Numerical Investigation of AMB Supported Rotor Interaction with Auxiliary Bearing

This paper describes numerical analysis of interaction between rotor and auxiliary bearing due to high transient overloads. When the fast spinning rotor interacts with the auxiliary bearing that does not move, some critical states of motion are possible. One of these motions, backward whirl, reaches very high frequencies and thus can produce very high loads on rotor and bearings, which can lead to the destruction of the machine. The detailed model of the AMB supported rotor auxiliary bearing system considers discontinuous stiffness caused by bearing clearance effects, auxiliary bearing fixed or flexible mount types, nonlinear Hertzian contact stiffness and Coulomb friction forces. Numerical investigations as time history, orbit diagram, bifurcation diagram, Poincaré section diagram are proposed to study the system parameters which extremely influence the whole dynamic response. One of the important parameters, rotor driving frequency, can be modelled as time variable parameter in the detailed system model. Moreover, parameters used in the detailed model discussed in this paper obtained from experimental test rig.