A delamination criterions for laminated composites under low-velocity impact

This paper describes details of an improved delamination criterion for lami nated composite structures and its implementation to LS-DYNA3D. Out-of-plan e stresses have been taken into consideration for damage initiation. The ne w delamination criterion, verified by experimental results for low-velocity impact, takes into consideration both the interlaminar shear and through-t hickness compression stresses. Improved from the criterion proposed previou sly [Hou JP, Petrinic N, Ruiz C. Prediction of impact damage in composite p lates. Composites Science and Technology 2000; 60(2): 273-81], delamination is not fully constrained by the out-of-plane compression. The influences o f high local interlaminar shear stress induced by matrix cracking and fibre failure on delamination have also been taken into account. Predicted resul ts from different criteria have been discussed, in comparison with experime nt work. (C) 2001 Elsevier Science Ltd. All rights reserved.