2003 Fiscal Year Final Research Report Summary
NONDESTRUCTIVE EVALUATION OF MATERIAL DAMAGE WITH NONLINEAR ULTRASONIC CT
| Project/Area Number |
13450045
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Nagoya Institute of Technology |
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Principal Investigator |
KAWASHIMA Koichiro NAGOYA INSTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF ENGINNERING, PRPFESSOR, 工学研究科, 教授 (50023239)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Naoya NAGOYA INSTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF ENGINNERING, RESEARCH ASSOCIATE, 工学研究科, 助手 (60335099)
HAYASHI Takahiro NAGOYA INSTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF ENGINNERING, RESEARCH ASSOCIATE, 工学研究科, 助手 (30324479)
ITO Toshihiro NAGOYA INSTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF ENGINNERING, ASSOCIATE PROFESSOR, 工学研究科, 助教授 (20203151)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Nonlinear ultrasonics / Ultrasonic CT / Computed tomography / Harmonics / Material damage / Closed crack / Bonded interface / Signal processing |
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| Research Abstract |
The aim of this prqject is to establish an ultrasonic CT system with the second harmonic and to apply the system to evaluation and diagnosis of engineering material anomaly.
Main results in this project are summarized in the followings.
1) As a basis of nonlinear ultrasonic CT, an ultrasonic attenuation CT system has been developed in water immersion. By using a reference sample of known attenuation coefficient and the identical geometry with samples tested, the region of high attenuation coefficient in a steel block has been reconstructed by an ART algorithm. The reconstructed image of high attenuation region as well as the value of attenuation coefficient agree well the real ones. With proper penalty factors, we reconstructed drill holes of 2mm in diameter by ultrasonic attenuation CT.
2) With water immersion ultrasonic method, we succeeded to construct the second harmonic amplitude image with proper bandpass filters which reduce the fundamental wave amplitude. This second harmonic image are applied to nondestructive characterization of diffusion-bonded interfaces of different materials.
3)By combining the above two approach, we can construct nonlinear (the second harmonic) images of damaged solids, e.g., metals with micro cracks with gaps of nm order.
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