Determination of GIC in Angle Ply Composites Using a Cantilever Beam Test Method

A double cantilever beam test is used to measure G IC values in angle ply composites. It is demonstrated that the G IC values determined with this method are independent of the compliance of the specimen. In the angle ply composites, four different crack mor phologies are observed, each with different G IC values associated with crack growth. One morphology only appears in unidirectional laminates. A second appears as the crack front breaks through a ply. A third morphology appears as the crack grows be tween dissimilarly oriented plies neither of which is parallel to the direction of crack propagation. The fourth and final morphology appears as the crack propagates be tween two dissimilarly oriented plies one of which is oriented parallel to the direction of crack propagation.