Stiffness and damping coefficients for rubber mounted hybrid bearing

A non-contact passive magnetic bearing has a low friction compared with other passive (journal or ball) bearings. But these bearings have negligible damping due to which even small rotor vibration impacts the bearing magnet. It results in breakage of brittle magnetic materials. To overcome this problem, a hybrid bearing (passive magnet+elastomer) has been proposed in the present manuscript. To select an appropriate rubber, a step-by-step approach, using pendulum and hysteresis tests, has been followed. A parametric study on thickness of selected rubber was carried out. Experiments were conducted on three configurations: (i) a stand-alone magnetic bearing, (ii) magnetic bearing with a butyl rubber having a thickness of 1mm, and (iii) magnetic bearing with a butyl rubber having a thickness of 1.5mm. To investigate the effect of rubber Young’s modulus on the damping, rubber was made softer by immersing in aromatic liquid, and the experiments were repeated using softer rubber. Copyright © 2014 John Wiley & Sons, Ltd.

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