| Project/Area Number |
22K20444
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
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| Research Institution | Gifu University |
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Principal Investigator |
Banno Yuki 岐阜大学, 工学部, 助教 (90966194)
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| Project Period (FY) |
2022-08-31 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2023: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | ピーニング・HFMI / 疲労き裂 / 溶接継手 / 塑性流動 / ピーニング・HFMI処理 / 閉口き裂の再閉口挙動 / 3次元き裂進展解析 |
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| Outline of Research at the Start |
2009年以降，我が国では鋼橋の溶接部に生じた疲労き裂の効率的かつ合理的な新しい延命化手法として，疲労き裂表面をピーニング・HFMI処理に伴う塑性流動により閉口させる技術開発が，申請者の研究を含め精力的に進められてきた．申請者は，閉口された疲労き裂の再開口プロセスの全容解明を目指し，閉口された疲労き裂が閉口部の最深部から再開口することを実験・解析的に明らかとしている．その上で，本研究は，ピーニング・HFMI処理によりき裂面に導入される圧縮残留応力に加えて，塑性流動も考慮可能な3次元き裂進展解析手法を開発し，最深部から表面に至るまでの閉口部の再開口挙動の完全再現を目指す．
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| Outline of Final Research Achievements |
The goal of this study is to develop a numerical analysis method to reproduce crack opening behavior of closed crack by peening treatment by coupling 3D crack propagation analysis considering plastic flow. To achieve this goal, to clarify the plastic flow acting on the crack surface closed by crack closure retrofit treatment using peening treatment, a cracked welds was peened, and crack surface was closed, and the plastic flow acting on the crack closure surface was observed using a metallurgical microscope. The results showed that a crack was closed by the plastic flow caused in the metallographic structure due to plastic deformation by the crack closure retrofit treatment.
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| Academic Significance and Societal Importance of the Research Achievements |
本成果は，閉口処理後のき裂面に作用する塑性流動を電子顕微鏡観察により明らかとした．これは，ピーニング・HFMI処理を用いたき裂閉口による延命化手法の信頼性向上に繋がることから，高齢化のよる疲労損傷が著しい我が国の鋼橋の維持管理において社会的意義のある成果であると考える．また，この成果は，き裂閉口メカニズムおよび閉口処理後のき裂の再開口挙動の解明に繋がる学術的意義のある成果と考える．
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