Trajectory prediction of the tapered projectile and grooved projectile in deep penetration

With the development of high-speed penetration mechanics, some typical special-shaped kinetic energy projectiles have been proposed, such as tapered and grooved projectiles. In the present study, we investigated the ballistic stability of those typical special-shaped projectiles under oblique penetration conditions, which, to our best knowledge, were not investigated before. Firstly, the geometrical description and surface meshing method of three typical projectiles (the cylindrical, tapered, and grooved projectiles) are given in detail. Then, a trajectory model is established based on the modified free-surface effect and the weak-separation effect, and the proposed model is verified by comparing with the existing tests data. Finally, influences of structural parameters and impacting conditions of the special-shaped projectiles on trajectory stability are discussed. It suggests that, compared with the cylindrical projectile, the tapered projectile has better trajectory stability, and a reasonable taper angle can reduce the lateral displacement on the premise of ensuring the vertical displacement of the projectile; For the grooved projectile, the grooves reduce the axis resistance from the targets, but the value of the groove radius has less influence on trajectory deflection. The results of this study provide a reference for the structural design of special-shaped projectiles to enhance trajectory stability.