Abstract:
Interlaminar delamination is a crucial failure mode in CFRP/Al hybrid laminates under low‑velocity impact. Through drop‑weight impact tests and progressive damage analysis, this study systematically investigated the effects of surface treatment methods as well as the interleaving position and number of nanofiber membranes. The results indicated that nanofiber membrane interleaving improved the impact resistance of mechanically ground specimens more significantly than that of plasma‑treated laminates, with the optimal performance achieved when the membrane was positioned at the aluminum/adhesive interface. Furthermore, by selectively reinforcing local interfaces to construct strong-weak gradient distribution, the laminate maintained load-bearing capacity in critical regions while enabling un-reinforced interfaces to absorb energy through delamination propagation, thereby promoting ductile failure. Placing nanofiber membranes at the three middle and upper interfaces was identified as the optimal local toughening strategy. This approach increased the total energy absorption by up to 52.9% compared to the fully reinforced specimens, while maintaining a high peak impact force and effectively suppressing delamination damage, demonstrating favorable overall performance and cost-effectiveness under various impact energies.