Experimental investigation of the path-independent fracture of composites

Abstract

Cohesive zone modelling is the main tool to solve the problems of crack initiation and growth, and therefore several mixed-mode cohesive laws are being developed. The majority of the cohesive laws are path independent because this property offers several advantages. However, there has been no experimental evidence of path-independent fracture. Within linear elastic fracture mechanics, path independence is a prerequisite, but not in problems with a large fracture process zone. In this study, it was demonstrated experimentally that path independence applies, to a certain degree, to unidirectional composites with large-scale fibre bridging. Thus, path-independent mixed-mode cohesive laws, preferably derived from a potential function, can be used to describe fracture for this class of materials.