Author(s): Schoenwald Stefan, Tröbs Hans-Martin
The assessment of structure-borne sound intensity is a very useful tool to visualize the power flow due to flexural waves in plates, beams and shells. In this research the structure-borne sound intensity is determined from the surface velocity distribution of a vibrating structure using a well-established finite differences approach. Velocity data measured in a dense grid on the surface of an orthotropic solid wood wall with a scanning laser Doppler vibrometer was used to calculate the structural power flow. As further input data the flexural wavenumbers along the different principal directions of an orthotropic solid wood wall were required and thus were measured as well. The wall was part of a building junction that supported a segmented prefabricated concrete-wood composite floor, so that it was possible to excite the wall directly or indirectly across the building junction. The power flow in the wall was visualized for different excitation cases, for example by a single point force on the wall or on one floor segment, as well as by a distributed excitation of the complete floor with airborne sound. Besides qualitative also energetic considerations on the power flow are made for the validation of the applied methods.
Name: Dr Stefan Schoenwald