Prediction of the Ultimate Strength of Composite Laminates under in-Plane Loading Using a Probabilistic Approach

A numerical approach to predicting the ultimate strength of composite laminates is presented. In order to take into account the wide scatter in ply strengths, the basic strength distribution functions for the longitudinal, transverse and in-plane shear strengths were obtained using a two-parameter Weibull distribution. These functions, in conjunction with the Tsai-Hill failure criterion, were then used to predict the ultimate strength of the composites. Reasonable agreement was obtained between the predicted and experimental results, not only in respect of the ultimate strength, but also in relation to the stress-strain curves for the various composites.