宇宙機構造壁の曲率がデブリ衝突損傷に与える影響

• Published in: 構造物の安全性および信頼性：構造物の安全性・信頼性に関する国内シンポジウム(JCOSSAR)論文集 pp. 219 - 224
• Main Authors: 東出, 真澄, 足立, 寛弥, 鈴木, 清花, 池田, 博英, 長田, 泰一, 仁田, 工美
• Format: Journal Article
• Language: Japanese
• Published: 構造物の安全性・信頼性に関する国内シンポジウム運営委員会 2023
• Subjects: Curvature; Hypervelocity impact; Pressurized vessel; Space debris
• ISSN: 2759-0909
• DOI: 10.60316/jcossar.10.0_219

This study focuses on space debris impact risk of pressurized vessels installed in spacecrafts. Wall perforation conditions are necessary to assess the debris impact risk of the pressurized vessel. Ballistic limit equations are generally used to know the debris impact conditions causing perforation of the structure wall. However, these equations have almost been developed for flat plates. The purpose of this study is to investigate effects of curvature of the structure wall to debris impact damage. Hypervelocity impact experiments were conducted to both of flat and curved plates. Titanium alloy plates of 1.2 mm in thickness and aluminum alloy plates of 3.0 mm in thickness were tested. The radiuses of curvature were approximately 210 mm of titanium and approximately 50 mm of aluminum. The experimental results were compared with NASA’s ballistic limit equation for metallic flat plates. As a result, the equation was able to predict not only flat plate results but also curved plate results. The peeling fracture by spalling was only observed on the backside of the titanium curved plate. In aluminum plate results, the differences of damage were not seen by the curvature. It seems that the effect of the curvature is difficult to appear for ductile material. The numerical simulations were also performed with the same condition as the impact experiments. The simulation results showed in good agreements with the experimental results. To investigate distributions of fragments generated by the perforated experiments, the numerical simulations with the SPH method were performed. The spray angle of the fragment cloud became smaller by the curvature. In the experiments, the fragment distributions were obtained from crater examination of witness plates installed behind the targets. The spray angle decreased by approximately 10 degrees due to the curvature of the target.