Investigation on the Penetration Performance of Different Fragments against Two Typical Lattice Structures

Due to their excellent performance and high energy absorption capabilities, lattice structures are widely used in aerospace structures such as unmanned aerial vehicles (UAVs). To effectively combat UAV swarms, investigating the penetration performance of different fragments into lattice structures has become a crucial defense topic. In this study, combining finite element numerical simulations with ballistic gun experiments, we systematically investigated the penetration performance of three types of fragments with equal mass (1.1 ± 0.03 g) and distinct geometric features (square, cylindrical, and spherical projectiles) against two typical Triply Periodic Minimal Surface (TPMS) lattice structures: Gyroid and Diamond. The research focused on analyzing the variation trends of the residual velocity and residual kinetic energy of the projectiles under different initial velocities (500, 600, and 700 m/s) and various penetration angles (0° to 45°). The results indicate that under high-speed penetration conditions, the differences in fragment shape and target cell structure have a minor impact on the final residual velocity and residual kinetic energy. However, the penetration angle has a significant nonlinear effect on the damage efficiency of the target plate. As the penetration angle increases, the penetration depth of the fragments gradually increases, leading to a significantly accelerated decreasing rate in both residual velocity and residual kinetic energy. Furthermore, spherical fragments primarily cause local fragmentation and deformation during penetration, while cylindrical and square fragments tend to form truncated cone-shaped plugs. This study provides valuable insights into the selection of fragments for striking low-altitude military UAVs and offers a practical reference for the effective penetration of UAV wing structures.