QUASI-PERIODIC RESPONSE AND STABILITY ANALYSIS FOR A NONLINEAR JEFFCOTT ROTOR

A modified HEM (Harmonic Balance Method)-AFT (Alternating Frequency Ti me) method is developed to obtain quasi-periodic responses of a horizo ntal Jeffcott rotor with a bearing clearance. Two truncated double har monic expansions are used for calculating accurate quasi-periodic resp onses. The winding number, which is created as an unknown period occur ring 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 quas i-periodic motion. (C) 1996 Academic Press Limited