Study of destruction of thin film structure by hyper-velocity impact

未来的大型空间结构，例如太阳能卫星，将采用薄膜结构。对于在轨大型结构而言，空间碎片和流星体以每秒数公里以上的超高速撞击是不可避免的。本研究旨在研究超高速对薄膜结构的影响。空间与宇航科学研究所的轨道炮系统已用于撞击实验。轨道炮可以将聚碳酸酯制成的1克弹丸加速至4〜5公里/秒。实验中研究了薄膜的冲击破坏、弹射器以及弹丸的破坏。结果发现，弹射器向前扩展了70度，对第二片目标造成了严重破坏。破坏第二层薄膜的喷射器的总能量与喷射薄膜的质量和弹丸速度的平方成正比。撞击处产生的等离子体向前以与弹丸相同的速度传播，但向后以较低的速度（即双极扩散速度）传播。弹丸的破坏程度取决于薄膜靶的表面密度。对于速度为4〜5 km/s的聚碳酸酯弹丸，面密度的阈值约为0.1g/cm^2。如果假设在声波在射弹中传播的时间内将冲击力施加到射弹上，则该阈值对应于射弹的压缩强度。还研究了最小化冲击破坏的薄膜结构。事实证明，格子状划痕结构对于抑制冲击破坏的传播非常有效。对于格子状的加强结构，破坏更为严重，但仅限于加强结构包围的部分。这些成果为在太空构建大型薄膜结构提供了重要的工程基础。较少的

A large space structure in the future, such as the solar power satellite, will use a thin-film structure. For the large structure in orbit, hyper-velocity impact of the space debris and meteoroid at a velocity more than several km/sec cannot be avoided. This research is aimed to study the hyper-velocity impact on a thin film structure. A rail gun system at the Institute of Space and Astronautical Science has been used for the impact experiment. The rail gun can accelerate a projectile of 1gram made of polycarbonate up to 4〜5 km/sec. In the experiment, the impact destruction and ejectors of the thin film have been studied as well as the destruction of the projectile. It is found that the ejectors expanded in 70 degrees in the forward and lead a serious destruction in the second film, target. The total energy of the ejectors that destroy the second film is in proportion to the mass of ejected thin film and square of the projectile velocity. The plasma which is generated at the impact pro … More pagates at the same velocity of the projectile in the forward, but at a lower velocity, the bipolar diffusion velocity, in the backward. The destroy of the projectile depends on the surface density of the thin film target. For the polycarbonate projectile at 4〜5 km/s, the threshold of the surface density is around 0.1g/cm^2. This threshold corresponds to the compression strength of the projectile if the impact force is assumed to be applied to the projectile during the time for the acoustic wave to propagate in the projectile. The thin film structure to minimize the impact destruction is also studied. It is proved that the scratched structure in the lattice-shape is quite effective to suppress the propagation of the impact destruction. For the reinforced structure in the lattice-shape, the destruction is more serious but is localized in the segment surrounded by the reinforced structure. These results give an important engineering basis for the construction of a large thin film structure in space. Less