On the hysteresis phenomenon associated with instability of rotor-bearing systems

A method is presented for predicting the occurrence of a hysteresis phenomenon, which is observed in experimental results dealing with the instability, of rotor-bearing systems. The method is based on the Hopf bifurcation theory. It is shown that the existence of a hysteresis phenomenon is dependent upon the systems operating parameters. To this end, the effect of oil viscosity on the hysteresis phenomenon and its implications oil the rotorbearing instability are investigated. The results of a series of experiments illustrating the effectiveness of the prediction of the hysteresis phenomenon using the Hopf bifurcation theory are also presented.