密度梯度薄板超高速撞击特性的实验研究

以二级轻气炮作为加载手段,在撞击速度范围为4.0—7.0 km/s内获得了Ti6Al4V/Ly12 Al/聚酰胺纤维密度梯度薄板的穿孔特性、验证板损伤特性和弹道极限特性.与Ly12 Al薄板的相应实验结果的对比显示,在相同撞击速度下,该密度梯度薄板的穿孔直径更大,且随撞击速度的增大而增加;其验证板上的撞击坑尺寸小,且随撞击速度的增大而减小;其弹道极限比Ly12 Al薄板的弹道极限高50%以上.分析认为,超高速撞击下Ti6Al4V/Ly12 Al/聚酰胺纤维密度梯度薄板中高阻抗的Ti6Al4V产生的峰值冲击压力比Ly12 Al薄板的峰值冲击压力高,这增强了对弹丸的破碎能力;而其中的聚酰胺纤维层延长了冲击波在薄板中的传播时间,增大了冲击波的耗散,使撞击过程中转化的不可逆功增多,从而消耗了弹丸更多的动能.使用这种密度梯度材料作为防护屏具有很好的抗撞击能力,在航天器空间碎片防护工程应用中具有很大的潜力.

Experimental study on hypervelocity impact characteristics of density-grade thin-plate

Hypervelocity impact (HVI) characteristics of Ti6Al4V/Ly12 Al/polyamide fibre density-grade thin-plate are investigated experimentally in a velocity range of 4.0–6.5 km/s by using two-stage light gas gun. The perforation in target, damage to witness wall, and ballistic limit curve are obtained and compared with those in the case of aluminum thin-plate. The results show that the diameter of the perforation hole is larger than that of aluminum thin-plate, the crater size in witness plate is smaller, and the ballistic limit curve is 50% larger than the latter. The analysis of shock wave propagation and the calculation of energy dissipation property in the density-grade thin-plate show that higher peak shock pressure is produced in it, and it has longer pressure duration time. Thus, more dissipation energy is consumed than in the case of aluminum thin-plate. So the density-grade thin-plate has a very good performance in withstanding HVI, and is promising in engineering application, e.g. protecting spacecraft from HVI of micro-meteoroid and orbital debris.