Structure-borne Sound Power Characterisation from Single and Multiple Contact Sources at Low Frequencies using Heavyweight Reception Plates
* Presenting author
In heavyweight buildings, structure-borne sound from machinery is often problematic at low- and mid- frequencies. A prediction model to predict the sound transmission from machinery to nearby rooms is described in EN 12354-5. As input to this model, the characteristic structure-borne power can be determined using the reception plate method described in EN 15657-1. This paper investigates the influence of single and multiple contact sources using a validated finite element model of a heavyweight reception plate. Comparison of the direct injected power and the reception plate power leads to the lowest differences when the reception plate power is obtained from a regular grid of sampling positions over the whole reception plate using harmonic point forces of randomly distributed single contact sources. A numerical approach is used to assess different sampling strategies in order to minimise the number of measurement positions. The predicted vibrational behaviour of different harmonic point force excitation on the reception plate is compared with measurements on a laboratory reception plate. In practice, building machinery usually consists of more than one contact point. Hence, multiple contact sources such as white goods are taken into account by using different excitation positions on the validated reception plate model.