Predicting the dynamic behavior of rotor systems on ball bearings

Abstract

Analysis tools for predicting the dynamic behavior of a rotor system supported by ball bearings are presented. Two computer programs were developed. The first uses a transfer matrix technique to compute rotor natural frequencies as a function of bearing stiffness. The second is a bearing analysis program which is used to determine ball bearing stiffness as a function of load and speed. High-speed effects as well as combined axial and radial loading are considered. Together, these programs provide the necessary information for constructing the critical speed map of a rotor system. Analysis of an actual rotor system was performed and the results discussed. The importance of the compliance of the bearing housing with respect to the bearing itself is emphasized.