Trajectory and loads for oblique penetration into concrete targets by rigid projectile

This paper studies the trajectories and loads of rigid projectiles penetrating into concrete targets with oblique and attack angles, based on differential area force law with an empirical model of free surface effect. Investigations are conducted using 450kg, 300-mm-diameter ogive-nose projectiles, with striking velocities from 600 to 1000m/s, oblique angles from 5° to 25° and attack angles from 1° to 5°. The characteristics of trajectories and loads are summarized. An important characteristic is that the turning of trajectory direction only happens at the earlier stage of penetration, and then the trajectory converge to straight line and keep linear motion until the end. Consistent with the trajectory, the attack angle, lateral acceleration and moment all occur at this stage. The axial acceleration is mainly determined by the initial velocity, but the lateral acceleration and moment are determined not only by initial velocity but also by the initial oblique and/or attack angles. In terms of maximum loads of lateral acceleration and moment, the combined influence of initial oblique and attack angles is larger than a single factor. There exist a proper negative attack angle which can minimize the trajectory turning in oblique penetration cases.