RESEARCH ON NONLINEAR DYNAMICS OF MARINE ROTOR-BEARING SYSTEM UNDER COMPLEX TRANSPORT MOTIONS

In order to reveal the nonlinear dynamics behavior of the marine rotor-bearing system under complex transport motions (heaving, swaying, yawing and pitching), the dynamical model of the rotor-bearing system with the nonlinear oil film force and transport inertial forces was built based on, Lagrange’s equation.The effects of the rotating speed and transport motion parameters on the nonlinear dynamics behaviors of the system were mainly analyzed. The results show that the amplitude and oil film whirl interval of the system are larger when considering the coupling motion of heaving, swaying, yawing and pitching than those when not considering this motion. Affected by the coupled transport motion, the rotor will deflect obviously at a lower speed. At a certain rotational speed, with the increase of heaving amplitude, swaying frequency or swaying amplitude, the amplitude jump phenomenon caused by the oil whirl appears in the vibration response of the system， and the motion state of the system undergoes quasi-periodic and chaos. With the increase of swaying frequency, yawing amplitude, yawing frequency, pitching amplitude or pitching frequency, the system is always in a quasi-periodic vibration state, but the vibration amplitude of the rotor increases in varying degrees.