Design and modeling of semi-active squeeze film dampers using magneto-rheologicalfluids

Abstract

Conventional squeeze film dampers (SFDs) have shown their effectiveness in suppressingunbalanced vibrations in rotor systems, particularly supported by rolling element bearings.Recently, there is an increasing demand for ‘controllable’ SFDs to meet the needof modern rotating machinery, characterized by high operating speed and highload capacity. Thus, this paper presents a controllable semi-active SFD usingmagneto-rheological (MR) fluids, focusing on its design and modeling. It offers acomprehensive design method and an innovative experimental identification and modelingtechnique for MR-SFDs. The primary goal of the MR-SFD design is set to maximizeits dynamic control bandwidth, and the design method includes the materialselection, magnetic circuit analysis and sealing element design. After constructing aprototype MR-SFD based on the final design, this work investigated how someof the critical design parameters affect the performance of the MR-SFD (i.e. itsdynamic control bandwidth change). Furthermore, it characterized the damper’sdynamic behavior experimentally using a novel excitation method that adopts activemagnetic bearing (AMB) units. Unlike conventional methods, the AMB system wasable to precisely control the amplitude and frequency of the input excitation,enabling us to obtain the nonlinear dynamic stiffness properties of the MR-SFDwith varying input current. In modeling the dynamic behavior of the MR-SFD,this study employed the describing function method. The describing functionanalysis effectively captured the nonlinear dynamic behavior of the MR-SFD.