Predicting the nonlinear response and progressive failure of composite laminates under triaxial loading: Correlation with experimental results

Abstract

This article represents our contribution to Part B of the 2nd Worldwide Failure Exercise (WWFE-II), where comparisons between epoxy/lamina/laminate response and failure predictions, based on maximum strain failure criterion, and experimental results are made. Correlations between actual test data and our nonlinear stress-strain response and failure envelope predictions under multi-axial loading for 12 different case studies are presented and discussed. Although our approach to modeling composite failure ranked high when applied to biaxial in-plane loading analysis, the theory does not consistently capture the inherent strengthening mechanisms that can be attributed to triaxial loading and hydrostatic pressure. It is expected that the incorporation of a strain-based ply-level failure criterion that introduces some form of strengthening mechanism under a three-dimensional stress state would significantly improve the accuracy of our predictions.