基于缩放实验的Whipple结构撞击特性

针对航天器空间碎片防护问题,基于缩放实验方法,开展了7 km/s以上超高速碰撞仿真研究.建立了单板和Whipple防护结构的仿真模型,并对铝-铝撞击问题和镉-镉撞击问题进行了多工况仿真.通过实验结果与数值仿真的对比,表明了数值仿真技术的正确性,并从仿真角度验证了缩放实验方法的有效性.对缩放实验方法的适用性进行了仿真验证,结果表明该方法对弹丸形状适用性较好,对3～4 km/s以上撞击速度的适用性较好,但对Whipple防护结构后板存在一定误差.分析了Whipple结构后板的失效模式,提出了失效模式的不连续性导致了缩放实验方法的误差.最后通过数值仿真计算了Whipple结构7 km/s以上弹道极限特性,提出了失效模式的不连续性造成了在该速度段弹道极限曲线的分叉现象.

Investigation of Whipple shield hypervelocity impact based on scaled test method

Hypervelocity impact above 7 km/s was investigated based on scaled test method for spacecraft shielding issue. Simulation models of single bumper and Whipple shield were built, both Al-Al impact and Cd-Cd impact problems were simulated under multiple cases. The comparison of test and simulation showed the validity of simulation technique and scaled test method was also verified from the view of simulation. Adaptedness analysis was applied on scaled test method. The result shows that the method is well adapted for the impactor shape and impact velocity, but has larger error for the rear wall of Whipple shield. Failure mode analysis of Whipple shield rear wall indicated that the error was caused by the discontinuity of failure mode. Ballistic limit was investigated finally for Whipple shield above 7 km/s. The result shows that the discontinuity of failure mode in the rear wall cause the bifurcation of ballistic limit curve within this velocity range.