On the ricochet of sharp-nosed rigid projectiles from metallic plates

We present a numerical study on sharp-nosed rigid projectile obliquely impacting ductile metallic plates. We followed the trajectory changes of these projectiles including their ricochet behavior and we determined their threshold ricochet angles. These are the impact obliquities at which the projectile moves along a trajectory parallel to the plate's face. These angles were found to be related to the normalized impact velocities of the projectile/plate pair, which are defined by the ratio between the impact velocity and the ballistic limit velocity, at normal incidence, for the given pair. This numerically-derived empirical relation was shown to account for various rigid projectiles, with different nose shapes and aspect ratios, impacting aluminum and steel plates of various strengths. We also found that this relation accounts for experimental data with aluminum and steel plates obliquely impacted by 7.62 mm AP projectiles.