| Project/Area Number |
14550084
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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 | Osaka City University |
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Principal Investigator |
YAMASAKI Tomohiro Osaka City University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (80230382)
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| Co-Investigator(Kenkyū-buntansha) |
MOTOGI Shinya Osaka City University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (40221626)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2003: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2002: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | GFRP / Delamination / Nondestructive inspection / Lamb wave / Electromagnetic acoustic transducer / Damage evaluation |
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| Research Abstract |
Electromagnetic acoustic transducers(EMATs) were applied to detection of delamination in glass fiber reinforced plastic(GFRP) laminates. Since velocity of Lamb wave shows the dependence on the plate thickness, we proposed to evaluate the delamination by detecting the fractional change in the Lamb wave velocity. The EMATs, each of which consists of a coil embedded in the laminate and a permanent magnet put on the laminate, were used to launch and receive the Lamb wave. We measured both phase and group velocities.
In the group velocity measurement, short pulse excited the transmitter EMAT. Then, the amplitude of the center frequency component of the received signal was calculated in the time domain. Time of the peak amplitude was plotted against the path length, and we could evaluate the delaminated section as the region of the slightly lowered slope. We found that the position of the Delamination front can be evaluated with an accuracy of 10mm in the 12 ply laminate.
In order to measure the phase velocity, we used the meander line coil EMAT. When the half wavelength of the Lamb wave coincides with the coil pitch, the amplitude of the received signal takes the maximum value. We revealed that the delamination at the receiving position can be detected successfully in the 32 ply laminate.
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