2001 Fiscal Year Final Research Report Summary
Determination of Required Quality and Quality Control by Ultrasonic Testing of Welded.joints for Steel Bridges
| Project/Area Number |
11305034
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
構造工学・地震工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MIKI Chitoshi Tokyo Inst. of Tech. , Grad. School of Civil Eng., Prof., 大学院・理工学研究科, 教授 (20016645)
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| Co-Investigator(Kenkyū-buntansha) |
HIROSE Soichi Tokyo Inst. of Tech. , Grad. School of Civil Eng., Prof., 大学院・情報理工学研究科, 教授 (00156712)
MORI Takeshi Hosei Univ., Faculty of Eng., Prof., 工学部, 教授 (10157860)
ICHIKAWA Atsushi Tokyo Inst. of Tech. , Grad. School of Civil Eng., Prof., 大学院・理工学研究科, 教授
MURATA Kiyomitu Railway Technical Research Inst. , Civil Eng. Div., Manager, 技術開発事業本部, 主幹技師
NISHIKAWA Kazuhiro Ministry of Land, Infrastructure and Transport, National Inst. of Land and Infrastructure Management, Investigater, 国土技術政策総合研究所, 評価研究官
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| Project Period (FY) |
1999 – 2001
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| Keywords | welded joint / weld defect / allowable defect size / fatigue performance / fracture mechanics / ultrasonic testing / acoustical anisotoropy |
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| Research Abstract |
The summary of this study is as follows.
1) The fatigue performance of butt welded joints containing various embedded defects was investigated by tatigue tests and it became clear that the fatigue strength depends on the type of defects.
2) Based on the fatigue tests and the present level of non-destructive testing, as the allowable defect size, one sixth of plate thickness was suggested.
3) The round robin test of existing automatic ultrasonic testing systems was carried out and as a result, it was made to be clear that welded defects in 40mm or thinner steel plates can be detected by all the tested systems, but that those in 100mm plates cannot be detected by some systems.
4) The existence of anisotoropy in thickness direction of steel plates was shown and it was made to be clear by experiments and wave propagation simulation by finite element method that it can affect the determination of the location of defects in ultrasonic testing.
5) The existence of anisotoropy in thickness direction of steel plates was shown and it was made to be clear by experiments and wave propagation simulation by finite element method that it can affect the determination of the location of defects in ultrasonic testing.
6) For the purpose of more accurate quantitative evaluation in ultrasonic testing, tandem array transducer was proposed and the applicability was shown. And it was shown that by utilizing the transducer, the difference between fatigue cracks and weld defects can be recognized by evaluating the characteristic of fatigue crack closure.
7) As for fracture toughness, which is one of the most important factor for the quality of welded joints, it was shown by Charpy Impact Testing for base metal that in case that steel plates experience the plastic strain history, it can be deteriorated, but the extent of the deterioration doesn't depend on the direction of plastic strain or notch.
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