A simple transverse damage model for unidirectional composites

A simple transverse damage model for unidirectional composites was established, in the case when the composite specimen is loaded transversely. The model ignoring thermal stress, based on Griffith's virtual work argument and usual damage theories, gives a crack propagation criterion at the fiber/matrix interface. By extrapolation to the case of null crack length, the transverse tensile strength was found to depend directly on the crack opening angle at the interface and then on the interface surface energy. In situ transverse tensile tests were carried out on a unidirectional E-glass fibers/epoxy composite. The combination of the developed model with the experimental results gave the interface surface energy.