The Research On Modeling And Dynamic Behavior Of Air Spring System Of High Speed EMU

The continuous improvement of the operating speed of China’s high-speed railways and the vigorous development of dense high-speed railway networks have put forward higher requirements for the driving safety and stability of high-speed EMUs.Air spring suspension systems have been It is one of the core technologies of high-speed EMU bogies,which directly affects the smoothness and safety of the vehicle.Therefore,the research and development of high-speed EMU air spring characteristic modeling is of great significance to the study of vehicle dynamic characteristics,and can better meet the requirements of passengers’ riding comfort under high-speed EMU driving at high speed.In view of the influencing factors of the rubber airbag material that cannot be ignored in the current air spring dynamic model,and the vertical and lateral coupling characteristics under the joint simulation of the air spring and high-speed EMU,the constitutive relationship of the air spring rubber material should be further studied,Commended the non-linear characteristic factors such as the viscoelastic force,friction force and linear elastic force of the rubber material,combined with the aerodynamic characteristics of the air spring,and finally established the vertical-transverse coupling dynamic model of the air spring,based on the model The influence of air spring characteristics on vehicle running stability,driving stability and safety is discussed.In order to calculate the aerodynamic parameters of the air spring and apply it to the construction of the dynamic model of the air spring,this paper analyzes the non-linear factors such as contact,fluid-solid coupling and rubber superelastic material of the air spring under deformation,respectively A finite element model was established for the rubber bladder,orifice,and additional air chamber of the air spring.The accuracy of the model was verified based on the measured data.The functional relationship between the aerodynamic parameters and the loading displacement was summarized.Torsional stiffness characteristics in the state.The results show that the static torsional stiffness decreases greatly with the increase of the torsional arc,and the torsional stiffness value increases with the increase of pressure;the dynamic torsional stiffness is related to the internal pressure and frequency of the air spring,the greater the internal pressure,the stiffness The greater the frequency,the greater the frequency and the greater the stiffness.The establishment of the dynamic model of the vertical characteristics of the air spring can be better applied to the dynamic calculation of the vehicle.Considering that the vertical nonlinear characteristics of the air spring are more obvious,the main air chamber,the additional air chamber and the air spring of the air spring are based on the aerodynamic theory.The characteristics of the orifice are described separately,and the parameters used in the numerical calculation are identified by the finite element method,and the vertical aerodynamic model of the air spring is established.The rubber airbag is modeled using the fractional order theory.The Oustaloup transfer function describes the viscoelastic damping characteristics of the rubber airbag.A fractional order correction model is established to achieve the correction of the aerodynamic model.The air spring test verified the revised model,and summarized the air spring stiffness and damping characteristics under different excitation amplitudes,loads and frequencies.The vertical stability characteristics calculated by joint simulation show that the revised model has a vertical stability index lower than the aerodynamic model by about 6%.In order to optimize the lateral dynamic characteristics of the air spring of the high-speed EMU and make it meet the joint simulation calculation with the whole vehicle,the deformation equation of the rubber airbag is derived by analyzing the stress state of the rubber airbag under lateral deformation.The structural relationship characterizes the friction force and linear elastic force of the rubber airbag,and the transverse nonlinear model of the air spring is established.Based on the measured data and the finite element method,the friction,linear elasticity and dynamic parameters were identified.The experiment verified the accuracy of the model and explored the influencing factors of the lateral stiffness characteristics of the air spring.The results show that the air spring model considering the characteristics of the rubber airbag can describe the sharp corner effect at both ends of the stiffness hysteresis curve,and is closer to the test curve;the air spring lateral model calculated by the joint simulation can improve the calculation accuracy of the train passing curve.The vertical-transverse coupled dynamic model of the air spring is improved by optimizing the vertical and lateral dynamic models,which can improve the dynamic performance of the high-speed EMU.The joint simulation of the coupled model shows that the straightness can reduce the vertical of the car body Directional and lateral stability indicators and maximum acceleration values;the lateral characteristics of the coupled model under the curve state cannot be ignored.Although the curves of the lateral model and the vertical model meet the limits of various aspects through the safety indicators,but under high-speed driving and The coupling model still presents different degrees of difference;the safety indicators of different curve radii vary significantly with vehicle speed.To ensure passenger comfort experience,high-speed EMUs are suitable for curve radii greater than 7000 meters.