Independent characterization of structure-borne sound sources using the in-situ blocked force method

The vibro-acoustic behavior of systems and components in modern vehicles play an increasingly important role in the development process of high quality products in automotive industry. In order to characterize the numerous mechanical, electrical and mechatronic systems, many of which embody significant sources of structure-borne sound and vibration, advanced measurement techniques are required. Ideally, such characterization techniques should allow specifying supplier components on a test rig without the necessity of conducting vehicle measurements to allow a better understanding of the NVH behavior at an early stage in the development process. This paper investigates the applicability of the in-situ blocked force method as a receiver-independent approach for the characterization of an electrical steering system. First, blocked forces are obtained from test bench measurements to characterize the system at its multiple connection points. In a second step, the blocked forces are transferred to a second structure to predict the receiver response in a different installation. The accuracy of the in-situ blocked force approach is investigated by comparing the predicted response with actual measurements. Finally, the usability of the obtained data for a virtual prediction of the interior sound pressure is discussed.