Oblique penetration of ogive-nosed projectile into aluminum alloy targets

To better understand the oblique penetration behavior of ogive-nosed projectile into aluminum alloy targets, penetration experiments with impact velocities ranging from 700m/s to 1100m/s and oblique angles of 0, 10 degrees, 20 degrees and 40 degrees were conducted. The Length to Diameter (L/D) of the projectiles were 3 and 4, respectively. Failure modes of target and penetration trajectory were obtained from penetration experiments. Based on the local interaction theory (LIT) and resistance to penetration in dynamic expansion theory (DET), a model to depict penetration trajectory was developed by taking the effects of free surface and wake separation/reattachment into account. The effects of free surface and wake separation/reattachment on penetration trajectory were analyzed by combining the experimental data and calculated results. The results showed that the calculation results were in good agreement with the corresponding experimental data. Besides, influences of oblique angle, impact ve locity, and L/D of projectile on the penetration trajectory were discussed based on the calculation and experimental result. Ranges of increments of attitude angle of projectiles and oblique angle at the impact velocity of 900m/s were 98% to 274% and 10 degrees to 30 degrees, respectively. Similarly, the increments of attitude angle of projectile varied from 205% to 128% as the impact velocity increased from 800m/s to 1000m/s when the oblique angle was 20 degrees. When it come to the influence of L/D of projectile on the penetration trajectory, the increments of attitude angle of projectiles were 178% and 79.5% for the L/D were 3 and 4, respectively. In summary, the penetration trajectory became more stable with the increase of L/D of projectile and decrease of impact velocity and oblique angle.