Evolution of penetration mechanism induced by strain rate effect

¹ Nanjing University of Science and Technology, School of Mechanical Engineering, Nanjing, China ;
² Army Engineering University of PLA, State Key Lab. of Disaster Prevention & Mitigation of Explosion & Impact, Nanjing, China

^* Corresponding author: ligan1205@163.com

Published online: 7 September 2018

Abstract

According to the dynamic mechanical properties, in the striking velocity range, the strain rate of the projectile and target caused by penetration can reach 10⁴~10⁶ /s. The strain rate effect increases sharply and then tends to saturation. During the penetration process, the mechanical properties of the target and the projectile change violently and present serious spatial inhomogeneity, which has a great influence on the penetration effect. In this paper, penetration experiments of granite targets by steel projectiles are carried out in the range of 1200m/s~2400m/s, the crater parameters are measured and the projectiles are recovered to obtain the macroscopic failure pattern of the projectiles and the targets. Based on the dynamic mechanical properties, an interaction model of the projectiles and the target is established, which considers the spatial and temporal distributions of the strain rates during penetration. With this model, the influences of material mechanical behaviour on penetration effect at different velocities are analysed, the formation cause and internal mechanism of penetration effect are discussed, and the influence mechanism of the strain rate effect on the penetration mechanism evolution is also revealed.