Dynamics Study On The Vibration System With Clearance In Railway Vehicle

The train will inevitably be affected by the gap,dry friction and other factors,in the high-speed operation process,so that the vehicle system tends to show a complex vibration phenomenon.This behavior not only reduces the comfort of the passengers,but also the stability and safety of the vehicle system,the fatigue life of its parts and components caused serious impact.This article is for consideration of this issue,from the longitudinal and vertical direction angle of the train,Three types of collision-bearing vibration systems in common rail vehicles are used as engineering background,and the corresponding models are abstracted for dynamic analysis.So as to study the movement of the system under different parameters.In this paper,three kinetic models are analyzed as follows:Firstly,a dynamic model of two-degree-of-freedom bilateral vibro-impact system is established,which is based on t the case of shock and vibration of the coupler.The conditions of analytic solution and periodic motion of the system are deduced by mathematical analytic method,and the Poincaré mapping and Jacobi matrix of the system are obtained based on disturbed motion.The influence of the change of the gap value on the dynamic behavior of the system is analyzed by numerical simulation.It is found that under the appropriate parameters,the change of system gap affects its bifurcation behavior,When the gap value d is large,the system will exhibit stable periodic motion in the larger excitation frequency range.However,with the increase of the gap value d,the dynamic behavior of the system tends to be complicated in a certain parameter range.It is also proved that there are complicated dynamic behaviors such as Hopf bifurcation and torus doubling bifurcation even in simple car hook system.Secondly,on the basis of the study of the coupler system,a dynamical model of four degrees of freedom with clearance is abstracted from the longitudinal angle of the train.In the same way,it is found that the dynamical behavior of the high-dimensional system is more complicated,not only Hopf bifurcation,torus doubling bifurcation,but also under certain parameters conditions will occur Hopf-Hopf codimension two bifurcation.And their evolution to the chaos is also complex and diverse,such as the formation of T2 ring,singular "tire-like" quasi-periodic attractors and so on.At the same time,it is concluded that the bifurcation value becomes smaller and the bifurcation behavior of the system is advanced with the increase of the gap value d under certain parameters.However,With the dimensionless quality ratio um4 decreases,the bifurcation value becomes smaller,bifurcation occurs hysteresis behavior of the system,the bifurcation behavior of the system is delayed and the bifurcation behavior of the system is changed.When the um4 is large,the Hopf bifurcation is not only the existence of the Filp bifurcation.Finally,from the vertical angle of the train,a kind of three-degree-of-freedom simple wheel-rail lumped parameter vibration model is established.It is found that although the system has Hopf bifurcation and torus doubling bifurcation in different parameters,the path of their evolution to chaos is not the same.By analyzing the process of the system to the chaos evolution,the evolution of the system periodic motion instability to the chaotic motion is obtained.The range of parameters of periodic motion and chaotic motion of the system is obtained,which also lay the foundation for the study of the occurrence of chaotic motion in the later suppression system.