Prediction of the sound transmission loss of two-dimensional periodic structures with a hybrid framework
* Presenting author
When considering a room-wall-room system to simulate a transmission suite in an acoustic laboratory, the direct sound transmission in the mid-frequency range can be obtained using a hybrid framework. The wall is then modelled deterministically as finite size effects and modal behaviour are still important, while the rooms carry a diffuse field and are modelled as stochastic subsystems. The finite element method is usually employed to compute the modal behaviour of the wall. At higher frequencies the computational cost then increases significantly as a finer mesh is required. For this reason, an alternative approach was recently developed, which allows to replace the finite element model by an analytical model for finite-sized thick and layered walls. However, the application of this approach is limited to layered structures such as sandwich panels or double glazing. In the present work, the efficient modelling of more complicated building elements which exhibit spatial periodicity, will be considered by invoking periodic structure theory. As a first application, the sound transmission loss of a brick wall is examined and compared to the predictions of a thick wall model with equivalent material properties and to experimental data.