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A poroelastic material can be represented as a material that is constituted by two phases: a structural phase given by a solid frame, and a fluid phase given by the air that fills the pores of the solid frame itself. In the mid frequency range, the physical behavior of both phases and their interactions need to be properly modeled in order to predict accurately the dynamic behavior of the porous material. This can be done using finite elements based on Biot's theory, which describes the macroscopic behavior of poroelastic materials by characterizing them through a set of parameters directly measured on material samples. In this paper, numerical/experimental correlations obtained using two commercial software programs that implement libraries of poroelastic materials are presented. A free-free steel plate covered by a 20mm thick layer of foam and a massive heavy layer has been selected as a first test case.

A prediction tool based on the transfer matrix approach is applied for calculating the effects of the sound package on acoustic cavities damping and on trimmed panels coupling loss factors, needed for SEA modelling of vehicles. Predicted TL and absorption of trimmed components are compared to measurement results. The tool allows calculating, outside the SEA software, the needed quantities for multi-layered insulation components, by taking into account also the non-uniformity of the insulation part and of the structure. This feature is crucial, especially in all cases, in which SEA models are used to design and optimise the vehicle acoustic package.

This paper describes an effective method of developing a soundproof package, which balances both light weight and high noise insulation performance. Since it is required to propose design of sound insulator in the early stages of the development, the hybrid statistical energy analysis (SEA) modeling method is applied, which is practical for high frequency analysis. Also an acoustic characteristic estimation technique of the multi layer structures is used. As a result of applying these effective methods, the 2006 brand-new vehicle categorized as C has enhanced in road noise quietness and decreased in weight as compared with the previous model.