Dynamic characteristic analysis of lubricated bearing in flexible rotor system using real-time coupled finite element model

The flexible characteristics of the rotor shows a significant influence on the dynamic characteristics of the lubricated bearing. This study presents a real-time coupled finite element model (FEM) that combines the flexible rotor, interfacial lubrication and ball kinematics for the mechanism investigation. The ball-raceway lubrication is analyzed by comprehensively considering the ball spin speed, preload, contact angle, surface roughness to obtain the dynamic stiffness of the ball-raceway interfaces. This stiffness is incorporated in FEM to analyze the dynamic response of the rotor-bearing system, which will affect the lubrication and kinematic behavior of the bearing in turn. The accuracy of the model is experimentally verified. The results show that influenced by the dynamic behavior of the flexible system, the contact pressure, spin speed, rotation speed and spin-roll ratio of the ball increase rapidly when the system undergoes extreme vibration. Furthermore, lubrication will reduce contact stiffness, exacerbate the impact of flexibility, so the contact angle and rotation velocity distribution of the balls will be more uneven, especially in areas of low pressure.