2002 Fiscal Year Final Research Report Summary
Study of destruction of thin film structure by hyper-velocity impact
| Project/Area Number |
12450397
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Aerospace engineering
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| Research Institution | The Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency |
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Principal Investigator |
SASAKI Susumu The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Department of Space Information and Energy, Professor, 宇宙科学研究本部・宇宙情報・エネルギー工学研究系, 教授 (00092221)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Koji The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Department of Space Information and Energy, Associate professor, 宇宙科学研究本部・宇宙情報・エネルギー工学研究系, 助教授 (90321570)
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| Project Period (FY) |
2000 – 2003
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| Keywords | Large space Structure / Solar power Satellite / Thin film Structure / Hyper-velocity impact / Rail gun / ejector / Impact destruction |
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| Research Abstract |
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
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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
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