An approach using active structural acoustic control: for the reduction of structure-borne road noise

A complete analysis of the structure-borne noise transmission paths of an automotive suspension assembly is presented. First, a fully-instrumented test bench consisting of a wheel/suspension/lower suspension A-arm assembly was de- signed in order to identify the vibro-acoustic transmission paths (up to 250 Hz) for white noise excitation of the wheel. Second, an analysis of the vibro-acoustics of the suspension is presented; an overview of the Frequency Response Functions (FRF) is introduced and their respective modal behaviors are described. Frequency response function measurements between the excitation signal and each suspen- sion/chassis linkages are used to characterize the di®erent transmission paths that transmit energy through the chassis of the car. Finally, a synthesis of the major modal contributions of the suspension is drawn, with the objective of indicating which suspension transfer paths contribute the most to the structural forces trans- mitted to the chassis. Modal transmissibility factors (MTF) were calculated to pro- vide an overall classi¯cation of the modes to the vibration transmission through the individual suspension linkages and the orthogonal directions.