Nonlinear temperature dependent failure analysis of finite width composite laminates

A quasi-three dimensional, nonlinear elastic finite element stress analysis of finite width composite laminates including curing stresses is presented.

Cross-ply, angle-ply, and some quasi-isotropic graphite/epoxy, laminates are studied. Curing stresses are calculated using temperature dependent elastic properties that are input as percent retention curves, and stresses due to mechanical loading in the form of an axial strain are calculated using tangent modulus, obtained by Ramberg Osgood parameters.

It is shown that curing stresses are significant only as edge effects in angle-ply laminates, and severe throughout the laminate in cross-ply laminates. The tensor polynomial failure, criterion is used to predict the initiation of failure, and the failure mode is predicted by examining individual contributions of the stresses to the polynomial.