Abstract Self-sharpening has been observed in experiments and simulations of long-rod penetration. Penetration performances are influenced by different nose shapes occurred in the penetration of long rods made by different materials. In this paper, to model this nose shape effect, the resistance of the target in the standard Alekseevskii-Tate model is replaced by the resistance determined by the spherical cavity expansion approximation for general nose shapes. The function of nose shape is constructed to establish a modified model of long-rod penetration, in which the nose geometry during the long rod penetration is represented by two main parameters, i.e., the diameter ratio of rod nose and shank η and the nose shape factor N * . The influences of η and N * on long-rod penetration and their mechanisms are analyzed. The penetration performance decreases with an increasing diameter ratio η , whose physical basis is the increased radial flow of rod material around the nose, which in turn, leads to the loss of kinetic energy due to larger cavity formed in the targets. The nose shape factor N * reflects the sharpness of nose shapes, and a smaller value of N * corresponds to a sharper nose. N * obviously affects the ballistic performance of long-rod penetration, however, depending on the initial impact velocity. In general, the influence of N * is relatively smaller than that of η .

中文翻译：

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伞形弹头几何形状对长杆穿透的影响

摘要 在长杆穿透的实验和模拟中已经观察到自锐化。穿透性能受不同材料制成的长杆穿透时出现的不同鼻尖形状的影响。在本文中，为了模拟这种鼻子形状效应，将标准 Alekseevskii-Tate 模型中目标的阻力替换为由一般鼻子形状的球腔扩展近似确定的阻力。构建机鼻形状函数建立长杆穿透修正模型，其中长杆穿透时机头几何形状由两个主要参数表示，即杆鼻与杆身直径比η和机头形状因子 N * 。分析了η和N*对长杆贯入的影响及其机理。穿透性能随着直径比 η 的增加而降低，其物理基础是杆材料在鼻子周围的径向流动增加，这反过来又由于在目标中形成更大的空腔而导致动能损失。鼻子形状因子N * 反映鼻子形状的锐度，N * 值越小，对应的鼻子越锐利。N * 显然会影响长杆穿透的弹道性能，但是，取决于初始冲击速度。一般来说，N * 的影响比 η 的影响要小。N * 值越小，鼻子越尖。N * 显然会影响长杆穿透的弹道性能，但是，取决于初始冲击速度。一般来说，N * 的影响比 η 的影响要小。N * 值越小，鼻子越尖。N * 显然会影响长杆穿透的弹道性能，但是，取决于初始冲击速度。一般来说，N * 的影响比 η 的影响要小。