The fracture analysis of composites by a micromechanical approach

Abstract

An analytical method developed for the analysis of fracture development in composites is described and illustrated for several composite systems. A classical fracture-mechanics modeling technique was employed with the process-zone concept and small- or large-scale analysis. The distinctive characteristic of the method described is an explicit consideration in the analysis of the discrete distribution of the reinforcing components within the composite. The reinforcement mechanisms in composites are based on formation of a system of restrictive forces imposed on the crack surfaces by reinforcing components. The region where these restrictive forces are activated, the so-called fracture process zone, is a subject of the analysis and model development for evaluating composite fracture resistance and strength. Representing the process zone geometry as a line zone allows one to obtain analytical solutions to the representative problems and to investigate detailed micromechanical aspects of the process. The methodology developed was applied to composites formed from a brittle matrix reinforced by unidirectional fibers and to a brittle matrix reinforced by ductile particles.