| Project/Area Number |
18H01524
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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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| Review Section |
Basic Section 22020:Structure engineering and earthquake engineering-related
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| Research Institution | Ehime University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
森 伸一郎 愛媛大学, 理工学研究科(工学系), 准教授 (10304643)
高橋 学 愛媛大学, 社会共創学部, 教授 (20274334)
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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 |
¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000)
Fiscal Year 2020: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2019: ¥8,580,000 (Direct Cost: ¥6,600,000、Indirect Cost: ¥1,980,000)
Fiscal Year 2018: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
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| Keywords | 閉口き裂 / 振動 / 超音波 / 和差調波共振 / 固有振動数 / コンクリート / 非破壊検査 / 波形ひずみ / 非線形音響 |
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| Outline of Final Research Achievements |
The purpose of this study is to develop a quantitative nondestructive evaluation method of closed clacks in a structural component using the interaction of sound and vibration. This method utilizes a nonlinearity due to contact and separation behaviors of a clack face.
First, we investigated the ultrasonic transmission waveforms in the case of contacted and separated conditions of the clack face experimentally and numerically. Then, the summed and differential harmonics by the clack face interaction were measured in a steady-state using oscillation sources with two different frequencies. The next step is to measure the nonlinearity using ultrasonic transducers. Furthermore, we succeeded in ultrasonic imaging using a low-frequency array transducer designed for the concrete structure. As future works, we combine nonlinear ultrasonics to array imaging and validate it for actual cracks.
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| Academic Significance and Societal Importance of the Research Achievements |
き裂が閉じている場合は，非破壊検査時において過小評価する場合が多く，閉じたき裂の定量的評価は社会インフラの維持管理の高度化において悲願であった．本研究の独創的な点は，き裂界面の開閉口に起因する振動の非線形現象を超音波で計測することである．この非線形現象を数理モデルに基づいて説明し，さらにこれらの発生が顕著になる条件を明らかにできたことは学術的にも有意義である．き裂界面の非線形現象の発現について基礎的知見を得ることができたので，今後は，実用に向けたセンシング法を構築することが課題である．
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