A Fracture Mechanics Approach to the Analysis of Graphite/Epoxy Laminated Precracked Tension Panels

A methodology for the prediction of fracture in fiber composite laminates under monotonically increasing load is presented. In the model, laminate behavior is based on damage growth in individual plies with a fracture mechanics approach being used to continually assess the damage in each ply. Within each ply, damage may occur by crack extension parallel to or perpendicular to the fiber orientation in the ply. Critical values of strain energy release rate for both modes of damage are inferred from experimental data on center-cracked, zero-degree unidirectional laminates. At present, interply interactions are neglected. Despite this severe oversimplification, a comparison of strength predictions from the laminate model shows reasonable agreement with experimental results, both quantitatively and qualitatively, for [0/90]_4s, [±45]_4s, and [0/±45/0]_2s graphite/epoxy laminates. The features of the laminate model are contrasted with the models of a number of other researchers.