Hybrid Finite Element-Transfer Matrix method for vibroacoustic applications

This paper is concerned with the development of a hybrid methodology to speed up finite element analysis in vibroacoustic applications. The approach aims at avoiding the finite element modeling of the noise control treatment, which is cumbersome from both computational (i.e. model size) and virtual prototyping (i.e. meshing) standpoints. A transfer matrix model is instead employed, allowing for a reduction of the computational burden and a substantial simplification of the multilayer modeling. The methodology relies on the assumption that the noise control treatment is flat, homogeneous and of infinite lateral extent (i.e. finite size effects are neglected). The latter hypothesis implicitly assumes that the response of the treatment is controlled by the direct field contribution. However, although such assumption seems to be justified by short wavelength and large dissipation, it is shown that finite size effects within the noise control treatment may be important if a finite element comparable accuracy is required. Hence, a simple correction based on the image source method is proposed to retrieve the missing reflected field contribution.