Description and Calibration of the ISO Tapping Machine in Numerical Impact Sound Predictive Tools

One of the main challenges in wooden constructions is to be able to achieve good acoustic insulation, especially in the low-frequency range. The prediction of acoustic performance of wooden buildings before erection becomes important and reliable predictive tools are in great need so that accurate predictions are done in a time- and cost-efficient manner. To end that, the first question that arises is how to accurately model the excitation source generating the structure-borne sound. Regarding impact sound insulation performance of floors, the procedures presented in the ISO 10140-3 employ the tapping machine as standardized source. Although some investigations have been carried out in recent years aiming at analytically describing the tapping machine as well as modelling it, no satisfactory agreements between modeled and simulated results were achieved. In the investigations reported here, the extension of an existing frequency-domain method to include the tapping machine into finite element predictive tools is presented. Different parametric studies were carried out to investigate how different uncertainties influence the accuracy of the results. Finally, experimental tests were performed to further calibrate the numerical model.