並列タイトル等Fracture and Fatigue Characteristics of Metals for LOX/LH2 Rocket Tank Structure Tested at 4K, 77K and Room Temperature
タイトル（掲載誌）航空宇宙技術研究所報告 = Technical Report of National Aerospace Laboratory TR-619
一般注記出版タイプ： NA
In connection with the development of rocket tank structure containing cryogenic liquid propellant, mechanical properties and fracture toughness were examined for several candidate metals of the structure in order to obtain the fundamental design data at 4K, 77K and room temperature. Materials tested in the present study were three kinds of aluminum alloy(2219-T87, 2014-T651, ZK141-T6) and one stainless steel(301-H). For each alloy, the strength of welded joint as well as the parent metal was colsely examined. Crack propagation behavior of 2219-T87 parent metal under low cycle fatigue loading at 4K was also reported in the paper. The effects of location and orientation of a crack, notch acuity and residual stress on fracture toughness were studied by using sheet specimens with a through-the-thickness crack or a surface crack. All test results were analysed by the technique of the linear fracture mechanics theory. It was observed that the fracture toughness of welded joint and parent metals of 2219-T87 and ZK141-T6 consistently increases or remains constant as the testing temperature is decreased, regardless of the location or orientation of a crack. In terms of the other two alloys tested, no consistent trend of fracture toughness with testing temperature was observed. It was shown that the strength of the panels with various sizes of cracks can be successfully presented using a modified residual strength diagram, which was originally proposed by Feddersen. On low cycle fatigue testing conducted at 4K, crack extension, which was not possible to observe directly as the specimen was enclosed in a cryostat, could be measured by tracing crack opening diaplacement(COD) at each loading cycle. In order to calculate crack length analytically from measured COD, a work-hardening crack model was employed, which gave quantitatively good agreement with the actual crack length. The testing results lead to the following relation for the crack propagation rate of the 2219-T87 parent metal: da/dn=4.8×10(exp -13)ΔK5.1
資料番号: NALTR0619000
レポート番号: NAL TR-619
連携機関・データベース国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）
提供元機関・データベース宇宙航空研究開発機構 : 宇宙航空研究開発機構リポジトリ