Study On Nonlinear Dynamics Of A Comlex Rotor System With GAS Bearing Support

Rotating machinery is one of the most important equipment in national foundation establishment and industry.Rotor-bearing system is the key part of the rotating machinery,and plays an irreplaceable role in many fields of industry.With the development of modern industry, rotating machinery is becoming more complicated and requires working at high speed.In this case,the traditionnal method in which rotor-bearing system was simplified to collective quality is not applicable to this rotating machinery.In this paper,a practical beating-rotor system is discussed.First,the model of the rigid foundation bearing-rotor system and the elastic foudation bearing-rotor system were performed by FEM.Then a reduction calculation method based on fixed interface component mode synthesis was applied to dramatically reduce the dimension of the original system.The number of degrees of freedom of rigid foundation bearing-rotor system is reduced sharply from 60 to 12,and the elastic,from 64 to 16.After reduction,the newmark method is applied to solve the equation of motion.By the numerical calculation,the results showed that there are abundant complex nonlinear dynamic behaviors in the dynamic system.Through comparison of the results between the rigid foundation bearing-rotor system and the eslastic,it is found that the stability of the rotor system is improved obviously when the mass,coefficients of damper and stiffness match with each other reasonably.