Multiphysics Modelling and Experimental Verification of Active and Passive Reduction of Structural Noise

A fully-coupled multiphysics modelling is applied for the problem of simultaneous active and passive reduction of noise generated by a thin panel under forced vibration providing many relevant results of various type (noise and vibration levels, necessary voltage for control signals, efficiency of the approach). The active approach is validated experimentally. To this end, the plate of panel is excited in order to generate a noise consisting of significant lower and higher frequency contributions. Then, the low-frequency noisy modes are reduced by actuators in the form of piezoelectric patches glued with epoxy resin in locations chosen optimally thanks to the multiphysics analysis. The emission of higher frequency noise should be attenuated by well-chosen thin layers of porous materials. A fully-coupled finite element system relevant for the problem is derived; such multiphysics approach is accurate: advanced modelling of porous media can be used for porous layers, the piezoelectric patches are modelled according to the fully-coupled electro-mechanical theory of piezoelectricity, the layers of epoxy resin are considered, finally, the acoustic-structure interaction involves modelling of a surrounding sphere of air with the non-reflective boundary conditions applied in order to simulate the conditions found in anechoic chambers. The FE simulation is compared with some experimental results. The sound pressure levels computed in points at different distances from the panel agree excellently with the noise measured in these points. Similarly, the computed voltage amplitudes of controlling signal turn out to be good estimations.