Stability analysis and dynamic behaviour of a flexible asymmetric rotor supported by active magnetic bearings

Abstract

The objective of this work is to show the influence of dynamic characteristics of Active Magnetic Bearings (AMBs) on the stability and dynamic response of an asymmetric and unbalanced rotor. Indeed, AMBs have been successfully applied in several industrial machinery facilities. Their main advantages are the contactless working principle, frictionless suspension and operation in very high speeds. Firstly, the AMBs dynamic support parameters have been obtained through electromagnetic theory. Then, a generalized system equations of motion have been derived using the finite element method. The motion of a rotor the shaft cross-section of which is asymmetric is generally governed by ordinary differential equations with periodic coefficients. Floquet's theory is used to investigate the stability of this system of equations. Finally, numerical simulation results are presented and discussed.

Vibration Behavior of Misaligned Rotor with the Asymmetric Shaft Using Theory of Timoshenko Beam

“…He utilized complex model that consist of higher degrees of freedom. Hili et al [21] analyzed the stability and dynamic behavior of an unbalanced and asymmetric rotor to indicate the effect of dynamic features of Active Magnetic Bearings (AMBs). Raffa and Vatta [22] derived the differential equations of motion for an asymmetric shaft using Timoshenko beam theory.…”

Optimization of Design Parameters for Manufacturing a Radial Active Magnetic Bearing with 12-Poles

“…Modal analysis was then performed for the free-free boundary conditions for the rotor system with bearing conditions when the rotor speed was equal to 20000rpm. Attica Hila et al [5] showed the influence of dynamic characteristics of an AMB on the dynamic response and stability of an unbalanced and asymmetric rotor. Indeed, the AMBs have been successfully employed in many industrial machinery facilities.…”

Using Floquet Theory in the Procedure for Investigation of the Motion Stability of a Rotor System Exhibiting Parametric and Self-Excited Vibration

“…Srinath, et al [14] presented an approach to derive generalized criteria for determining the stability/instability regions of any asymmetric rotating shaft system and showed its applicability for comparison with experimental results and other practical applications. In [15], the stability analysis of an asymmetric shaft discretized by finite elements is evaluated using Floquet theory. The stability of the rotor system is improved here by tuning of radial active magnetic bearing parameters.…”