紀要論文

スペースデブリ衝突におけるタンクの曲率と衝突損傷の関係性

RELATIONSHIP BETWEEN TANK CURVATURE AND DAMAGE IN DEBRIS IMPACTS

jpn

24368083

https://doi.org/10.15002/00030625

法政大学大学院理工学研究科

法政大学大学院紀要. 理工学研究科編

65

1

7

2024-03-24

Version of Record

Space debris in Earth orbit have been increasing year by year. This problem cannot be ignored since debris impacts cause satellites damage. One of serious scenarios is explosion of a pressure vessel due to debris impacts. To prevent further debris generation, the authors focused on catastrophic break-up of propellant tanks in satellites caused by debris impacts. There are two considerable mechanisms leading to break-up of the tank. One is caused by perforation of tank’s wall. After a perforation due to a debris impact, pressure inside the tank is released, and then cracks around the perforated hole grow into the surface, finally break-up may occur. However, the ballistic limit equations for curved plates have not been sufficiently investigated. the other is caused by fragments after perforation. After a perforation due to a debris impact, the fragment cloud is generated. The fragment cloud cause multiple cracks in the inner wall of the tank, and then break-up may occur by the cracks. In addition, since it is a hypervelocity impact phenomenon, the thermal energy of the fragments may contribute the explosion of the propellant. Therefore, it is also necessary to consider the energy of the fragments generated after perforation. The purpose of the study is to clarify the applicability of the ballistic limit equation of a flat plate to a curved plate and to obtain the energy distribution of the fragments after perforation of both plates. Hypervelocity impact tests were conducted on curved titanium alloy plates cut from a propellant tank and flat plates made of the same material. And it was also conducted on aluminum alloy plates. The projectiles were aluminum balls in diameters of 0.5 and 1.0 mm, and the impact velocities were 3-7 km/s. As a result, it was found that the ballistic limit equation for the flat plate can be applied to a curved alloy plate with a radius of curvature of about 25 mm for prediction of ballistic limit. After the tests, craters on the witness plate behind the plate were measured. In the case of the curved plate, the craters which have a diameter of >0.2 mm and a depth of >65.4 μm. were observed only inside of 60 mm from the center.

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