Equivalent damping added by Sound package

In Automotive and Aerospace industries, sound package has an important role to help identify and control vehicle noise in order to improve passenger comfort and reduce environmental noise pollution. The well-known used approaches to model the sound package are Transfer Matrix Method (TMM) combined with Statistical Energy Analysis (SEA). The effect of sound package on the sound radiation can be summarized in three points. (i) Interact with the non-resonant response of the panel to modify the mass law. (ii) Act as a barrier and modify the radiation efficiency of the panel. (iii) Acts as a multilayer damping treatment on the panel. To the best of our knowledge, the equivalent damping due to the multilayer has not been done by earlier researchers and it's a novel approach. In this paper, an experimental study will be conducted to assess the add-on damping by sound package for different configurations. The decay rate method will be used to measure the damping indicator on a flat samples attached to acoustic treatments. Different parameters will be investigated such as: Nature of the foam, thickness, boundary conditions (bounded or no bounded to the master structure) etc.