Study On Applicability Of Secondary Vertical Multi-Functional Damper For Railway Vehicle

With the continuous increasing of the running speed of high-speed railway vehicles,the vehicles are required to have good running stability and suitable anti-roll stiffness,so as to ensure the safety of rolling motion caused by factors such as vehicle passing through curve,crosswind and track irregularity.A secondary vertical multi-functional damper(hereinafter referred to as multifunctional damper)is proposed,which has the function of restraining vehicle vertical vibration and rolling motion at the same time,which not only reduces the amount of suspension elements,but also has safer compared with the anti-roll torsion bar.The research on its applicability in railway vehicles in this thesis has important theoretical and engineering application value.Firstly,the structure and operating principle of the multi-functional damper are explained.The secondary vertical damper on both sides of the vehicle body are cross connected through pipelines.Damping elements are installed at the connection between the damper and the pipeline,and an energy accumulator is connected to each pipeline.Through the different flow modes of oil and the mutual cooperation of various components,the multi-functional damper occupied the function of restraining vertical vibration and rolling motion,and realizes the decoupling of rolling motion and vertical motion of vehicle body.Secondly,according to the structural characteristics of multi-functional damper and based on the flow characteristics of fluid,the mechanical models of key components such as damping element,accumulator,pipeline and joint are established,which lay a theoretical foundation for the study of the mechanical characteristics of multi-functional damper.The physical model of multi-functional damper is established based on the software AMESim,which provides research basis for the study of dynamic performance of multi-functional damper.Then,compared with the bench test of secondary vertical damper,the characteristics of multi-functional damper are studied,and the multi-functional damper model is verified to have good performance and better accuracy.The principle of nonlinear anti-roll stiffness of multifunctional damper is analyzed.At the same time,the influence of the structural parameters of the key components on the performance of multi-functional damper is analyzed.The results show that the diameter of the normal through hole and the diameter of the pipeline are negatively correlated with the damping force of the damper;the pre tightening force of the damping valve,the pre charging gas pressure of the accumulator and the working chamber diameter of the damper are positively correlated with the damping force of the damper;and the precharge gas pressure of the accumulator and the working cavity diameter of the damper are positively correlated with the anti-roll stiffness;The nominal volume of the accumulator is negatively correlated with the anti-roll stiffness.According to the influence law of structural parameters on the performance of damper and the feedback information of vehicle dynamics,the structural parameters of multi-functional damper are optimized,and the structural parameters of the multi-functional damper adapted to the target vehicle are obtained.Finally,the real-time interactive joint simulation model of the railway vehicle with multifunctional damper is established on AMESim/Simulink/SIMPACK software.The vehicle dynamics performances are compared with or without secondary vertical damper,the results show that the multi-functional damper can improve the vehicle riding stability before and after unloading,which is basically consistent with the performance of secondary vertical damper;The vehicle dynamics performances equipped with or without anti-roll torsion bar are compared,the multi-functional damper can greatly improve the vehicle operation safety when the vehicle passing through curve or crosswind condition,and has more secure than the vehicle equipped anti-roll torsion bar.Therefore,the secondary vertical multi-functional damper can be better suitable for railway vehicles.