Application of the cubic strength criterion to the failure analysis of composite structures

摘要

A combined analytical and experimental investigation of the failure of composite laminates in a plane stress state is described. Strength predictions based on both the cubic and quadratic formulations are presented and the results compared to test data for both simple and complex biaxial loading. Multi-mode failure cases were also studied, including combined loading. In most instances it was demonstrated that the quadratic criterion does not provide accurate strength predictions and leads to overestimates for some configurations. Test data are included on the effect of prolonged thermal-vacuum cycling on the change in matrix stiffness and tensile strength. Results are presented for a graphite/epoxy prepreg which was subjected to over one year's exposure in a space simulator.