Low-velocity impact predictions of composite laminates using a continuum shell based modeling approach Part b: BVID impact and compression after impact

In this paper, a continuum shell based finite element (FE) model is introduced to predict the impact and compressive strength after impact (CSAI) response of fiber reinforced polymer matrix composite (FRPC) laminates of various traditional and non-traditional layup orientations. The FE model predicts the impact damage in the laminate. The impact results are then directly used to predict the CSAI of the structure. The model uses in-plane progressive damage and failure modeling coupled with discrete cohesive elements to capture the necessary failure mechanisms. Enhanced Schapery Theory captures the non-linearity due to matrix micro cracking as well as macro intra-lamina matrix cracking and fiber failure. Discrete cohesive elements are implemented to capture the inter-lamina failure initiation and propagation (delaminations). The numerical predictions are compared against impact and CSAI experimental data for composite laminates of various layups. A high quality post-impact inspection using ultrasound and micro-computed tomography (microCT) scanning was utilized for detailed comparison between model results and experiments. The modeling technique was seen to be highly capable of predicting the impact response and CSAI of multiple different stacking sequences using a general mesh.