Dislocation Arrays and Elastic-Plastic Cracks in a Two-Phase System

Abstract

A dislocation model is used to study the propagation of elastic- plastic shear cracks in composite materials. It is found that the ex tension of plastic zones in ductile matrices is governed by both the yield strength and rigidity of the matrix phase. Knowing the length of plastic zone, the crack opening displacement can be found. For a constant length of plastic zone, the crack opening displacement in creases as the rigidity of the matrix material decreases. Suppose the fracture of the two-phase system under consideration is caused by reaching a critical crack opening displacement at the crack tip, the critical fracture strength can be determined from the knowledge of fracture toughness of the matrix material.

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