During the design phase of a vehicle, it is important to have a simulation tool, which allows to make multiple runs and check the sensitivity of the acoustic response to several trim configurations with a quick turnover time.
The Statistical Energy Analysis (SEA) is widely used to investigate such problems for airborne excitation. For structure-borne excitation, classical methods based on a simplistic modeling of the trim using 1D oscillators and non-structural mass are not accurate enough to capture the actual behavior of the trim. On the other hand, a detailed Finite Element-Poroelastic Element Method (FE-PEM) modeling strategy of the trim may be time consuming. Besides the large number of degrees of freedom required to accurately model dissipative materials (e.g. poroelastic), a FE-based approach also needs a preprocessing phase where each layer of the trims must be carefully meshed. This task can be time consuming when the response of several configurations of the same system must be simulated, like, for instance, in an optimization process.
In this paper, two alternative strategies based on the Transfer Matrix Method (TMM) are proposed to evaluate the surface impedance of the trim. This impedance can be applied to the FEM model of the bare vehicle and allow a first design change analysis before a more detailed concept validation done using FE-PEM.
The method will be demonstrated on industrial example.