| Project/Area Number |
18K03850
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
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| Research Institution | Shonan Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 水素脆化 / 過大荷重 / 数値解析 / 疲労強度 / 水素濃度予測 / 疲労 / 水素濃度分布 / 材料強度 |
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| Outline of Final Research Achievements |
In this study, the effect of the overload history on hydrogen embrittlement mechanism under fatigue conditions was clarified by numerical analyses and fatigue tests of hydrogen charged specimen. The following results were obtained.
1) The numerical analysis for the effect of the overload history on hydrogen diffusion and concentration behavior under cyclic loading condition was conducted. From this analysis, it was indicated that there are some conditions that hydrogen concentration is promoted by overloading. The hydrogen concentration capability was estimated by the triaxial factor, and the hydrogen concentration estimation formula was proposed.
2) The fatigue test method with overload to hydrogen charged specimen was established and tested. Acceleration of crack growth rate couldn't be observed, but a crack growth path changed. From these results it was suggested that sensitivity to hydrogen embrittlement under fatigue conditions depended on overload.
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| Academic Significance and Societal Importance of the Research Achievements |
水素エネルギー社会の実現に向けて，水素ガスの貯蔵設備には安価で安全な構造設計が必要とされる。一方で，比較的安価で高強度である鋼は水素脆化するが，材料中の水素濃度が上昇する条件を明らかにして水素脆化を未然に防ぐことは非常に重要である。他方，大気中の疲労では過大荷重が悪影響を与えないと考えられているが，水素雰囲気の場合については研究されていない。
本研究の成果は，単純な疲労条件の水素脆化研究をさらに進めた独創的な研究であり，水素凝集に対する過大荷重の効果を示した重要な知見を得た。社会的には，地震や衝撃など想定外の荷重が加わった後の水素脆化を予測して安全性を確保するために必要な基礎的な知見と言える。
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