FE-based approach to compute the sound transmission loss of building partitions

This paper investigates a numerical approach to compute sound transmission loss of building partitions and other structures. This method requires that, a unit cell, a small portion of the considered partition, is modelled by using the Finite Element Method (FEM), and coupled with semi-infinite fluid domains on both sides. On the sending side, the structure is excited by an acoustic plane wave. Bloch-Floquet periodic boundary conditions are applied in order to consider the structure of infinite extent. The infinite sound transmission coefficient of the considered partition is computed from the sound field variables obtained from the FE simulation. To increase the accuracy of the results below the critical frequency, the finite-size radiation impedance can be considered. The transmission loss computed with this approach is comparable with the results obtained by means of the transfer matrix method (TMM). In this study the validation of the results, obtained with the FE approach, and an assement of their accuracy were achieved by comparing them with the sound transmission loss computed using the TMM. Moreover, the influence on the results of practical aspects of the implementation of the model, such as dimension of the unit cell, the number of elements in the perfectly matched layer domains, the extension of the fluid domains and the size of the mesh were investigated by means of a parametric analysis.