Effects of structure characteristics of projectile on trajectory and loads for oblique penetration into concrete

Three groups of projectiles with different CRH values of ogive-nose, mass center locations, and cone angles of shank are designed to study trajectory and loads of oblique penetration into concrete targets. Impact conditions are taken as striking velocity 600m/s, initial oblique angle 30° and concrete target with compressive strength of 30Mpa. We employed a general differential area force law (DAFL) model of rigid projectile for oblique penetration. An empirical model of free surface effect is proposed for brittle targets. It is shown that structure characteristics have significant effects on trajectories and loads for oblique penetration, i.e. (a) The larger the CRH values, and the closer the mass center locations to the projectile end, the larger the turning angles and lateral deviations of penetration trajectories are. (b) The trajectories of projectiles with 'cone+ogive-nose' structures show more stable than those with 'cylinder+ogive-nose'. (c) All trajectories converge to straight line (linear motion) until stop in the targets, and the trajectories can be divided into turning stage and linear motion stage.