Interlaminar Fracture Behavior and Fiber Bridging of Glass-Epoxy Composite Under Mode I Static and Cyclic Loadings

Abstract

Interlaminar fracture behavior of composite materials under static and cyclic loadings has been studied using a width tapered double cantilever beam specimen. The fracture energy is evaluated by compliance, beam and area methods. The comparison results show that the initial fracture energy could be evaluated either by beam or area method while the crack growth resistance could be calculated by compliance method. Increases in the criti cal load and fracture energy due to fiber bridging are predicted by a power function of fracture area. The interlaminar fatigue crack growth behavior is studied through the con stant cyclic strain energy release rate range test. A modification of Paris' power law is made to interpret fatigue crack growth under the influence of fiber bridging. The predicted fatigue life by the modified power law is reasonably close to the experimental data. Frac tography study shows that the interlaminar failure mechanism of a composite beam in volves fiber breakage, matrix tearing and transverse microcracking as well as the delamination of the layers.