Experimental and Theoretical Study of high-velocity penetration of long rod projectiles into sand

Results of computations with the use of improved modified Alekseevskii–Tate theory (IMATT) are compared to experimental data on high-velocity penetration of long rod projectiles into sand in the impact velocity range of $V_0$ = 0.5–3.5 km/s. Projectiles were made of three different metals: M1 copper, WNZh tungsten heavy alloy and 30KhGSA steel. The value of hardening coefficient $k$ in the linear dependence of the projectile material yield on pressure could be determined using IMATT and experimental data on dependence of differential penetration coefficient K on the penetration velocity. At penetration in regime of the hydrodynamic erosion of projectile, differential penetration coefficient $K$ could be approximated just by dependence on the ratio of the impact velocity of penetration to the value of the critical velocity, above which the projectile deforms plastically during penetration. The values of the critical velocity may differ for specific projectile material properties as well as the density and the humidity of sand.