Abstract
Operational Modal Analysis also known as Output Only Modal Analysis has in the recent years been used for extracting modal parameters of civil engineering structures and is now becoming popular for mechanical structures. The advantage of the method is that no artificial excitation needs to be applied to the structure or force signals to be measured. In this paper the non-parametric technique based Frequency Domain Decomposition (FDD), as well as the more elaborate Enhanced Frequency Domain Decomposition (EFDD) identification technique are discussed. The methods are illustrated by measurements on a Volvo S60 passenger car in operating conditions on a dynamometer.