超高速撞击下PTFE/Al含能材料薄板的载荷特性分析

不同于传统惰性材料的空间碎片防护结构,含能材料防护结构在超高速撞击下的冲击起爆特性是其防护能力得以提高的根本原因。PTFE/Al含能材料防护结构的冲击起爆特性改变了弹丸强冲击载荷下的破碎机制,弹丸内部的冲击压力对于分析含能材料在超高速撞击下的防护机理具有重要意义。对超高速撞击试验中回收的PTFE/Al防护结构后板进行损伤特性分析,获得了对应速度条件下弹丸的破碎特性。基于一维冲击波理论,分析PTFE/Al靶板在超高速撞击条件下的冲击响应过程,结合考虑化学反应效率的热化学反应模型,获得了弹丸在碰撞与爆炸联合作用下的载荷特性,通过与试验结果对比验证,获得该材料完全反应的临界撞击速度约为1800 m/s,弹丸的临界破碎速度为2875 m/s,小于铝防护结构中对应的临界破碎速度。给出了弹丸在PTFE/Al、铝两种防护结构中产生相同冲击压力时对应的临界速度,分别为弹道段的800 m/s和破碎段的3580 m/s。

The loading characteristics of PTFE/Al energetic materials under hypervelocity impact

Unlike the conventional orbital debris shield with inert materials, the impact-initiation property of energetic materials under hypervelocity impact plays a fundamental role in improving the protection ability. For the fragmentation mechanisms of the projectile under hypervelocity impact are closely related with the impact-initiation property, it is very important to analyze the protection mechanism of the energetic materials and the shock pressure generated by impact and explosion. Firstly, the fracture characteristics of projectiles under the experimental conditions are determined through analyzing the damage characteristics of the rear wall. Then, based on the one-dimensional shock wave theory, the impact pressure of projectiles is obtained by combining with the thermal reaction model for the chemical reaction efficiency. From the experimental results, the critical impact velocities when the projectile produces the same impact pressure in both energetic and inert materials for the PTFE/Al energetic complete reaction and the fragmentation initiation threshold of the projectile are obtained.