Ballistic Impact
At low impact velocities (say a few hundred meters per second), the penetration resistance of a material is governed by the dynamic deformation mechanisms within the projectile and target. However, as the impact velocity increases into the hypervelocity regime (several thousand meters per second), hydrodynamic effects dominate and the penetration response becomes controlled by only the density of the impacted material and projectile. Since the resistance of a material to penetration by low velocity projectiles is controlled by dynamic deformation and fracture mechanisms, the materials science community has been greatly interested in their optimization. In general the mechanisms that are activated depend upon the thickness, strength, ductility, toughness, acoustic impedance and density of both the target material and projectile and the velocity of the projectile.