Sound transmission of structures. A finite element approach with simplified room description

A theoretical prediction model for the sound insulation of a wall is an important tool when developing new wall structures. A full description of the entire room-wall-room system in a theoretical model for sound insulation is still today too computation-intensive, implying that the sound insulation at higher frequencies cannot be studied. Some simplifications must thus be introduced. The simplification proposed in this present paper is to describe the rooms with waveguides, i.e., infinity-long rooms. The model then reduces to the (more or less) two-dimensional wall. The question of how to apply the excitation then arises. The choice proposed here is to use a combination of diffuse field and Monte Carlo simulations. The incident and radiated power, expressed in waveguide modes, are used to calculate the transmission loss. A minor literature survey is also included, as well as numerical results and comparison with experimental results. The method presented is developed to study the sound insulation of lightweight double-leaf walls, and the numerical results of such walls are presented