High-speed penetration of ogive-nose projectiles into thick concrete targets: Tests and a projectile nose evolution model

The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 mm. This study aims to fill the gap in the experimental and analytical study of the evolution of the nose shape of larger hollow projectiles under hypersonic penetration. In the hypersonic penetration test, eight ogive-nose AerMet100 steel projectiles with a diameter of 40 mm were launched to hit concrete targets with impact velocities that ranged from 1351 to 1877 m/s. Severe erosion of the projectiles was observed during high-speed penetration of heterogeneous targets, and apparent localized mushrooming occurred in the front nose of recovered projectiles. By examining the damage to projectiles, a linear relationship was found between the relative length reduction rate and the initial kinetic energy of projectiles in different penetration tests. Furthermore, microscopic analysis revealed the forming mechanism of the localized mushrooming phenomenon for eroding penetration, i.e., material spall erosion abrasion mechanism, material flow and redistribution abrasion mechanism and localized radial upsetting deformation mechanism. Finally, a model of high-speed penetration that included erosion was established on the basis of a model of the evolution of the projectile nose that considers radial upsetting; the model was validated by test data from the literature and the present study. Depending upon the impact velocity, v₀, the projectile nose may behave as undistorted, radially distorted or hemispherical. Due to the effects of abrasion of the projectile and enhancement of radial upsetting on the duration and amplitude of the secondary rising segment in the pulse shape of projectile deceleration, the predicted DOP had an upper limit.