stability is of particular interest and is examined via a craze and crack model developed in the first part of this work where the formulation and solution of the problem are discussed.1 In this second part, quasi-static growth of a craze with a central crack is analyzed for different nonlinear force-displacement (p-v) relations for the craze fibrils. A “critical crack tip opening displacement” (CTOD), or more precisely, “critical fibril extension” is employed as the criterion for fracture. The p-v relation is further assumed to be invariant with respect to the craze and crack lengths. The results are compared with the Dugdale model; the craze zone size and the energy dissipation rate approach asymptotic values in the limit of long cracks. The problem of craze growth from a precut crack under increasing far-field loading is then studied. In the case where the p-v relation is monotonically softening, the crack can start to grow in an unstable manner before the crack tip opening displacement reaches its critical value.