Effect of unbalanced rotor on the dynamics of cylindrical roller bearings

Abstract

In present study, the non-linear dynamic behavior of a rigid-unbalanced rotor supported on cylindrical roller bearing is analyzed. An analytical model of the rotor-bearing system is developed for the investigation. The Hertzian contact between the bearing components and the clearance are considered as source of nonlinearities in the study. The contact between the rolling elements and races is model using nonlinear spring-mass system. Stiffness of nonlinear spring is calculated by Hertzian elastic contact deformation theory. Responses show system behavior as periodic, sub-harmonic and chaotic at different rotor speed. All the results are presented in form of fast Fourier transforms and Poincarè maps. Presence of instability and chaos in the dynamic response has been observed as the speed of the rotor-bearing system is changed. The study shows that the interaction of varying compliance (VC) frequency due to parametric excitation and rotational frequency (X) due to the unbalanced rotor force.