On The Modelling Of Flexible Rotor/Magnetic Bearing Systems When In Contact With Retainer Bearings

Magnetic bearings offer many advantages over conventional bearings, but they have to incorporate retainer or backup bearings due to their limited force capacity. Understanding the contact dynamics and controlling the rotor when it is in contact with the retainer bearings are important issues for the successful use of magnetic bearings in safety critical and wider applications. The contact dynamics are complicated and various analysis techniques have been suggested in the literature. These include modelling contact forces as non-linear functions of penetration depth. In this paper, an alternative method based on the constrained Lagrange equations of motion is introduced. Simulation results show its ability to predict a rotor contact orbit with competitive computational efficiency.