Design And Simulation Test Of Nonlinear Suspension System Of High Speed And Super Stable Freight Train On Existing Lines

Since the British railway was built in the 19th century,high-speed,heavy load and super stable transportation have been the goal of the railway i ndustry.Due to the limitations of linear vibration isolation theory,it is difficult for the linear secondary suspension system of freight car bogie to have the ability of heavy load and high speed operation at the same time.In order to solve the problem,this paper proposed,designed and verified a nonlinear secondary suspension system with high static and low dynamic characteristics based on nonlinear vibration isolation theory.First of all,a spring-rod-mass system(SRMS)with high static and low dynamic characteristics is proposed,on the basis of which a two-bar-spring-mass system(simplified SRMS)is evolved.The harmonic balance method is used to obtain the steady-state response of the two-bar-spring-mass system under the simple excitation.The amplitude frequency characteristic of the system is analyzed,and the condition of infinite resonance of the system is obtained.The effects of system parameters and external excitation parameters on the transmission rate and initial isolation frequency are analyzed in detail.Secondly,the simulation model of the freight train with nonlinear secondary suspension is established using multi-body dynamics simulation software SIMPACK.Under the actual excitation spectrum of Zheng-Wu railway track,the straight-line running stability and curve trafficability of the improved vehicle and the original vehicle are compared and analyzed,and the influence of the connecting rod length of the nonlinear secondary suspension system on the straight-line and curve trafficability of the freight train is discussed.Finally,according to the theoretical analysis and simulation results of improved freight train,a physical prototype model of nonlinear secondary suspension with high static and dynamic characteristics is designed.The multi-rigid body model and rigid flexible hybrid model of nonlinear secondary suspension are established using multi-body dynamics software ADAMS.The static and dynamic simulation tests are carried out under light load and heavy load conditionsr,respectively,the simulation results shown that the physical prototype system of the nonlinear secondary suspension system has good vibration isolation performance under the condition of light and heavy load.Under the condition of ensuring the structural strength of the connecting rod,the flexibility of the connecting rod has little effect on the vibration isolation performance of the secondary suspension prototype model.