Theoretical Modelling of the Effect of the Interfacial Shear Strength on the Longitudinal Tensile Strength of Unidirectional Composites

Abstract

An approach coupling Rosen's cumulative damage model [1,2] and Piggott's elastic-slip stress transfer model [3,4] is presented here, to demonstrate the effect of the interfacial shear strength on the longitudinal tensile strength of unidirectional fiber-reinforced polymer composites. It was found numerically that an interface strong in shear would in crease the longitudinal tensile strength of the composite marginally. According to the ap proach developed, in the situations where the fiber strengths scattered markedly, or where the coefficient of friction between debonded fibers and matrix is very small, an increase in the interfacial shear strength would enhance the longitudinal tensile strength in a relatively significant manner. Additionally, an interface layer was introduced in Piggott's elastic-slip stress transfer model, so as to render the model conceptually more nearly cor rect.