2021 Fiscal Year Final Research Report
Dynamic characteristic measurement and damage detection of integrated machine/building/infrastructure systems via laser-induced plasma excitation
| Project/Area Number |
19H02088
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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 20010:Mechanics and mechatronics-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | レーザー / 振動計測 / ヘルスモニタリング / 損傷検知 / インパルス応答 |
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| Outline of Final Research Achievements |
A monitoring system for concrete hardening using laser excitation/measurement was developed in this study. Aluminum (Al) beam inserted in mortar was used as measurement object. Laser beam was irradiated to the Al beam to excite the vibration due to laser ablation and its frequency spectra were measured. It was confirmed that the characteristics on the resonance frequency and damping of the Al beam change as the mortar hardens over time. Moreover, it was found by the finite element analysis that there is a relationship between the hardness of the mortar and the natural frequency of the Al beam inserted in the mortar. By comparing the theoretically calculated frequency with the experimental result, the elastic modulus of the mortar and its variation with time could be estimated. The effectiveness of the developed monitoring system for concrete hardening was verified by some experiments.
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| Free Research Field |
レーザー応用技術，機械力学，制御工学
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| Academic Significance and Societal Importance of the Research Achievements |
インフラ構造を支えるコンクリートに関し，その強度特性を十分に発揮するには，コンクリートの時間経過による特性変化をよく把握した適切な施工が必要である．一方，その複雑な特性から，技術者の経験に頼らざるを得ない状況があり，システム化に基づく定量的評価が要求されている．本研究では，レーザーを用いた非接触加振／計測技術によりコンクリートの硬化モニタリングを行う手法・技術を構築した．本手法・技術の実用化が実現すれば，構造物の特性評価およびメンテナンスの高効率化が図られるとともに，構造物の信頼性向上に大きく貢献することから，大きな学術的意義および社会的意義を有する．
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