2018 Fiscal Year Final Research Report
Research on defect and bolt fastening looseness detection technology using stress stethoscope for aging social infrastructure
| Project/Area Number |
16K01301
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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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| Research Field |
Social systems engineering/Safety system
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| Research Institution | Tokyo National College of Technology |
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Principal Investigator |
Shimura Jyo 東京工業高等専門学校, 機械工学科, 准教授 (70390424)
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| Co-Investigator(Kenkyū-buntansha) |
林 丈晴 山梨大学, 大学院総合研究部, 准教授 (70637264)
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| Research Collaborator |
KUROSAKI Shigeru
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 材料欠陥 / ボルト緩み / 応力聴診器 / 打撃加振 / ひずみ分布 / 動ひずみ / 軸力 / 減衰率 |
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| Outline of Final Research Achievements |
The purpose of this study is to examine the detection of defects in structural materials and looseness of bolted joints using a stress stethoscope. An attempt was made to detect defects by repeatedly applying a load to a flat plate specimen with a notch as an artificial defect and measuring the strain distribution near the notch with a stress stethoscope. In addition, dynamic strain measurement was performed using impact vibration and a stress stethoscope to detect looseness of bolted joints, and the correlation between bolt axial force and strain time fluctuation was investigated. The former strain measurement experiment suggested the possibility of defect detection by finding the maximum strain occurrence point in the strain distribution. In dynamic strain measurement experiments, it was shown that the bolt looseness could be detected from the increase or decrease of the damping factor of the dynamic strain waveform.
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| Free Research Field |
材料力学
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| Academic Significance and Societal Importance of the Research Achievements |
応力聴診器を用いた構造部材の欠陥及びボルト締結の緩み検出技術は，低コストかつ簡易性を有する新たな非破壊検査手法として位置付けられ，主として国内の老朽化した橋梁構造物の保全・改修に役立てることができる．また，土木分野に限らず，機械及び建築分野でも本技術が適用可能であり将来性・発展性を期待できる．
本研究成果はまだ実験室レベルのものであるが，様々な条件下での実験結果を蓄積し知見を深めることで，将来的には現場での使用が可能になると推察している．これにより，喫緊の問題である老朽化社会インフラの健全性を評価する技術として重宝されると考えている．
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