| Project/Area Number |
06452138
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied physics, general
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
UEHA Sadayuki Tokyo Inst.of Tech., Precision and Intelligence Lab., Professor, 精密工学研究所, 教授 (90016551)
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| Co-Investigator(Kenkyū-buntansha) |
FUJITA Hajime Tokyo Inst.of Tehc., Precision and Inteligence Lab., Visited Professor, 精密工学研究所, 客員教授 (40251673)
KOIKE Yoshikazu Tokyo Inst.of Tehc., Precision and Intteligence Lab., Research Associate, 精密工学研究所, 助手 (30251672)
NAKAMURA Kentaro Tokyo Inst.of Tech., Precision and Intteligence Lab., Associate Professor, 大学院・総合理工学研究科, 講師 (20242315)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 1995: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1994: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | structural intensity / structural borne wave / spatial Fourier transofrm / k-space / k-space filter / flexural vibration / ultrasonic Doppler effect / optical vibration measurement / 空間フィルタ / 振動放射音 |
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| Research Abstract |
The Purpose of this research is to establish the practical technique of structural intensity measurement. In this study, the k-space signal processing and ultrasonic Doppler vibrometer array for structural intensity measurement have been proposed. We have obtained the following results.
1.K-space method The derivation of structural intensity defined as vibration energy flow in solid structure contains the higher order spatial derivatives of displacement for flexural vibration. This calculation has a large effect on the measurement accuracy. In the proposed method, there are some merits that the spatial derivatives can be estimated only by the simple arithmetic in k-space using spatial Fourier transformation and that vibration noise can be reduced by k-space filtering. In order to avoid the loading effect on the specimen, a laser Doppler vibrometer was used which is one of the most promising candidates. We obtained the important result that the cutoff wave number for k-space filtering should be one and a half of the wave number of the measured vibration to minimize the influence of error in the measured data. This result was confirmed by the experiments for a beam and 2-dimensional plate.
2.Ultrasonic Doppler transducer array We proposed a new probe for structural intensity measurement using ultrasonic Doppler method. This probe is suitable to make a large array system, since the ultrasonic system is to easy handle and cheaper than the optical one and has no loading effect to specimens. The array probes for 1-dimensional and 2-dimensional measurements were made. The usable range of these array is 3 mm/s-1.0m/s at vibration frequency 1 kHz. The validity of the ultrasonic transducer array using Doppler effect is confirmed experimentally by the 1-dimensional and 2-dimensional structural intensity measurements.
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