Effect of interfacial zone on mechanical behavior and failure of fiber-reinforced composites

Abstract The mechanical behavior of the interphase between fibers and matrix is modeled by continuity of tractions, and a linear relation between displacement differences across the interphase and the conjugate tractions. The proportionality constants characterize the stiffness and the strength of the interphase. By the use of this model, and for transverse loading of a rectangular-array fiber-reinforced composite, numerical results have been obtained for the stresses in the matrix and in the fibers. Variation of the interphase parameters causes pronounced changes in these stress distributions. The initiation, propagation and arrest of interphase cracks have been analysed based on a criterion of critical strain energy density in the interphase. The results have also been used to display the effect of the interphase parameters on the overall elastic moduli of the composite, prior as well as subsequent to the development of interphase cracks.