This study numerically investigates the high-velocity impact response of aluminum plates under varying thicknesses and inclination angles, with comparative analyses against steel targets to identify material-dependent penetration behavior. Penetration analyses were performed to examine energy partition, failure mode, and ballistic resistance as functions of target thickness, impact obliquity, and material properties. Aluminum plates exhibited larger dynamic deformation and a greater transient kinetic energy component than steel, particularly in thinner plates, where frictional dissipation associated with relative sliding was more pronounced. Within the investigated thickness range, steel showed petaling, whereas aluminum failed by plugging, highlighting clear differences in penetration characteristics according to material type. A critical inclination angle was identified for each thickness, significantly influencing energy dissipation and penetration resistance. Ballistic limit velocities extracted using the energy-based Recht–Ipson relation showed consistent thickness-dependent trends and physically reasonable transition behavior. These findings provide insight into impact energy transfer mechanisms and offer a foundational basis for energy-equivalent plate modeling in highvelocity structural response assessment.
Kim et al. (Thu,) studied this question.