THE BEHAVIOUR OF THE JEFFCOTT ROTOR UNDER A VIBRATING BASE OF FLUID FILM BEARING
Keywords:
Jeffcott rotor, Lagrangian, fluid film bearings, whirl orbitsAbstract
The whirl motion of the Jeffcott rotor was investigated. The system was analyzed by setting up thekinetic, potential, and dissipation energy equations, and the excitation was assumed as a randomvibration on the base of the fluid film bearing of the rotor. Lagrangian was used to derive theequations of motion in the Y and Z directions and the Simulink under Matlab software was used tosimulate the current system. The simulation was carried out under a constant rotational speed anddifferent masses for the shaft and the disk. In addition, the effect of changing the stiffness and thedamping coefficients is also investigated. The responses of the two coordinates (Z and Y) were alsoobserved as well as the whirl orbits of the shaft for different mass ratios. Furthermore, the stability of thesystem was investigated mathematically. The results show that the whirl motion is stable when therotor speed is 8,000 rpm, while the mass ratio of the disk and the shaft is 0.4.
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