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Since the last decade, the automotive industry has expressed the need to better understand how the different trim parts interact together in a complete car up to 400 Hz for structureborne excitations. Classical FE methods in which the acoustic trim is represented as non-structural masses (NSM) and high damping or surface absorbers on the acoustic cavity can only be used at lower frequencies and do not provide insights into the interactions of the acoustic trims with the structure and the acoustic volume. It was demonstrated in several papers that modelling the acoustic components using the poroelastic finite element method (PEM) can yield accurate vibro-acoustic response such as transmission loss of a car component [1,2,3]. The increase of performance of today's computers and the further optimization of commercial simulation codes allow computations on full vehicle level [4,5,6] with adequate accuracy and computation times, which is essential for a car OEM.

Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities. The main physical mechanisms related to noise generation within a turbulent flow and the vibro-acoustic transmission through the vehicle greenhouse is nowadays better understood. Several simulation methods such as CFD, FEM, BEM, FE/SEA Coupled and SEA can be coupled together to represent the physical phenomena involved. The main objective being to properly represent the convective and acoustic component within the turbulent flow to ensure proper computation of the wind noise contribution to the interior SPL of a vehicle.

It is well known today that Biot parameters are the intrinsic material properties of porous media such as foams and fibers. They are to porous media what Young’s modulus is to steel panels. Once these Biot parameters are accurately known, one can trust that a predictive simulation model will yield the corresponding level of accuracy. But how accurate must these Biot parameters be to warrant a safe level of accuracy of the resulting simulation models? This paper analyzes various round-robin tests publications related to measurements of Biot parameters (acoustic and elastic) and uses the reproducibility of measured data from the numerous laboratories involved to evaluate the effect of the observed measured variability on simulation models accuracy when predicting transmission loss, surface absorption and actual sound pressure level (SPL) response inside a vehicle.