Nonliner Dynamic Analysis Of Rotor System For Locomototive Traction Motor

In recent years,with the rapid developent of science and technology,China's high-speed trains,city rail transit has developed rapidly and continuously toward high speed and heavy load in the direction of development.So the locomotive traction motor rotor system stability and reliability are faced with more severe challenge.Because traction motors are directly installed on wheelsets and bogies,improving the stability of traction motor rotor system has an important influence on improving locomotive operation quality,ensuring operation safety and reducing wheel rail force.Firstly,the thesis bases on the theory of nonlinear dynamics and rotor dynamics and aimed at the specific characteristics of traction motor rotor system,By the law of friction and Newton's second law are used to establish the nonlinear dynamic model of the system under different working conditions and dimensionless.The four order variable Step Runge-Kutta method is used to solve the system numerically.The nonlinear vibration of the system is analyzed through Poincare map,bifurcation diagram,axis orbit map,phase diagram and time history diagram.Secondly,a model of traction motor rotor system is simplified to a single disc rotor system in the thesis.The dynamic response characteristics of a single disc rotor system are analyzed based on the variation of main parameters such as eccentricity and speed ratio.The calculation results shows that the system may have double period bifurcation,quasi periodic and chaos in the range of a certain value.By means of numerical integration,the bifurcation diagram,Poincare map and orbit map of the system in a parameter domain are obtained.The motion characteristics of the system are obtained through comparative analysis of the graphs.Finally,when considering the nonlinear contact force and nonlinear rub impact force Hertz system is caused by the Hertz contact force and radial clearance of bearings.The results show that when the rotational speed of the traction motor rotor system changes,the dynamic response of the system appears periodic motion,quasi periodic motion and chaos,and there is a phenomenon of jumping directly from one cycle to chaos.The increase of the speed leads to the increase of the system instability interval.At lower rotating speeds,the system is mainly based on periodic motion.With the increase of the rotating speed,the unstable interval of the system response will increase;The clearance of the bearing and the emergence of chaos is largely dependent on the radial clearance of the bearing.With the increase of the clearance,the unstable region and the chaotic response area will be increased.