Identification and diagnosis of rotating flexible bent shafts

The responses of shaft bow and their relationships with unbalance responses and mechanical or electronic run out are analyzed based on the theory of rotor dynamics. The responses of shaft bow are separated from the unbalance responses successfully by making use of vibration information under different rotor runs. An identification method of thermal bend is presented based on the 2D-holospectrum technique. Experimental results show that when bow phase is steady and amplitude is variable, the tangent of initial phase point on the 2D-holospectrum is parallel, which can be effectively used for diagnosis of bent shaft.