1997 Fiscal Year Final Research Report Summary
Development of Identification Method of Defects Embedded in a Body by A.C.Electromagnetic CT Method Using Inverse Analysis of Frequency Response
| Project/Area Number |
07555349
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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 | 展開研究 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Osaka University |
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Principal Investigator |
KUBO Shiro Osaka University, Faculty of Engineering, Professor, 工学部, 教授 (20107139)
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| Co-Investigator(Kenkyū-buntansha) |
IOKA Seiji Osaka University, Faculty of Engineering, Research Associate, 工学部, 助手 (50283726)
SAKAGAMI Takahide Osaka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50192589)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Non-destructive Testing / A.C.Electric Potential Method / Crack / CT Method / Inverse Problem / Fracture Mechanics / Boundary Element Method / Electromagnetic Field Analysis |
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| Research Abstract |
The present investigators proposed the D.C.electric potential CT (computed tomography) method for identification of two- and three- dimensional cracks embedded in an electric conductive body. The usefulness of the method was shown by numerical simulations and experiments. In this study, by extending the D.C.electric potential CT (computed tomography) method, A.C.electric potential CT defect identification method was proposed, in which electric potential distribution for several A.C.frequencies were used to identify the crack. The main conclusions obtained are summarized in the followings.
1. Electromagnetic field of cracked body was analyzed using boundary element method to construct calibration relation between A.C.potential and crack length.
2. A.C.electric potential distributions were measured for a body with a through crack. It was found that the calibration relation worked well.
3. The electric potential distribution was calculated, in the case that the frequency was high and the skin effect was significant.
4. Electric potential distribution in a three-dimensional surface crack was measured. It was found the electric potential distributions in the limits of high and low frequencies may be effective to identify the crack.
5. Crack identification was made using full three-dimensional electromagnetic field analysis. It was found that the method was useful.
6. For the identification of plural cracks fusion type genetic algorithm was proposed.
7. Identifiction of interface crack in dissimilar materials was made by extending the method. Nemerical simulations and experiments showed the usefulness of the method.
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