Nonlinear vibrations of the rotor with variable mass settled in journal bearings

In this paper the nonlinear vibrations of the rotor-bearing system are analyzed. The rotor is a shaft disc system supported in journal bearings. Mass of the rotor is variable. One the rotor the fluid force and the impact force due to mass variation act. The mathematical model of the system is the nonlinear second order differential equation. An aapproximate analytic method is developed for solving of the equation. The so obtained solutions are compared with numerical ones. The results are in good agreement.