活性Whipple结构超高速撞击防护性能实验研究

以二级轻气炮作为加载手段，针对以PTFE/Al活性材料为防护屏的Whipple防护结构，开展不同弹丸尺寸、不同碰撞速度的超高速撞击实验。利用激光阴影照相设备，获得并分析了碎片云特性；通过回收的防护结构靶板，研究了活性材料防护结构超高速撞击条件下的后板损伤特性；通过与经典Christiansen撞击极限方程对比，获得活性材料Whipple结构防护性能，并拟合得到新型防护结构的撞击极限曲线。结果表明，相较于同面密度铝合金材料，活性材料超高速撞击条件下的冲击起爆反应使得碎片云中具有侵彻能力的碎片大幅减少，从而显著提升航天器的防护能力，撞击速度为2.31 km/s时最大可提升45%。

Experimental investigation into performances of an active Whipple shield against hypervelocity impact

With the continuous increase of centimeter-scale space debris, the exploration and design of new high-performance shields has become an urgent need. Based on the shield of active materials, the hypervelocity impact experiments with different projectile sizes and impact velocities were carried out by using a two-stage light gas gun. The image characteristics of debris clouds under different impact conditions were obtained and analyzed by laser shadowgraph photography. The damage characteristics of the rear wall of the active Whipple shield were studied. Through the statistical analysis of the number of craters, the influences of active materials on the fragmentation of projectiles under different impact velocities were obtained. Compared with the classical Christiansen ballistic limit equation, the protective performance of energetic active material shield was obtained, and the ballistic limit curve of the new shield was fitted. Analysis suggests that shock initiation characteristics of active materials under impact enhanced the shield performance. When impacted by the space debris, active material shield firstly uses its mechanical strength for primary crushing. During this process, the energetic material shield has an explosive reaction with an instantaneous temperature being as high as 3 800 K, which can promote fragmentation, melting and reduce the size of the space debris. At the same time, the explosion products with high temperature, pressure and high speed motion produce a negative acceleration to the projectile fragments, reducing the axial kinetic energy. The explosion products of the active materials are mostly gaseous, which greatly reduce the number of the fragments with penetration ability in the debris cloud. The penetration failure of the rear plate only comes from the fragments generated by the fragmentation of the projectile. Under the combined action of impact and explosion, the active materials shield can not only fully break and decelerate space debris, but also greatly reduce the number of solid debris in debris cloud, thereby produce a sharp rise in the spacecraft protection ability, and the maximum protection ability can be increased by 45% when the velocity is 2.31 km/s.