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Advances in Acoustics and Vibration
Volume 2008, Article ID 603084, 9 pages
http://dx.doi.org/10.1155/2008/603084
Research Article

Improvement of Transmission Loss Using Active Control with Virtual Modal Mass

1LaMCoS, INSA-Lyon, CNRS UMR5259, F69621, France
2LVA, INSA-Lyon, F69621, France

Received 16 January 2008; Revised 1 April 2008; Accepted 19 May 2008

Academic Editor: Marek Pawelczyk

Copyright © 2008 V. Lhuillier et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper deals with an alternative modal active control approach to reduce sound transmission through a structure excited by an acoustic wave. Active control makes it possible to conserve lightness while improving acoustic performances. “Modal mass damping control” is proposed for light and small structures having slight modal overlap. The aim of this control is to modify the modal distribution of high radiation efficiency modes with active modal virtual mass and active modal damping. The active virtual mass effects lower eigen frequencies to less audible frequency range while reducing vibration amplitudes in a broad frequency range. An application of this concept is presented in a simple smart structure. It is harmonically excited on large bandwidth by a normal acoustic plane wave. Results obtained by active modal virtual mass and damping control are compared to other modal control approaches.