Experiment and numerical modeling of high-velocity impact behavior of Z-pinned composite laminates

In this work, the high-velocity impact behavior of Z-pinned composite laminates is investigated by experiment and numerical modeling. High-velocity impact tests for Z-pinned composite laminates with different Z-pin spacing are carried out. The damage states in Z-pinned composite laminates are experimentally characterized to investigate the mechanisms underlying high-velocity impact damage. Delamination results are obtained using ultrasonic C-scan and scanning electron microscope techniques. It is found that the fiber breakage area decreased with the presence of the Z-pins, whereas matrix cracking increased. An appropriate numerical model incorporating a zero-thickness cohesive zone formulation is developed to predict the impact response of Z-pinned composite laminates. In this model, the specific cohesive elements are inserted in each layer, which reflects reinforcement effect of Z-pin. This approach can effectively capture both the spontaneous initiation and subsequent growth of delamination cracks. Consequently, the numerical model is validated through comparison of simulated and experimental high-velocity impact responses of Z-pinned laminates, demonstrating both accuracy and effectiveness. The characteristic values of impact mechanical responses and damages are investigated by the numerical model. In addition, the approach can be adapted to systemically study Z-pinned composites with different designed parameters under high-velocity impact.