Exploring the high-velocity impact dynamics of polyurea-coated aluminum alloy plates: Numerical insights into flat and curved surfaces

This research investigates the ballistic impact performance and energy absorption capabilities of polyurea-coated aluminum alloy plates (250 mm × 250 mm, 6 mm thickness) under high-velocity oblique impacts. Spherical aluminum alloy projectiles with a diameter of 40 mm were used for the impacts. A nonlinear finite-element analysis was conducted using LS-DYNA, replicating the experimental impact test setup from the literature. The numerical findings were validated by comparing them to experimental data available in the literature for flat plates under normal impact at varying velocities, demonstrating a strong correlation with a deviation of only 1.3%. The study explores the effects of various oblique impact angles (0°, 15°, 30°, 45°, and 60°) and panel curvature on the ballistic limit and energy absorption behavior. Results show that the ballistic limit velocity for both flat and curved panels increases significantly with higher impact angles. For flat plates, the ballistic limit increases by 1.6%, 3.3%, 12.2%, and 41.6% at 15°, 30°, 45°, and 60°, respectively, while the curved panels show ballistic limits approximately 11% higher than flat plates. The energy absorption capacity peaks at a 60° angle of incidence, with curved plates absorbing around 20% more energy than flat plates. Damage behavior analysis revealed that delamination, petalling, and spalling were the predominant failure modes, with the extent of delamination increasing with the angle of incidence, particularly at 60°. The study highlights the significant role of impact angle and curvature in improving ballistic performance and energy dissipation, with curved panels exhibiting superior energy absorption and higher ballistic limits compared to flat plates.