Investigation on energy-absorption-based protection mechanism of polyurea-coated aluminum alloy composite (PCAA) plate under impact loading by K9 glass projectile

Abstract

To investigate the dynamic response and anti-impact characteristics of polyurea-coated aluminum alloy (PCAA) plates, impact experiments by the K9 glass projectile were first carried out with a light-gas gun. Based on the experiments, numerical simulations were conducted and validated using LS-DYNA software. After validation, the effect of polyurea coating thickness on the composite response as the impact surface under the same substrate conditions was discussed. The transverse diffusion effect and glassy transition effect were proposed in this study, and the results demonstrate better energy absorption characteristics and protective mechanisms of composite structures. The impact load is dispersed to a wider area due to the existence of polyurea coating on the impact surface characterized by the transverse diffusion effect, which will reduce the impact stress but deform a larger area plastically. In addition, our findings reveal that the glassy transition effect of polyurea determined by the average loading rate plays a significant role in improving the impact resistance characteristics of the composite structure. Finally, for the metal substrate with fixed thickness, this study demonstrates the existence of an optimal thickness of the coating as the impact surface of the PCAA plate to achieve the highest energy absorption efficiency under projectile impact conditions. The results and findings in this study provide a deep insight into the deformation and energy-absorption-based protective mechanism of PCAA targets under impact loading and may contribute to the future design of protective structures.