Abstract

An understanding of the response and perforation of thin plates to high speed rod impact is very important for design and assessment of protective structures such as whipple shields for spacecrafts and spaced armors in tanks/armoured vehicles. To this end, a theoretical and numerical study is presented herein on the perforation of thin metallic plates struck normally by long rods at velocities greater than 1.5 km/s approximately. Firstly, a theoretical model for erosion length of a long rod perforating a thin metallic plate is developed on the basis of the laws of conservation of mass, momentum and energy, which can be viewed as an extension of the previous work. In particular, an empirical equation for α (angle of relaxation) is first derived on the basis of the analysis of numerical results obtained in the present study and then verified against available test data. Secondly, an overview is presented of the existing equations for hole diameter. Finally, an empirical equation for hole diameter in thin metal plates is developed by means of dimensional analysis. It transpires that the theoretically predicted erosion lengths are in good correlation with the numerical (SPH) results for long rods perforating thin metallic plates both of which are made of different materials at impact velocities greater than 1.5 km/s approximately. It also transpires that the newly developed dimensionless formula for hole diameter produces better and more consistent results than those from the existing equations in a wider range of impact conditions.

摘要

了解薄板对高速杆冲击的响应和穿孔对于保护结构的设计和评估非常重要，例如航天器的鞭状防护罩和坦克/装甲车辆中的间隔装甲。为此，本文对薄金属板的穿孔进行了理论和数值研究，该穿孔通常由长杆以大约大于 1.5 公里/秒的速度撞击。首先，根据质量、动量和能量守恒定律，建立了长杆穿孔金属薄板的侵蚀长度理论模型，可以看作是前人工作的延伸。尤其，α（松弛角）的经验方程首先基于对本研究中获得的数值结果的分析得出，然后根据可用的测试数据进行验证。其次，概述了现有的孔径方程。最后，通过量纲分析建立了薄金属板孔径的经验方程。结果表明，理论预测的侵蚀长度与长杆穿孔薄金属板的数值（SPH）结果具有良好的相关性，这两种金属板均由不同材料制成，冲击速度大约大于 1.5 公里/秒。