Projectile impact performance of steel-lightweight aggregate concrete-steel panels

Steel-lightweight aggregate concrete-steel (SLCS) panels have potential applications in protecting critical infrastructure against impacts from unmanned aerial vehicles, aircraft engines, and other large-mass debris. Therefore, in the present study, gas gun tests and numerical analyses were conducted to investigate their projectile impact resistance. The deformation development, damage characteristics, and energy dissipation of the panel during and after the impact were examined. Furthermore, the influence of important factors such as impact velocity, stud spacing, concrete core thickness, faceplate thickness, rear plate thickness, and number of impacts on the panel response was then discussed in detail. The results showed that the response of the SLCS panel was governed by the coupling of faceplate indentation or penetration, punching damage of the concrete core, and rear plate deformation. With increasing impact energy, the response mode transformed from relatively localized damage to pronounced local penetration and eventually perforation failure. An appropriate reduction in stud spacing enhanced the composite panel resistance and the overall energy dissipation capacity. However, an excessively small stud spacing intensified response localization and reduced the impact resistance. Moreover, for the same mass increment, increasing the rear plate thickness led to the greatest improvement in impact resistance. In addition, repeated impacts enlarged the response region and made the cumulative damage effect more evident, whereas a single impact was more likely to produce deeper local penetration. Comparisons under equal total kinetic energy and equal cumulative incident momentum showed that kinetic energy primarily governed damage and deformation. This study provided a reference for the impact-resistant design of the SLCS panels.