Study On The Influence Of Characteristic Parameters Of Hydraulic Shock Absorber On The Dynamic Performance Of High Speed Electric Multiple Units

Today,with the rapid development of the high speed trains,people have the higher requirements on riding quality,stability and safety of the train.As the key component on train dynamics performance,the hydraulic shock absorber has a good deal influence on critical velocity,wheel/rail wear,riding quality,derailment coefficient and so on.Though the hydraulic shock absorber of high speed train in China at present is relay on imports,imports market share mainly by the German and the Japan,and the imports add up to hundreds millions CNY.In recent years,the country’s investment in railway record highs.By the end of 2016,the national’s railway add up to 124 thousands kilometers,of which 22 thousands kilometers high speed railway,ranking the first in the world.So,we urgently need to realize the localization of hydraulic shock absorber in high speed train to solve the shortage.At present,the hydraulic shock absorber is the main damper of high speed train in China,and its major performance depend on the rubber joint stiffness and damping characteristics.In order to learn the influence of rubber joint stiffness and damping characteristics of hydraulic shock absorber on high speed train dynamics performance,the CRH380 B EMU is taken as basic model,based on the vehicle dynamics theory,and according to actual train parameters to build the vehicle dynamics model using the SIMPACK which is multi-body dynamics software.There is no inter-vehicle longitude damper on CRH380 B EMU.The vehicle model is extended to eight vehicles model with four motors and four trailers which is added the coupler and inter-vehicle longitude damper.The motor and the trailer are distinguished by the torque on wheelsets.Finally,the accuracy of train model is verified by the comparison of changing velocity and actual experiments.Take the yaw shock absorber,secondary lateral shock absorber,primary vertical shock absorber and secondary vertical shock absorber original value of rubber joint stiffness and damping characteristic as basis to increase or decrease.Research the influence of rubber joint stiffness and damping characteristic on vehicle dynamics performance through the change of parameters in a certain range.In the start,brake,straight line,curve line and other conditions,through install the inter-vehicle damper or not to research the effect on the train dynamics performance.It’s not convincing to research the influence of independent shock absorber parameters on dynamics performance,a good combination of parameters for the other indicators may be bad,and there may be a contradiction between the indicators.In order to get the best matching relation of the damper parameters,using the Box-behnken experiments and quadratic polynomial fitting to find a response surface about damping of yaw damper,damping of secondary lateral damper,rubber joint stiffness of yaw damper,rubber joint stiffness of secondary lateral damper with critical velocity,wear number and riding quality.At the same time,the minimum of critical velocity,derailment coefficient,and wheel load reduction rate are selected as the constraint and test for the analysis result.The optimal parameters are obtained finally.The research results shows that rubber joint stiffness and damping of yaw damper have a great effect on dynamics parameters.When rubber joint stiffness reduce to 2MN/m,and the damping reduce to 40% original damping value,the dynamics performance has a sharp deterioration,the critical velocity reduce to287km/h and 248km/h which can’t reach the requirement of safe operation.The characteristic parameters of secondary lateral damper have some influence on the vertical and lateral dynamic performance.The characteristic parameters of primary vertical shock absorber and secondary vertical damper have a great influence on the vertical dynamic performance.Installing the inter-vehicle longitudinal damper has a great improvement on the lateral and longitudinal dynamics performance of the train,and it can restrain the yaw angle of the car body.After the multi-objective optimization,the optimization result is reduced by 1.49%-3.52% compared with the original value in the lateral riding quality,wear index,derailment coefficient and wheel load reduction rate,and the RMS value of frame lateral accelerate reduce 40.5%.Finally,the causes and precautions of the optimization results are analyzed.The study contents can further accelerate the nationalization process of the high speed train hydraulic shock absorber,and provide theory reference and basis for the actual production and application of the hydraulic shock absorber.