Abstract
Interlaminar toughness which is generally treated as a material constant is used as a quantity to express strength or toughness of the interlaminar region of composite laminates. As discussed by many researchers, the fracture toughness of the material depends on the fracture modes or process, that is, on the mechanism of the failure. So, the interlaminar toughness of composite laminates may depend on the inclination of the delamination propagating direction to the fiber even in the same mode fracture, because the micromechanical failure process at the delamination front may differ due to the differences of the micro-mechanical structures and the stress distributions at the neighborhood of the delamination front. In the present paper, mode I fracture toughnesses GIC of a carbon fiber woven composite are measured about various inclinations of delamination propagations to the fiber direction and its dependence on the inclination angle are investigated.
