ABAV PhD and Young Acousticians Day edition:2 location:Liège, Belgium date:21 February 2014
Important parameters for the dynamic and acoustic behaviour of stiffened plates are the material properties, the geometry and the positioning of the stiffeners. Uncertainty on these parameters can have an important influence on the sound insulation. To reduce the uncertainty of sound insulation predictions performed with a Finite Element model of the stiffened plate, model updating is used to have an optimal agreement between the modelled and measured behaviour of the structure. A hybrid FE-SEA approach is employed, which has the advantage that the structure can be taken into account in detail by modelling it with Finite Elements (FE). On the other hand, by modelling the rooms with Statistical Energy Analysis (SEA), the method stays computationally efficient. The structure-borne and air-borne sound insulation of the stiffened plates can therefore be obtained accurately and efficiently. Also the variance of the predicted acoustic values due to the diffuse field assumption can be computed. A further advantage of the hybrid FE-SEA approach consists in that the coupling loss factors are computed automatically in a logical, consistent way, so that resonant and non-resonant transmission are automatically accounted for. The method is applied to a stiffened PMMA plate. This allows drawing conclusions about the acoustic behaviour of the plate, the influence of the complexity and detailing of the model, the influence of the position of the excitation on the structure-borne sound, etc. It is also shown that the considered uncertainties are well captured by the presented method.