| Along with the rapid development of railway modernization construction,more and more high-speed railway has been put into operation,which has also made a great progress about railway transport industry.The issues of high-speed train system dynamic performance are taken seriously increasingly because of the rapid development.In particular,Air spring as a key component of the vehicle system,the dynamic problems of the air spring suspension system has become the focus of research in recent years.The accuracy of its model directly affects the analysis of vehicle system dynamics.The main purpose of this thesis is to study the nonlinear dynamic characteristics of the air spring suspension system,in the meantime,which also is to discuss the impact about the stability,comfort and safety of the vehicle system.Based on the theory of fluid mechanics,aerodynamics and the thermodynamics,the formula expressions about stiffness and damping of the air spring suspension system are derived,and the influence of parameters on the characteristics of air spring suspension system also is analyzed.Which showed that the air spring is affected by many factors,including the volume of the additional chamber,the diameter of the orifice,the effective area of the air spring,the amplitude and the vibration frequency all have a obviously effect to its nonlinear and linear vibration situation,which can provide the basic theory for the dynamic analysis of air spring suspension system.Considering about the different situation of the orifice,the single degree of freedom nonlinear dynamic model and two degrees of freedom nonlinear dynamic model about air spring suspension system are established.The approximate analytic solution of the nonlinear vibration equation which is obtained by using the harmonic balance method and the averaging method.The influence on the key parameters of the air spring system which is analyzed to the amplitude frequency curve.The main resonance state and the stability of the air spring suspension system are analyzed and studied further in this thesis.Simultaneously,the theoretical calculation results of linear and nonlinear air spring suspension characteristics are compared with the experimental data,which shows that the nonlinear air spring model is closer to the actual situation and has better damping characteristics.Referring to the calculate empirical formula of lateral stiffness of air spring system,the formula expressions about lateral stiffness for the air spring suspension system model is derived.based on this,a nine degree of freedom lateral half vehicle model is established,the vibration stability of the vehicle is analyzed by changing its parameters.On the basis of the nonlinear dynamic model of air suspension system,the seventeen degrees of freedom whole vehicle model about high-speed train is established,the vibrationmovement states of the nodding,the bouncing,the rolling vibration about vehicle which are analyzed according to different speed,the results showed that the nonlinear dynamic model of air spring can meet the damping requirements of vehicle system,and also can ensure the stability and comfort of vehicle system dynamic. |
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