Equivalent curvatures broadband Insertion Loss simulation technique coupling Virtual SEA and BEM/FEM approaches

摘要

Reliable broadband trims simulation is a key issue in the automotive industry, in order to reach CO_2 emission reduction targets, meaning reducing weight while maintaining the passenger's acoustic comfort. Recent developments have shown the feasibility to use BEM/FEM approaches in the low-middle frequency range for both trims considered alone (dash-inner or complete floor for example) or in combination such as the so-called cockpit (dash-inner and instrument panel) for example. Nevertheless, such kind of modeling approaches remain time-consuming especially regarding multilayers trims meshing tasks. Using a frequency dependent SEA substructuration based on a virtual Power Injection Method and a peripheral attraction algorithm (Virtual-SEA analysis) for the bare structure, the aim here is to introduce trims as FEM Insertion Losses recomposed from a database of pre-computed equivalent curvature cases (depending on radius of curvature, thicknesses and nature of the trim) in order to drastically decrease the model building time and thus automate computation tasks. This paper presents direct measurement of a dash-inner in coupled reverberant rooms and the correlation with the full direct BEM/FEM simulation and the correlation with this new equivalent curvature approach depending on the way the trim Insertion Losses are simulated: FTMM on plane models and/or BEM/FEM techniques on plane and curved models.