Acoustic Modeling of a 3-Layered Panel Incorporating Electro-Rheological/ Magneto-Rheological (EMR) Fluids

Abstract

Applications of Electro-Rheological (ER) or Magneto-Rheological (MR) fluids as typical smart ma terials have been widely investigated over the past decades (since their introduction in 40 ’ s). The special application s of these materials as a means of noise suppression are not yet investigated. Constrained Layer Damping (CLD) sheets can be realized by incorporating EMR (ER/MR) materials. In this way, a multilayered damping sheet is obtained with adaptive (tunable) stiffness and damp ing characteristics. These properties are easily changed in proportion to the electric (magnetic) field applied upon the EMR layer. This notion has been introduced for semi-active vibration con trol problems. Herein, such panels incorporating EMR material are proposed for adaptive acoustic treatment s . Modeling (simulation) of a 3-layered panel with the middle layer being EMR with ad justable properties is carried out in this paper. The tunability of transmission/absorption charac teristics of these composite sheets enables us making smart panels for adaptive noise and acoustic treatments. An adaptive performance can be achieved via changing the properties of such panels, on line, according to some sensor outputs. The main objective is to develop proper models to pre dict the Transmission Loss (TL) of such panels. Also, the TL of this panel is compared with the middle layer of a Newtonian fluid.