Building Acoustics 01: Finite Element Model of a Building Acoustics Test Facility to Predict the Sound Transmission Loss Based on DIN EN ISO 10140

In the context of building acoustics, sound transmission loss estimations are crucial to quantify the noise pollution in buildings. When developing building prototypes in the sense of an acoustics-oriented design process, it is desirable to have a wave-resolving virtual prototype, especially in early development stages, to estimate, for instance, the influence of different material or geometry configurations on the sound transmission loss. Such a virtual prototype can be derived by applying the finite element method. Hence, this contribution aims to present a simple finite element model of a building acoustics test facility in accordance with DIN EN ISO 10140 for the measurement of the sound transmission loss of single- and double-leaf walls with and without insulation. The model serves as a benchmark for testing and developing direct solver strategies with a decent computational effort. In doing so, geometry and mesh creation was realised in SALOME 9.15 whereas the institute's in-house research code elPaSo was utilised for the matrix assembly and solving procedure. First, elPaSo was numerically verified by means of a code-to-code comparison with the commercial software COMSOL 6.3 using a small-scale test facility. Afterwards, the large-scale test facility finite element model was created using a frequency- and domain-specific discretisation approach. Finally, sound transmission loss profiles of three different test specimens were estimated in one-third-octave bands from 8Hz to 630Hz and compared to ideal profiles reported in the literature that are based on simplifying assumptions. Only partial agreement was observed; possible reasons for these discrepancies are discussed throughout the contribution.