Whirling of Shafts with Asymmetric Stiffness

Abstract

The whirling of a shaft with asymmetric stiffness and viscous external damping and with its mass concentrated at a point has been investigated. General solutions for the transient and forced whirls are given and are illustrated by records obtained from an analogue computer simulation of the shaft. Also experiments have been carried out on a test shaft with special arrangements for the control of damping and for the excitation of forced whirls. The region of instability, the forms of the transient whirls, and the forced whirls produced by out-of-balance force have all been examined in detail. In addition, it is shown that as the rotational frequency of an asymmetrically stiff shaft increases above the upper limit of instability its whirl behaviour tends towards that of a symmetrically stiff shaft.