High-Velocity Impact of Steel Spheres of Metallic Targets
NAVAL WEAPONS CENTER CHINA LAKE CA
Pagination or Media Count:
A study was made of the penetration, perforation, and fragmentation of 0.05 to 0.25-inch-thick 2024 aluminum, SAE 1020, and 4130 steel alloy plates impacted normally by 0.125-, 0.25-, and 0.375-inch-diameter AISI 52-100 hard steel spheres at velocities from 2,800 to 8,800 fps. The drop in projectile velocity was found to decrease just above the ballistic limit, then steadily rise with increasing initial bullet speed in all target-projectile configurations. The first trend was predicted by a relation based on a simple momentum balance, whereas a more precise analysis provided reasonable correspondence with the data over the entire velocity range. Strain gage results showed a decrease of dishing relative to radial target motion with increasing impact velocity. Displacement-time curves were constructed using measured initial and terminal projectile velocities, fragment dimensions, and Kerr cell records. Force histories of the projectiles were then computed from these data using an empirical relation developed previously. Peak forces obtained were in reasonable agreement with calculations from a triangular impulse of the proper duration and of magnitude equal to the measured change in momentum.
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