Vibration based operational modal analysis of rotor systems

A novel method is proposed for operational modal analysis OMA of linear rotor systems, combined with correction technique of spectrum analysis (CTSA), harmonic wavelet filtering (HWF), random decrement technique (RDT) and Hilbert transform (HT) method. With CTSA method, operational frequency component is reconstructed and subtracted from rotor vibration signal. The residual signal is composed by harmonics of operational frequency and several model responses. The single mode responses can be obtained by HWF and then RDT method is employed to process these responses, respectively, to extract single mode free responses of the rotor systems. Finally, HT method is applied to obtain modal parameters of the rotor systems from these single mode free responses. The experimental results of the proposed method are close to those of the finite element method which indicates that the proposed method is effective in practical applications.