A delamination criterion for laminated composites under low-velocity impact

This paper describes details of an improved delamination criterion for laminated composite structures and its implementation to LS-DYNA3D. Out-of-plane stresses have been taken into consideration for damage initiation. The new delamination criterion, verified by experimental results for low-velocity impact, takes into consideration both the interlaminar shear and through-thickness compression stresses. Improved from the criterion proposed previously [Hou JP, Petrinic N, Ruiz C. Prediction of impact damage in composite plates. Composites Science and Technology 2000; 60(2): 273–81], delamination is not fully constrained by the out-of-plane compression. The influences of high local interlaminar shear stress induced by matrix cracking and fibre failure on delamination have also been taken into account. Predicted results from different criteria have been discussed, in comparison with experiment work.