Effect of adhesive interface on the ballistic performance for double-layered aluminum plates impacted by blunt projectile

The double-layered metallic structures are widely used in various engineering designs due to their excellent impact resistance and lightweight. In this paper, the effects of thickness configuration and interface adhesive on the impact resistances for double-layered aluminum plates against blunt projectiles were experimental and numerical investigated. Above all, ballistic experiments were conducted using a gas gun to investigate the impact resistance of monolithic plates, non-bonded and adhesively bonded double-layered plates with identical total thickness. Based on experimental results, the effects of thickness configurations and adhesive interfaces on impact resistances were obtained. Subsequently, numerical simulations were performed, and their results were validated against experimental data, confirming the reliability of our numerical methodology. Leveraging this validated approach, the out-of-plane deformation features, failure modes, energy dissipation modes, and adhesive debonding modes were analyzed in detail. Moreover, the influences of adhesive layer thickness, plate thickness, and super-velocity impact on the impact resistances of plates against blunt projectiles were studied. The results indicated that an adhesive layer significantly suppressed deformation disparity between front and rear plates. Moreover, the adhesive application completely altered the evolution trends of both ballistic limit velocities and energy dissipation mode along the thickness configurations. Crucially, due to stress concentration at the interface, both bonded and non-bonded double-layered plates exhibited inferior impact resistances against blunt projectiles compared to monolithic plates with the same total thickness.