| Project/Area Number |
11650098
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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 |
Materials/Mechanics of materials
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| Research Institution | TOHOKU GAKUIN UNIVERSITY |
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Principal Investigator |
ENDOH Haruo Tohoku Gakuin University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (20137582)
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| Co-Investigator(Kenkyū-buntansha) |
HOSHIMIYA Tsutomu Tohoku Gakuin University, Faculty of Engineering, Professor, 工学部, 教授 (40118336)
HIWATASHI Yoichiro Tohoku Gakuin University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (30048813)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Photoacoustic Microscopy / Photoacoustic Imaging / Surface-subsurface Combined Defect / Branched Complicated Defect / Internal defect / NDT / 枝分かれ欠陥 / 江音響影像 |
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| Research Abstract |
In the present work, The imaging of the simulated surface-subsurface combined defect using photoacoustic microscope (PAM) has been demonstrated. Two types of complicated defects are prepared. Simulated surface and subsurface defects geometry of one type are fabricated independently such that the former was grilled on a pure aluminum plate whereas the latter was machined with end mill. Specimen with subsurface defect alone was also carried out. The photoacoustic image obtained clearly showed the location and the size of both subsurface defect and the surface-subsurface combined defect. The photoacoustic method is useful for detection of the combined defect which is difficult to detect with present NDE techniques. That of the other type are the simulated branched complicated defects. The surface vertical defect was fabricated on the metal specimen surface by mechanical processing to produce an accurate shape at the center of the specimen, and the surface defect depth is fixed to be 1.0 mm. The subsurface defect was made perpendicular to the surface defect. The shape of the subsurface defect was cylindrical, and the length was fixed to be about 2.0 mm. The distance from the specimen surface to the center of the subsurface defect was 0.3 and 0.5 mm. In conclusion, the surface defect and the subsurface defect were distinguishable in the PA amplitude image obtained by the PAM when the modulation frequency was changed so that the thermal diffusion length was scanned in the vicinity of the depth of the buried undersurface part of the specimen. The size of the undersurface part of the combined defect was obtained.
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