Interfacial Debonds in Unidirectional Fibre-Reinforced Composites Exposed to Biaxial Loads

One of the principal tasks in developing failure criteria in long-fibre reinforced material is to understand the fibre-matrix interface failure. In this work, the influence of the second transverse load on the interface crack onset is presented for two cases: a single fibre and a bundle of fibres. A non-classical approach of fracture mechanics is used to model the initiation of such a crack - a stress-driven weak solution approach for the Cohesive Zone Model, with various options for defined type of cohesiveness: bilinear, exponential Ortiz-Pandolfi, elastic-brittle. All obtained results predict that a secondary transverse compression decreases the critical value of the primary transverse tension which triggers debonding.