numerical investigation of double low-velocity impact and post-impact compression behavior in laminated composites

Low-velocity impact can significantly reduce the structural integrity of the laminated composites, and it can be exacerbating the damage if it occurs repeatedly. in this study, double low-velocity impacts are numerically applied on the laminates by utilizing ply-level based modeling strategy, which each ply and each interface of the laminate is explicitly modeled, with the plies represented by conventional shell elements and the interfaces are discretized using cohesive zone elements. the impact results are then directly utilized to predict the residual compressive strength of the laminates by performing compression after impact simulation. furthermore, the impact responses and the structural integrity of the laminated composites are compared for all configurations including single and double impact events for various distances. the numerical results show that in the double 0 mm case, the second impactor experiences significantly higher displacement due to reduced transverse shear stiffness from the first impact. the double 10 mm configuration exhibits the largest delamination growth, leading to the most severe compressive strength reduction from 634 mpa to 311 mpa. additionally, the results show that the distance between two impact positions provides different delamination interference mechanisms which are consistent with the previous experimental findings. overall, the results provide quantitative insights into damage mechanisms, delamination growth, and residual strength reduction, which are crucial for designing more impact-resistant composite structures. meanwhile, the implementation of a ply-level-based modeling strategy ensures high computational efficiency in predicting impact responses and compressive strength in laminated composite structures.