椭圆变截面弹体斜贯穿薄靶姿态偏转机理

随着新型武器平台的发展，具有良好平台适应性、高升阻比及隐身性能等特点的异形截面（椭圆形及变截面椭圆形）战斗部开始受到广泛关注。为探究椭圆变截面弹体斜贯穿薄靶机理与姿态偏转规律，对3种不同截面（圆形、椭圆形、变截面椭圆形）弹体斜贯穿双层945舰船薄钢板实验过程及结果进行整理与分析，根据椭圆变截面弹体贯穿过程、靶板破坏失效模式与弹体受力特征，将贯穿过程分为弹体头部压入阶段、弹体头部贯穿阶段、过渡阶段与弹身贯穿阶段。基于能量守恒、虚功原理分阶段分析弹体受力特征，建立弹体姿态偏转理论模型。通过对已有实验和数值模拟结果与理论模型所得结果进行对比，验证理论模型的可靠性。采用该理论模型着重讨论弹体撞击速度、初始倾角、质心位置、弹体翻滚角及椭圆截面长短轴之比等参数对椭圆变截面弹体姿态偏转的影响。结果表明：随着椭圆变截面弹体初始撞击速度的增加，弹体姿态偏转角度呈现指数型减小趋势；随着椭圆变截面弹体初始倾角的增大，弹体姿态偏转量增大；随着椭圆变截面弹体质心位置的后置，弹体姿态偏转角度增大；椭圆变截面弹体以不同的翻滚角撞击靶板时，弹体姿态偏转角度不同，γ_pt=0°较γ_pt=90°时弹体姿态偏转角度更大；当γ_pt=0°时，椭圆变截面弹体椭圆截面长短轴之比增大，弹体姿态偏转角度随之增大；当γ_pt=90°时，规律则相反。

Attitude Deflection Mechanism of Projectiles with Variable Elliptical Cross-sections Obliquely Perforating Thin Targets

With the development of new weapon platforms, warheads with novel cross-sections (elliptical and variable elliptical cross-sections) have drawn wide attention due to high platform adaptability, lift-drag ratio, and stealth performance. This study investigates the oblique penetration mechanism and the attitude deflection of projectiles with variable elliptical cross-sections by examining projectiles with three types of cross-sections (circle，elliptic，and tapered elliptic) obliquely penetrating a double-layer thin steel plate through experiments. Based on the failure mode of the target plate and the mechanic characteristics of the projectile body, the penetration process is divided into four stages, namely press-in of the projectile nose, penetration of the nose, transition, and penetration of the projectile body. The mechanic characteristics of each projectile at each stage are also analyzed based on the law of energy conservation and virtual work principle. A theoretical model is constructed for the projectile's attitude deflection. The theoretical model is validated through comparing the experimental and simulation results. The model is used to study how the attitude deflection of projectiles with variable elliptical cross-sections is affected by different parameters, including impact velocity, initial oblique angle, centroid position, roll angle, and the long to short axis ratio of the elliptical cross-sections. The results show that as the impact velocity of the projectile increases, the attitude deflection angle decreases exponentially; the deflection increases as the initial oblique angle increases; the deflection increases as the centroid moves away from the projectile nose; the deflection angles vary when the projectile hits the target from different rolling angles; the deflection at γ_pt=0° is greater than that when γ_pt=90°; as the long to short axis ratio increases, the deflection increases when γ_pt=0°, yet it decreases when γ_pt=90°.