Quasi-periodic response and stability analysis for a non-linear Jeffcott rotor

A modified HEM (Harmonic Balance Method)-AFT (Alternating Frequency Time) method is developed to obtain quasi-periodic responses of a horizontal Jeffcott rotor with a bearing clearance. Two truncated double harmonic expansions are used for calculating accurate quasi-periodic responses. The winding number, which is created as an unknown period occurring due to cross-coupling force terms in the non-linear rotor system, is obtained by applying the FFT algorithm. The stability analysis is performed with only input frequency (rotational speed), which reveals rich dynamical characteristics in a non-linear Jeffcott rotor for quasi-periodic motion. (C) 1996 Academic Press Limited