Research On The Influence Of Lateral Stop On Vehicle Dynamic Behavior

In recent years,the rapid development of high-speed EMUs has made the research and development of bogies more and more important.The lateral stop is one of the important structures to alleviate the impact of the bolster and the frame in the bogie.In order to avoid excessive deviation between the bogie of the EMU and the car body,a lateral stop is usually provided when designing the bogie,so that a certain gap is left between the lateral stop and the car body.The gap is a strong nonlinear factor that will have an important impact on the lateral dynamics of the vehicle,and indirectly affect the running quality of the vehicle.Therefore,it is necessary to conduct a deeper and more detailed exploratory research on the nonlinear dynamic characteristics of the vehicle lateral stop elastic collision suspension system.Secondly,a comprehensive analysis of the nonlinear dynamic behavior of the lateral stop suspension system of high-speed EMU vehicles can provide a certain theoretical basis for the design of the lateral stop suspension system.First of all,considering that the high-speed running of the vehicle is laterally excited by track irregularities,a mechanical model of a single-degree-of-freedom EMU vehicle with a lateral stop suspension system is established.According to Newton’s second law,the system’s differential equation of motion is established,its piecewise analytical solution is obtained,the Poincaré map of the system is established,and the stability of the system is explored with Floquet’s theory.Then,the fourth-order Runge-Kutta numerical integration method is used for numerical simulation experiment.The time course diagram,Poincaré cross-section diagram and bifurcation diagram were studied,and it was found that the evolution path of inverse doubling bifurcation appeared on the road to chaos of the system and jumped out of chaos.Finally,the influence of frequency parameters on the vehicle system is discussed,which provides a theoretical basis for the design of the lateral stop suspension system of a single-degree-of-freedom vehicle.Secondly,considering the influence of the wheelset on the system,a two-degree-of-freedom vehicle with lateral stop suspension system was established.According to the state space method,the differential equation of motion of the system is established,and the piecewise analytical solution is obtained.By analyzing the influence of the displacement excitation of the wheelset on the lateral stop system of the vehicle,changing the excitation frequency of the bifurcation parameters obtains: increasing the damping coefficient of the lateral stop,the stability of the system will be more stable.Then the classic bifurcation behaviors such as Hopf bifurcation.Neimark-Sacker bifurcation,and period-doubling bifurcation appear on the system’s road to chaos.Finally,by analyzing the influence of parameter changes on the vehicle lateral stop system,it provides a theoretical basis for the design of the two-degree-of-freedom lateral stop.Finally,on the basis of the two-degree-of-freedom vehicle lateral stop suspension system,considering the influence of the car body on the vehicle suspension system,a three-degree-of-freedom vehicle including a lateral stop suspension system is established.List the system’s differential equations of motion,find the piecewise analytical solution,and use the semi-analytical method to analyze the system’s response.It was found that the three-degree-of-freedom vehicle stop system has more than one road leading to chaos.Finally,the influence of wheelset displacement excitation frequency on EMU vehicle system is discussed,which provides a certain theoretical data reference for the design of three-free vehicle with lateral stop suspension system.