The objective of this research work was to perform a flow simulation around a running bullet and then compare and analyze three types of widely used bullet models. These are 7.62mm × 39mm, 7.62mm × 51mm, and 5.56mm × 45mm caliber popular NATO rounds respectively. Due to limited processing and computational resources, these bullet are modeled as cylindrical projectiles of similar length and diameter. Finite element analysis (FEA) are performed on these models using ANSYS explicit dynamics analysis code to investigate the effect of high velocity impact of these projectiles on a concrete plate. Three different types of meshing (coarse, fine, and fine with curvature) for each of these three cases have been used. Each projectile was fired at a different velocity. These velocities are selected in consultation with Hornady Manufacturing, Inc which has done extensive research on these bullets. The selected firing velocities for 7.62mm × 39mm, 7.62mm × 51mm, and 5.56mm × 45mm caliber bullets are 2021ft/s, 2539.4ft/s 2706.7ft/s respectively.
Overall, the simulation result of explicit dynamics clearly demonstrated cavitation and mushrooming of projectiles when impacting a 0.25 inch concrete plate. The 5.56mm × 45mm projectile seemed to have the largest overall total deformation values of 2.0303, 1.0487, and 0.26079 feet as obtained from simulation of the three types of mashing. This can be attributed due to the higher velocity (2706.7ft/sec) as compared to the other two cases. Similarly, the 7.63mm × 39mm has the highest average change of velocity of 144.7, 92.3, and 99.6ft/sec respectively from the three types of meshing among the three bullets which can be attributed due to its lowest impact velocity (2021ft/s).
Explosion Testing of a Polycarbonate Safe Haven Wall
