Nonlinear dynamic behavior of a water-lubricated hybrid bearing-rotor system
In this study, the stability analysis is carried out on a water-lubricated hybrid bearings used as the support of a high-speed motorized spindle. A two-dimension finite element method considering turbulence effect has been developed to solve the nonlinear oil film force. This paper mainly studies the influence of the water supply pressure, rotating speed, and unbalance mass on the axis orbit of the rotor-bearing system. The results of the axis orbit indicate that the effect of nonlinear for the hybrid bearing studied in this paper is not obvious, and the bearing-rotor system can run safely and stably at the rotating speed not more than 30000 rpm.
A study of steady state and transient performance characteristics of a flexible shell journal bearing
Abstract A computer-aided study of static and dynamic performance characteristics and linear and nonlinear transient motion analysis of a flexible shell journal bearing system is presented. Trajectories of the journal-centre motion have been drawn to predict the transient response of the system. It is concluded on the basis of results presented in this paper that the motion trajectories obtained using nonlinear equations of motion give a much higher stability margin in terms of critical mass than those obtained through linearized analysis.
The performance characteristics of thin compliant shell journal bearings
The static and dynamic characteristics of a thin compliant shell journal bearing are determined. The film profile modified by deformation is established by obtaining with an iterative procedure a matched steady state solution for the pressure field in the fluid film and the deformation in the bearing shell. Dynamic characteristics are determined in terms of the bearing stiffness and damping coefficients, the critical mass of the journal and the whirl frequency for a journal bearing having an aspect ratio of 1.0 and eccentricity ratios up to 0.8 and are compared for various values of the deformation coefficient. The study shows appreciable changes in performance characteristics due to bearing deformation. The stability margin of the journal bearing system changes significantly with the deformation coefficient.