Uncertainties of Transfer Path Analysis and Sound Design for Electrical Drives

The objective of this dissertation is to examine the influence of possible uncertainties during the measurement of transfer paths in systems with vibro-acoustic properties such as machines or vehicles. The transfer path could be an acoustic, structural or complex vibro-acoustic system. Uncertainties can occur due to internal and external factors during the measurement process. The trend of uncertainty propagation in sampled acoustic and structural transfer paths is studied both analytically and experimentally. The relative standard deviation of the transfer paths, in comparison with the reference sample, is calculated to assess the uncertainty propagations. A statistical approach is applied to the system in the higher frequencies to evaluate the error propagation. In particular, the influence of tonal input excitation on the propagation of uncertainties is modeled to determine the behavior of the system. The dissertation also investigates the contribution of uncertainties to sound design parameters with four sources of input excitations. The objective assessment involves the calculation of the psychoacoustic parameters, and subjective evaluation is performed with a listening test. As a final investigation, the uncertainty analysis is applied to the measurement of the transfer path in an electric vehicle.