Influence of Unequal Pedestal Stiffness on the Instability Regions of a Rotating Asymmetric Shaft : 3rd Report, Mechanism for Occurrence of Two Types of Unstable Vibrations

抄録

Two types of unstable vibrations occur because of the asymmetry in the shaft stiffness. To understand the mechanism for the occurrence of these unstable vibrations, the authors clarify the conditions necessary for their occurrence. A torque applied to a shaft end tends to increase the whirling amplitudes of the shaft. The conditions for instability of free vibration thus obtained are ascertained by an analog computer. If the higher order of small quantities, that is, the rotating asymmetry of shaft stiffness and inequality of pedestal stiffness, is taken into consideration, a number of very narrow instability regions can be made to occur.