Applicability of the structure-borne sound source characterisation Two-Stage method as well as the parameters derived in sound pressure level predictions in lightweight constructions

Abstract

When predicting structure-borne sound-induced sound pressure levels, in addition to describing the sound propagation path through the building structure as exactly as possible, it is necessary to characterise the vibration behaviour of the structure-borne sound sources. The investigations described here were carried out to extend the applicability of the structure-borne sound source characterisation two-stage method described in EN 15657 and to describe its uncertainties. Furthermore, the suitability of the structure-borne sound parameters determined with TSM in the sound pressure level prediction according to EN 12354–5 was tested and statements on the achievable accuracy were derived. For both methods - characterisation of structure-borne noise sources and prediction of structure-borne noise-induced sound pressure levels - data on prediction accuracy are only available to a very limited extent but are essential for a reliable prediction model.Firstly, different sources of structure-borne sound were characterised using the two-stage method on different reception plates. In the process, structure-borne sound sources with defined acting moments were also investigated to analyse their influence on characterisability. Using the characterised vibration parameters of the structure-borne sound sources, the power introduced into different reception plates was then calculated and compared with measurements to establish the achievable accuracy of the characterisation method.Subsequently, the investigated structure-borne sound sources were installed in a lightweight test stand and the resulting sound pressure levels were measured in an adjacent receiving room. These were compared with the sound pressure levels predicted according to EN 12354–5 to obtain reliable statements on the achievable accuracy when using source quantities determined using TSM in the normatively described prediction procedure for structure-borne sound-induced sound pressure levels. A mean deviation between predicted and measured sound pressure levels of approx. 7 dB could be determined across all investigated sources.