在椭圆横截面弹体正侵彻下有限厚铝靶的破坏模式及响应特性

基于30 mm口径弹道炮平台，开展了3种不同椭圆横截面弹体在200~600 m/s撞击速度范围内正侵彻2A12铝靶的实验，获得了2A12铝靶的破坏形貌及弹体的剩余速度。在此基础上，建立了相应的数值模型，结合实验结果验证了所建模型的有效性，并系统分析了弹体横截面长短轴长度比对靶体的破坏情况及响应特性的影响。研究结果表明:弹体最大横截面面积是影响弹体剩余速度的主要因素，而弹体横截面长短轴长度比对弹体剩余速度的影响较弱；在圆形横截面弹体侵彻下靶体背部形成的花瓣大小和形状一致，空间分布均匀，而在椭圆横截面弹体侵彻下，随着弹体横截面长短轴长度比的增大，靶体背部形成的花瓣数量增加、尺寸变小，且在短轴方向的花瓣数量和靶体表面隆起高度均大于长轴方向的；靶体在圆形横截面弹体侵彻下的径向位移、径向应力和切向应力与其在椭圆横截面弹体侵彻下的显著不同，前者沿周向方向各点的变化规律基本一致，靶体处于简单的压缩状态，切向应力为零，而后者各点的应力状态与弹体横截面长短轴长度比和周向角密切相关，靶体受到压缩和剪切应力的耦合作用。

Failure modes and response characteristics of finite-thickness aluminum targets under normal penetration of elliptical cross-section projectiles

By means of a 30-mm-caliber ballistic gun platform, a series of experiments were carried out on 2A12 aluminum targets subjected to normal penetration by three kinds of 30CrMnSi2A steel projectiles with different elliptical cross-section shapes in the striking velocity range from 200 m/s to 600 m/s. The residual velocities of the projectiles and the failure modes of the targets were experimentally obtained. Based on the experimental results, the corresponding numerical models were established and verified. And the influences of the major-to-minor axis length ratios of the projectile cross-sections on the failure modes and response characteristics of the targets were systematically analyzed. The results show as follows. The maximum cross-sectional areas of the projectiles are the main factor affecting the residual velocities of the projectiles, while the major-to-minor axis length ratios of the projectile cross-sections have little effect on the residual velocities. Therefore, in engineering applications, the engineering model for the circular cross-section projectile penetrating a target can be directly used to calculate the residual velocity of the elliptical cross-section projectile with the same maximum cross-sectional area. In addition, under normal penetration of the circular cross-section projectiles, the sizes, shapes and distribution of the petals induced at the back faces of the targets are uniform. However, under normal penetration of the elliptical cross-section projectiles, as the major-to-minor axis length ratios of the projectile cross-sections increase, the numbers of the petals induced at the back faces of the targets increase and the petal sizes decrease, and the petal numbers and the uplifted height in the minor axis direction are greater than those in the major axis direction. The radial displacement, radial stress and tangential stress of the targets under the normal penetration of the elliptical cross-section projectiles are obviously different from those of the targets under the normal penetration of the circular cross-section projectiles. Under normal penetrations of the circular cross-section projectiles, the above response characteristics of the targets change basically the same along the circumferential directions and the targets are under simple compression states with the tangential stress of zero. But, under normal penetrations of the elliptical cross-section projectiles, the stress states of different points of the targets are closely related to the major-to-minor axis length ratios and the circumferential angles of the projectiles, and the targets are subjected to the coupling effects of the compression and shear stresses.