Effect of yaw and obliquity of cubical fragments on damage of thin targets in ballistic applications

The use of fragment-generated warheads holds paramount importance in air defense systems. A smoothbore 30-caliber powder gun was employed to launch cubical projectiles in the ballistic range of velocities from 450 to 1500 m/s. The present work is mainly focused on the effect of various impact parameters, such as yaw (0°, 23°, and 45°), obliquity (0°–75°), incident velocity (500–2000 m/s) and mass (1, 3, and 5 g) of SS304 cubical projectiles impacting thin Steel 1006 target plates. A full-scale 3D FE model considering 8-noded hexahedral elements was used to discretize the target plates/projectiles. The material behavior was characterized using J-C strength and damage models, along with Gruneisen Equation of State. An erosion algorithm was used in the explicit FE code LS-DYNA to remove undesirable elements. The target volume erosion fraction (TVEF), projectile volume erosion fraction (PVEF), residual velocities, and crater damage results obtained from series of simulations were compared with experimental findings. The study revealed that at higher obliquity angle (60°–65°) of high mass projectiles, the disintegration of the plate occurs primarily due to shock waves and energy transmitted to the target plates instead of direct contact. The findings also provide valuable insights into designing the most lethal fragments for different impact scenarios and contribute to a comprehensive understanding of impact-induced deformations and fractures under dynamic loading conditions.