Energy absorption mechanisms of modified double-aluminum layers under low-velocity impact

Laminated multiple metal or alloy sheets have been widely used in protective structures. However, energy absorption mechanism remains unclear for those laminates with different interface and surface conditions under low-velocity impact. This study investigates the effect of interface and surface modified double aluminum sheets under drop-weight loading. The experimental results showed that epoxy-bonded double sheets did not dissipate more energy than free-contact sample. The simulation results agree well with the experimental data at low cohesive stress of the epoxy adhesive, and friction plays an important role in absorbing impact energy for free-contact sample. However, at high interface cohesive stress as simulated, epoxy-bonded samples absorb more energy than free-contact ones. Further experiments indicated that sample with grease spread front surface is more sensitive in improving energy absorption than sample with grease applied in between two layers. These results are important reference for designing laminated composites to improve impact resistance.