Using enhanced frequency domain decomposition as a robust technique to harmonic excitation in operational modal analysis

The presence of harmonic components in the measured responses is unavoidable in many applications of Operational Modal Analysis. This is especially true when measuring on mechanical structures containing rotating or reciprocating parts. This paper describes a new method based on the popular Enhanced Frequency Domain Decomposition technique for eliminating the influence of these harmonic components in the modal parameter extraction process. For various experiments, the quality of the method is assessed and compared to the results obtained using broadband stochastic excitation forces. Good agreement is found and the method is proven to be an easy-to-use and robust tool for handling responses with deterministic and stochastic content.