DYNAMIC ANALYSIS OF UNSYMMETRICAL FLEXIBLE ROTOR-BEARING FOUNDATION SYSTEM UNDER AN UNSTEADY OIL-FILM FORCE

摘要

Based on an unsymmetrical rotor model, the dynamic analysis of an unsymmetrical flexible rotor-bearing-foundation system supported by short journal bearing is presented, considering anisotropy of foundation stiffness and asymmetry of rotor stiffness. A more reasonable nonlinear unsteady oil-film force model, which is determined only by three functions, is adopted in the paper and the explicit analytical formula of oil-film force for short journal bearing is used. Using the Runge-Kutta method, the influence of parameters on the unsymmetrical flexible rotor-bearing-foundation system is investigated. Numerical results show that instability of system may be improved by decreasing the asymmetry of rotor stiffness and increasing the stiffness of foundation.