Internal damping in rotating shafts

This paper analyses the influence of internal damping on the dynamic behaviour of rotating shafts. The problem is faced considering the presence of nonlinearities introduced in the restoring elastic forces by the alternate compression and extension of the shaft fibres; these forces show a component that can oppose or drive the shaft whirl motion. The analytical solutions obtained allow to describe the transient motion of the shaft and to evaluate the stability limit, whose value slightly differs from the classical one determined with linear approaches.