Influence of Unequal Pedestal Stiffness on the Instability Regions of an Asymmetrical Rotor

抄録

A shaft carrying an asymmetrical rotor is supported by upper and lower flexible bearing pedestals each of which has a directional inequality of stiffness ε=0∼1 and a concentrated mass. The analysis of this problem is carried out on the assumption that ε is either negligibly small or not so. The positions, width and number of unstable regions are analytically determined. The analytical results show a good coincidence with results obtained by an analog computer. Two sorts of unstable vibrations result due to the inertia asymmetry of the rotor. The mechanism of the unstable vibrations can be explained. The conditions for the occurrence of the unstable vibrations can be obtained, and all vibratory solutions obtained by an analog computer satisfy these occurrence conditions.