Nonlinear dynamic behaviors of a bolted joint rotor system supported by ball bearings

Abstract

A dynamic model of the rotor-bearing system with bolted joint structure is set up based on the Lagrange’s equations, which considers the bearing clearance, the gyroscopic effect and the initial deformation due to the non-uniform preload. The nonlinear dynamic responses of the system were obtained by using the Runge–Kutta–Fehlberg method, and then the influence of the radial bearing clearance on the nonlinear dynamic behaviors of the rotor system is studied by means of bifurcation diagram, frequency spectrum, shaft orbits and Poincare maps. The results indicate that the larger bearing clearance will make the system enter into chaotic motion at a lower rotating speed. In addition, with the increase in bearing clearance, the duration of the chaotic motion becomes longer. Furthermore, the influence of initial deformation on the stability of the bolted joint rotor system with bearing clearance is studied. The results show that when the bearing clearance is present, the instability speed of the rotor system will gradually rise with the increase in initial deformation. Meanwhile, as the bearing clearance continuously increases, the regions of the chaotic motion become less and smaller, and the motion state should be completely changed under certain initial deformation. The related results can provide guidance for the optimization and design of the bolted joint rotor-bearing system.