Vehicle Acoustic Sensitivity Performance Using Virtual Engineering 2011-01-1072
In order to assess the possible ways of energy transfer from the various sources of excitation in a vehicle assembly to a given target location, frequency based substructuring technique and transfer path analysis are used. These methods help to locate the most important energy transfer paths for a specific problem, and to evaluate their individual effects on the target, thus providing valuable insight into the mechanisms responsible for the problem. The Source-Path-Receiver concept is used. The sources can be from the road surface, engine, transmission, transfer case, prop-shaft, differential, rotating components, chain drives, pumps, etc., and the receiver can be driver/passenger ears, steering column, seats, etc. This paper is devoted to identify the noise transfer paths and the force transmissibility among the interfaces of different components in the vehicle for the low to mid frequency range. The dynamic stiffness matrix, obtained by inverting the dynamic compliance, is being used as a superelement database of the main structure and is connected to the substructures by isolators or rigid bolts, depending on the attachments. The acoustic response at the driver's and passenger's ears is computed for the excitation at spindles. Robust optimization technique is adopted to optimize the various mounts/bushings, and vehicle performance is demonstrated by identifying and diagnosing the issues related to noise and vibration. The virtual techniques employed in this project are very efficient, economical and versatile for the automotive and aerospace applications.