A wave based model to predict the sound transmission through multilayered structures between two rooms

In building acoustics, reliable prediction methods for sound transmission loss and sound radiation are required for parameter studies, material selection and optimization studies. Today there is a lack of calculation techniques which can be use in the entire frequency range of interest (50-5000 Hz). At high frequencies, prediction methods based on statistical energy analysis or analytical approaches can be used. However, low frequency sound insulation has become more important recently due to the increasing presence of noise sources at low frequencies and the use of lightweight constructions in buildings. In this paper, a numerical prediction tool for building acoustical purposes is presented. It can be used in a broad frequency range to simulate the direct sound transmission through finite-sized, multilayered structures between two rooms. The wave based methodology is used to solve the acoustic part of the problem. A modal approach, based on the Rayleigh-Ritz method, is adopted to describe the structural responses. A numerical validation with the finite element method is shown. Furthermore, the model is validated with sound insulation measurements of single and double panels performed in the transmission chambers of the KU Leuven. The model is afterwards used to discuss the influence of plate boundary conditions and plate dimensions on the sound insulation. Keywords— building acoustics, sound transmission loss, multilayered structures, wave based model