Ply Bunching and Delamination Effects on the Open-Hole Tensile Strength of Laminated Composites

摘要

Open-hole tension (OHT) testing of laminated composites is commonly performed to generate data for designing composite structures because it is often used as a limiting design criterion for damage tolerant structures. Despite extensive studies, the open-hole tensile strength and the associated failure mechanisms have yet to be fully understood, and the general prediction of OHT strength is still difficult and inaccurate. In this study, a finite element based progressive damage tool is developed for predicting the OHT strength of laminated composites, with proper accounting of ply bunching and possible delamination dominated failure. Simulation results are compared to a set of OHT test data performed on (CFRP) laminates with a variety of laminate stacking sequences and ply bunching. The results show that in cases where the increased toughness due to ply bunching and delamination dominated failure is significant, the finite element model must include the underlying physics if accurate prediction of OHT strength is to be achieved.