The Effect of Damping and Stiffness of Bearing on the Natural Frequencies of Rotor-bearing System

In this paper, the effectiveness of stiffness and damping of bearing is investigated on the natural frequencies of the rotor-bearing system. The rotor-bearing system consists of a shaft, two bearings and a disk between two bearings. Parallel spring-damper in horizental and vertical directions is considered for modeling the stiffness and damping of bearings. The gyroscopic effect is also considered in derivation of equations, together with its dependence on speed. Numerical results contain the critical speed of shaft for various values of bearing stiffness and damping. Moreover, the first six natural frequencies of rotor are presented in Campbell diagrams.