Nonlinear Dynamic Analysis of High Speed Unbalanced Rotor Supported on Deep Groove Ball Bearings Considering the Preload Effect

Abstract

The presented paper deals with the study of dynamic behavior of unbalanced rotor along with internal radial clearance (IRC-C3) as non-linearity. Even though the perfect alignment and precision manufacturing has been done, unbalance force cannot be eliminated completely. The dynamic behavior of a high speed unbalanced rotor supported on deep groove ball bearings (SKF-6205) has been studied along with internal radial clearance (IRC-C3) of 14 μm. Nonlinear dynamic response observed by keeping rotor speed constant and the preload as control parameter. The mathematical model has been developed considering both nonlinear contact stiffness and damping at the contact between rollers and races. The contact of rollers with races are treated as nonlinear springs with contact damping whose deformations are obtained by using Hertzian elastic contact deformation theory. The numerical integration technique Runge-Kutta-Fourth-Order method is used to solve the coupled nonlinear differential equations iteratively. Various techniques like Orbits plots, Poincare map and power spectra are used to study the nature of response. It has been concluded that even though the IRC of bearing cannot be change, once the bearing is installed, the system can be made stable by giving optimized preload to the bearing.