Applications of Modal Analysis to Active Control of Sound by Plates
Date Issued
2004
Date
2004
Author(s)
Lin, Wen-Hong
DOI
zh-TW
Abstract
Active control of sound radiation from a vibrating clamped rectangular plate excited by a steady state harmonic PZT is experimentally studied.
First, the mechanism of vibrating plate is analyzed numerically. Then the sound power is calculated by summing individual contributions of radiation modes. From the numerical results, different locations of exciting points will have various radiation mode distribution patterns. Thus, it is possible to reduce more sound power by arranging the locations of controlling points to attenuate individual radiation modes.
For simplicity, the experiment of this study employs two independent control systems. The first one has a PZT attached to the corner of the plate with a piezoceramic patch as error sensor of vibration. And another PZT is attached to the center of the plate, with a microphone in the radiation field as error sensor of sound pressure. In recent researches, this arrangement of PZT at the center with microphone successfully reduces the sound power of first radiation mode. And the power of other modes can be attenuated by carefully choosing the location of piezoceramic patch error sensor.
The experiment results show that this control strategy reduces more sound power than a single control system in lower frequencies.
Subjects
模態分析
輻射模態
主動控制
Active Control
Radiation Mode
Moda Analysis
Type
thesis