Final Thesis

Sound source localization on a car body based on beamforming using transfer functions

Master Thesis of Havolli, Albulena

The acoustic and vibro-acoustic-technical comfort of vehicles (NVH) raises in importance, especially in the premium segment. In order to fully exploit its own development potential and continue to make progress towards its competitors, the advancement of acoustic de-velopment tools is of central importance for OEM (Original Equipment Manufacturer). As a successful development tool for the localization and characterization of noise outside and inside the vehicle, the beamforming has proven to be the method. The localization of a sound source which inducts structure-borne sound into the car body, which is emitted as an air sound into the vehicle cabin by the interior boundary, is currently not possible. Thus, with the existing conventional beamforming algorithms (CBF), only a locating of the air-borne radiation, but not of the structure-borne sound generation, is possible. This master thesis is intended to contribute to the improvement of beamforming for sound source detection in the vehicle interior by using transfer functions. For this purpose, in the first step, the transfer functions of defined structural points of the car body are determined experimentally (by striking with the impact hammer). In the next step, these transfer func-tions are implemented in an existing beamforming environment. To validate the beamforming approach using transfer functions, the car body is excited with a shaker at the defined positions. The localization results of this approach and the corres-ponding method without the inclusion of transfer functions are recorded, compared and qualitatively evaluated.