Research On Braking Characteristics Of Heavy Haul Train

With the rapid development of the world economy,railway transportation is gradually becoming main current in transportation industry.In order to satisfy the increasing demand for railway transportation,it is imperative to train the heavy haul trains.However,the stress situation of heavy haul train is more complex than that of common trains,especially in braking process.Due to the delay of the transmission of the brake wave,the vehicle braking can only follow the direction of the length of the train,which causes the difference between the two adjacent compartments.If the longitudinal impulsion is oversized,the problems such as couplers rupture even train derailment will be caused.Therefore,the study of braking characteristic becomes one of the major research works of train longitudinal dynamics.In addition,the braking process in heavy haul trains is a very uncertain process.In the past,many studies have considered the braking process as a deterministic problem,which often leads to large error analysis.At present,interval analysis method is one of the effective solutions to the uncertain problem.This paper focuses on longitudinal dynamics problem of the heavy haul trains and makes research about braking characteristic.The main contents are as follows:1.The model of heavy haul trains was built by introducing multi-parameters mathematics simplified method,and using Fortran language.A series of researches were carried out on brake cylinder air inflation pressure by changing more than one parameter,including the brake control valve characteristic,brake cylinder inflation characteristic and brake wave propagation characteristic parameters.Then the fitting curves were made to summarize the first train,middle train and tail train's changing trend.The influence of the parameters on the pressure in the process of charging the brake cylinder was calculated and compared,and the uncertainty interval of the braking system parameters was analyzed.2.The heavy haul trains longitudinal dynamics uncertain interval model was presented by the interval analysis method theory and based on the used model of coupler force.A series of researches were carried out on maximum coupler force of all trains by changing parameters.Through the analysis of the data about changes to the maximum compression coupler force and maximum hook load,the effects on the parameters were compared and analyzed.Then the trend was summarized.The conclusion will provide a theoretical reference for the related design and optimization.3.In view of time-consuming computation in the building model for heavy haul trains longitudinal dynamics,considering the longitudinal dynamics model to get maximum coupler force as samples,using polynomial response surface method,the surrogate model was established.Through the modeling for heavy haul trains and interval analysis witih uncertain parameters,the influences of braking parameters on the filling pressure of brake cylinder and the maximum coupler force were obtained.All these provide a valuable reference for the further study of heavy haul trains longitudinal dynamics.