Design of a Passively Magnetically Stabilized System with Viscoelastic Damping Support and Flexible Elements
Sprache des Titels:
ISMB16, the 16th International Symposium on Magnetic Bearings
Using passively magnetically stabilized degrees of freedom in magnetic levitated reduces the complexity and therefore costs. In the investigated system only two degrees of freedom remain to be controlled actively. One is the rotation and the other is the axial position of the rotor, which is stabilized by an axial active magnetic bearing (AMB). However, the application of passive magnetic bearings (PMBs) features some drawbacks. One of the main problems is caused by the poor damping in PMBs, which leads to exaggerated deflection amplitudes in the resonance frequencies. This results in the necessity of external damping. One possibility is given by utilizing viscoelastic materials. But these materials show highly frequency and temperature dependent properties. Thus, only a proper model of the rotor dynamics including the nonlinear characteristics of the damping material allows for calculating the displacements of the system parts. Furthermore, also flexible parts have to be considered, if their bending modes fall within the range of operation. This article describes the rotor dynamic modeling of a passively magnetically stabilized system including the nonlinear behavior of a viscoelastic damping support as well as the consideration of the relevant flexible body modes. With this model an optimization can be performed to guarantee contact-free operation. Finally, the analytical model is verified by measurement.