Gyroscopic Whirling of a Simple Rotor

Abstract

In chapter 1, the whirling of the Jeffcott rotor has been treated, where the gyroscopic and rotary inertia effects were not included in the model. The equations of motion for such a rotor therefore failed in reflecting the phenomena due to rotation, not different from ordinary non-rotating structures. The only difference between the analyses of the Jeffcott rotor and non-rotating structures is the nature of the excitations exerting on the rotor. The rotation-related terms in the system equations seem to appear in some occasions; however, they are the results of coordinate transformation from one coordinate system(normally the stationary coordinates) to another(normally the rotating coordinates), which are the pure mathematical consequences. In this sense, it can be stated that the Jeffcott rotor is not truly a rotor model but a model of a non-rotating simple structure subject to rotating excitations. The very nature which enables the rotor model rotation comes from the neglected gyroscopic and rotary inertia effects. In this chapter, the classical Jeffcott model is extended to include the gyroscopic and rotary inertia effects, and its stability and whirling characteristics are investigated.