Influence of lateral vibrations on the whirling characteristics of gear-pinion rotor system

Abstract

The proposed work presents a methodology to analyze the influence of lateral vibrations on the whirling characteristics of a rotor-bearing system. A complex variable approach, which is proposed for the analysis of a single rotor system, is very powerful for this purpose. The approach is expanded to the analysis of a combined rotor system to apply it to the gear system analysis. The bearing stiffness and shaft flexibility of the geared rotor system are taken into account in two ways. With regard to the rotor effect, the frequency response functions are obtained for both torsional motions and coupled lateral-torsional motions. By obtaining the differences in the frequency responses of both the models, the effect of neglecting rotor effects in gear dynamics simulation is studied. The lateral stiffness of the system, which reflects the shaft and bearing stiffness, is considered to make a strong lateral and torsional motion coupling. It is shown that the lateral vibrations have considerable effect when the natural frequencies of the lateral vibration and torsional vibration are close to each other, which is expected. The effect of lateral-torsional coupling on gear dynamics is discussed based on the response of the system.