Vibration attenuation of a rotor supported by journal bearings with nonlinear suspensions under mass eccentricity force using nonlinear energy sink

This paper studies the effect of a number of smooth nonlinear energy sinks (NESs) on the vibration mitigation of a rotor supported by journal bearings with nonlinear suspensions under mass eccentricity force. The NESs have a linear damping and an essentially nonlinear stiffness. Two NESs in the perpendicular directions are located on the bearing body. The equations of motion are derived and numerically solved. In order to optimize the parameters of the NESs, a genetic algorithm is utilized. For different values of the system parameters, periodic, two-periodic (2T) and qusai-periodic motions, occur in the system. It is shown that the NESs reduce effectively vibration of the rotor-bearing system in an operating speed range. However, the type of motion does not change in the most rotational speeds of rotor. Furthermore, for lower values of damping, the NESs demonstrate a high performance.