Stress analysis of a crack in a fiber-reinforced layered composite

Brittle matrix composites such as fiber-reinforced cements and ceramics are often bonded to dissimilar materials such as metals or other ceramics. The mismatch in elastic properties can affect the growth of matrix cracks located near the bonded interface. In this paper, a bonded system comprising of an elastic layer sandwiched between two identical elastic half-spaces is considered. A mathematical model is developed based on the distributed dislocation technique, for the analysis of a bridged straight crack embedded in the elastic layer. The bridging tractions are considered to be dependent on the crack opening displacement. The stress field is assumed to be plane stress or plane strain and all three-dimensional effects are disregarded. The numerical results include the critical stress required to initiate failure of the matrix and the failure of fibers bridging the crack. The dependencies of these critical values upon the thickness of the composite layer as well as the mismatch in elastic properties are presented in dimensionless form. The results can be used to estimate the residual strength of bonded composites with a flaw near the material interface. (C) 2014 Elsevier Ltd. All rights reserved.