CHANG Daoqing LIU Bilong LI Xiaodong TIAN Jing

(Key Laboratory of Noise and Vibration Research, Institute of Acoustics, Chinese Academy of Sciences  Beijing 100190)

Received Nov. 20, 2008

Revised Jan. 20, 2009

Abstract The feasibility of sound absorbing by a vibrating plate with piezoelectric material and shunt circuits is theoretically investigated. Based on an equivalent compliance of a piezoelectric wafer shunted with RL circuits, the governing equations for the flexural vibration of the plate with the piezoelectric wafer are derived using Lagrange’s approach. The equations take into account not only the mass, stiffness and structural damping of the plate and the wafer, but also the electrical resistance and electrical inductance of the RL circuits. By using the governing equations derived, the surface impedance and sound absorption coefficient of the plate backed with a cavity are given. Numerical results show that the sound absorption coefficient of the plate near its first mode can be significantly improved by adjusting the RL parameter. 　

PACS numbers: 43.50