【摘要】 低地球轨道的各类航天器易受到微流星体及空间碎片的超高速撞击。这些撞击损伤航天器飞行的关键系统,进而导致航天器发生灾难性失效。为了保证航天员的安全及航天器的正常运行,微流星体及空间碎片防护结构设计是航天器设计的一个重要问题。采用AUTODYN软件进行了弹丸超高速正撞击及斜撞击防护屏所产生碎片云的SPH法数值模拟,给出了二维及三维模拟结果;研究了防护屏厚度、弹丸形状、撞击速度以及材料模型等对碎片云的影响。模拟结果同高质量实验研究的结果进行了比较,模拟的碎片云形状和碎片云特征点的速度同实验相吻合。验证了数值模拟方法的有效性。更多还原

【Abstract】 Tin and lead beads are chosen to conduct the high velocity impact experiments with an explosive plane wave generator.The impact velocity is about 2 km/s.A metallurgic picture of the recovered specimen shows that there are four bands along the interfaces between tin and lead.The width across the bands is about 60～80 μm.The SEM examination discloses that these bands are the mass mixing regions of tin and lead.The dynamic diffusion coefficient of the experiments is 0.9 cm~2/s,which is much higher than that at quasi-static case. A discrete element simulation (DEM) demonstrates the process and mechanisms of the observed mass mixing for Pb-Sn beads under shock loading at meso-scale qualitatively.更多还原