1996 Fiscal Year Final Research Report Summary
Structural Intensity Measurement by Two-dimensional Wave Decomposition
| Project/Area Number |
07555633
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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 | 試験 |
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| Research Field |
Dynamics/Control
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| Research Institution | Tohoku University |
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Principal Investigator |
KATO Masana Tohoku University, Faculty of Engineering, Professor, 工学部, 教授 (60005262)
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| Co-Investigator(Kenkyū-buntansha) |
MAEHARA Osamu Ono Sokki Co., Ltd., Sensor & Applications Div., General Manager, センサ応用事業部, 部長
MASUYAMA Tomoya Tohoku University, Faculty of Engineering, Associate, 工学部, 助手 (80282094)
DENG Gang Tohoku University, Faculty of Engineering, Associate, 工学部, 助手 (90237040)
SHIBATA Katsuhisa Tohoku University, Faculty of Engineering, Associate, 工学部, 助手 (20196421)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Structural intensity / Laser Doppler vibrometer |
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| Research Abstract |
Wave composition mehtod is proposed as a measurement method to obtain the structural intensity for a thin plate. Its concept is tranforming vibration displacement only in neighborhood of evaluating point of structural intensity by Fourier transformation. Measurement points can be located on the circle coinciding its center with the evaluating point. The number of measurement points is arbitrary.
Simulations of measurement accuracy for basic vibration field are performed. While accuracy is better with the decrement of measurement diameter without measurement errors at sensors, taking account of error unavoidable in real measurement, larger value of measurement diameter is desirable. This manner is similar to that of finite difference, but the frequency range achieving good accuracy is broader, and this method is robust compared with finite difference method.
Laser Doppler vibrometer is employed in measurement. Sensorhead rotation unit is developed and intensity is evaluated in basic field. Laser beam is inclined to the axis of rotation, not offset. Evaluated input power shows good coincidence with measured input power, it demonstrates the validity of this method. Ignoring near field terms, putting the number of measurement points equal to the number of waves for composion, the number n is not sufficient for four, sufficient for more than six. Sensor rotation unit is small enough to mount on a tripod, large and complicated XY table or robot is not required for measurement, the limitation of size of measurement object. It is concluded that this method is very applicative.
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