The Study on the Aoustic Radiation Control of Plate by using Magnetism-Induced Forces
Date Issued
2006
Date
2006
Author(s)
Ou, Cheng-Chian
DOI
zh-TW
Abstract
This is mainly to study magnetic control on the acoustic radiation from a plate clamped at edges by a force at resonant frequency.Regarding the magnetic control experiment involved,a PZT is used as the required actuator,an electromagnet and a magnet are used to be the controller.The possessive position is decided by using mathematical model,we can choose these previous four basic vibration mode near the anti-node, by using the strong magnetism, we control the acoustic power radiation at low resonant frequencies firstly, then discuss about responding at high resonant frequencies furthermore and hope it can be fulfilled to reach the expectation effects.
The results as obtained shows more than 20dB attenuation of acoustic power radiation at all of low resonant frequencies (183、285、346、429Hz) besides the frequency in 285Hz. When we measure the acoustic power radiation for high resonant frequencies (546、583、643、790、810、894、1006、1048、1126、1216Hz),it not only can be attenuated more than 20dB of acoustic power radiation at 546、810Hz,but also can be attenuated more than 10dB of acoustic power radiation at 894、1048、1126、1216Hz,in other high resonant frequencies ,the possessive position not always comply to the vibration mode ,which it caused less effectively result from the control process.
The experimental results show if we can choose the appropriate magnetism and position,so that the acoustic power radiation can be controlled at low resonant frequencies,but not absolutely at high resonant frequencies.
Subjects
平板
結構模態
電磁作用力
聲音輻射
plate
electromagnet
radiation
mode
Type
thesis
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