A coupled strength and toughness criterion for the prediction of the open hole tensile strength of a composite plate

The strength of an open holed composite plate subjected to tensile loading is analysed with the help of a coupled strength and energy criterion. Analytical and numerical models are used to determine the stress distribution and the energy released by crack nucleation in the vicinity of the hole. It is shown that the hole size effect can be described and that the crack length at nucleation both depends on the local geometry and the fracture characteristics of the specimen. These characteristic values can be identified with the help of traction tests performed on unnotched and holed samples.