Modelling and vibration analysis of misaligned rotor-ball bearing systems

Abstract

A dynamic model is derived for misaligned rotor-ball bearing systems driven through a flexible coupling by treating the reaction loads and deformations at the bearing and coupling elements as the misalignment effect. In order to verify the validity of the misaligned rotor system model, experiments are extensively carried out with a laboratory test rig. Both the experimental and simulation results agree well in that, as the angular misalignment increases, the whirling orbits tend to collapse toward a straight line and the natural frequency of the misaligned rotor system associated with the misalignment direction increases largely. It is found that the increase in natural frequency is mostly due to the increase in effective bearing moment stiffness associated with the misalignment direction. (C) 1999 Academic Press.