Two magnetorheological elastomer devices for the control of aerostatic thrust bearing: Thru regulating air flow or surface curvature

摘要

In this paper two novel controlling elements made of magnetorheological elastomer (MRE) for aerostatic thrust bearing have been developed. An electromagnet was integrated in the bearing to trigger the contraction of the elastomer In the mode of 'flux control', the performance of the bearing depends on the air flux flowing through the gap between a MRE ring and the central mandrel. While in the mode called 'curvature control,'' changing the magnetic field can bend the MRE orifice shape and deepen the recess of the bearing. The air pressure distribution and the load capacity of the bearing are altered accordingly. The load-elevation relationships can be manipulated In spite that the flux-control design yields a more monotonic relation between control voltage and load capacity, the performance is very sensitive to the accuracy of assembly and dimension of the MRE part. On the other hand, the curvature-control one shows a more complex performance while keeps the better repeatability of experimental results. A simple dynamic test showed that the MRE bearings have both the acceleration and frequency of resonance less than that of the typical design However, the first two resonance frequencies of the curvature-control bearing are higher than that of the flux-control one Another interesting finding is that when the MRE is charged, the acceleration of the flux-control bearing upsurges, but it plunges for the curvature-control one.