Study on the trajectories’ characteristics of elliptical cross-section projectile penetration into multi-layer spaced steel targets

For studying the trajectories’ characteristics of elliptical cross-section projectiles penetrating multi-layer spaced steel targets, experimental investigation of typical projectiles penetrating multi-layer spaced Q355B steel targets has been conducted. Numerical simulations have been performed on LS-DYNA finite element software and typical results obtained have been validated by experimental results. The attitude and trajectory parameters in the penetration process and the deflection mechanism of the projectile were obtained. The influence of cross-section shape, the minor-to-major axis length ratios of the projectile cross-section, initial velocity, rotation angle and incident angle on the penetration trajectories and attitude deflection was investigated. The research results show that the penetration trajectory stability of the circular cross-section projectile is better than the elliptical and asymmetric elliptical cross-section projectile when the rotation angle is 0°. As the minor-to-major axis length ratios increase, the trajectory is more stable. The trajectory deflection reduces with higher initial velocity. When rotation angle is 90°, the penetration trajectory of both symmetric and asymmetric elliptical cross-section projectile in the incident plane is the most stable, and the trajectory deflection of the two projectiles in the horizontal plane reaches its maximum at rotation angles of 45° and 90°, respectively. The trajectory stability of asymmetric elliptical projectile when the rotation angle is obtuse is better than that at the acute angle. When the incident angle is in the range of [0°,50°], the trajectory instability and attitude deflection of projectile increase with the increase of incident angle and then decrease, and both reach the largest when incident angle is about 30°. It is also found that the projectile will separate from the target during the penetration stage of projectile nose when penetrating thin steel target in a stable attitude. When the projectile penetrates thin steel target in a large attack angle, the attachment of projectile and target mainly occurs on the upper surface of