Damage diagnosis of rotors: Application of Hilbert transform and multihypothesis testing

In this paper, a combined approach to damage diagnosis of rotors is propose d. The intention is to employ signal-based as well as model-based procedure s for an improved detection of size and location of the damage. In the firs t step, Hilbert transform signal-processing techniques allow for a computat ion of the signal envelope and the instantaneous frequency, so that various types of nonlinearities due to damage may be identified and classified bas ed on measured response data. In the second step, a multihypothesis bank of Kalman filters is employed for the detection of the size and location of t he damage based on the information of the type of damage provided by the re sults of the Hilbert transform.