1997 Fiscal Year Final Research Report Summary
Non-destructive investigation of a structure by vibration analysis
| Project/Area Number |
08650475
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
計測・制御工学
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| Research Institution | lwate University |
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Principal Investigator |
ABE Masato Iwate University, Faculty of Engineering, Professor, 工学部, 教授 (00159443)
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| Co-Investigator(Kenkyū-buntansha) |
MIWA Jouji Iwate University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60125664)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Defect investigation / Structure / Surface wave / Beamforming / 音波検査 |
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| Research Abstract |
We have developed a method to estimate the position of defects of a structure by vibration analysis. We used a concrete block as the structure and the defect is modeled by a vinyl sheet with a thickness of 200 mum. An array of sensors is attached on the surface of the concrete block, and a vibration pulse is forced using a small hammer. Since the forced vibration reflects at the position of a crack, the position will be estimated by picking up the reflection wave with an array of sensor using a beamforming technique. Since the power of the surface wave is much greater than that of the necessary reflection wave from the defect, the position of the defect could not been estimated correctly. So, we have developed a method to eliminate the useless surface wave, and a better estimation was achieved. But this method requires the restriction that a crack should be parallel to the surface. To avoid this restriction, we newly assume that the forced vibration reflects at the position of a crack and spherical wave is radiated to the sensors. Some experiments were carried out, and good results were obtained in the case that crack was slanting to the surface of the block.
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