INFLUENCE OF SHAFT MATERIAL DAMPING ON THE STRESS FLUCTUATIONS IN A ROTOR SUPPORTED ON FLUID FILM BEARINGS

The unbalance whirling motion of a rotor supported on fluid film beari ngs, under certain circumstances, can induce severe stress fluctuation s in the rotor shaft. This stress fluctuation can be attributed to the backward component of the elliptic whirling motion of the rotor. The present investigation studies the influence of shaft material damping on the stress fluctuations and explores the possibility of attenuating this stress fluctuation through control of shaft material damping. Th e result indicates that an optimum amount of material damping in the r otor shaft can improve the performance of flexible rotors supported on fluid film bearings.