| With the rapid development of heavy-haul railway,the longitudinal impulse performance will be aggravated with the expansion of train axle load and formation plans.Train accidents such as coupler broken,separation and derailment occur frequently,which bring threatens to the running safety and efficiency of the heavy-haul trains.These were common serious engineering problems faced by the world's heavy-haul railway countries.Many factors that affect the longitudinal impulse of heavy haul-train,and large number of theoretical and experimental researches have been carried out at home and abroad.The longitudinal dynamic performance of the train was affected by various factors,such as coupler slack and braking operation mode.However,there were not many studies on this.Based on the theory of train longitudinal dynamics,taking HXD2 new eight-axis electric locomotive traction 10,000 t heavy-haul train as an example,the influence of coupler slack and braking operation mode on the longitudinal impulse of heavy-haul train was investigated.Then explored the critical release speed of train speed adjustment brake on long down slope.Related research results enable supplying theoretical reference for the operation of 10,000 t heavy-haul train.Based on the theory of train longitudinal dynamics,a longitudinal dynamics model of HXD2 new eight-axis electric locomotive traction 10,000 t heavy-haul train was established.The traction force characteristics,brake force characteristics,coupler-bumper characteristics,and various running resistance characteristics were carefully considered in the model.The longitudinal dynamics simulation and analysis platform for heavy-haul train was introduced.This platform has a visual input interface,and it has ability to analyze the longitudinal dynamic performance of various marshalling.The longitudinal performance of heavy haul train is verified by the measured data obtained by the research team.Results indicate that,as to train speed,train displacement and train maximum coupler force,the simulation results agree well with the experimental results,which indicates that the model has high reliability.Because of the discrepancies in braking operation mode and railway condition,there are some differences between simulation results and experimental results.The influence of coupler slack on the longitudinal impulse of heavy-haul train was investigated,which includes the size of coupler slack,the number of large slack coupler as well as the distribution pattern of coupler slack.The longitudinal dynamic performance of train equipped with drawing-bar is also calculated.Analysis shows that,the coupler slack has little impact on train maximum coupler force when start process and resistance braking process.During service braking,train maximum coupler force and train maximum acceleration would be increased with the size of coupler slack and the number of large slack coupler.Train coupler force is the maximum when the distribution pattern of coupler slack is convex,and the minimum is concave distribution.By assembling the drawing-bar,the maximum coupler force of the train can be greatly reduced.For the phenomenon of the oversized coupler transverse angle in resistance brake,the influence of braking operation mode on longitudinal impulse was explored.Results indicate that,increasing the brake handle lifting time,that is to say,slowly increasing the brake handle can reduce the longitudinal coupler force of train to a certain extent.Under the premise of controllable speed of train and no risk of overspeed,the use of lower handle level can effectively reduce the longitudinal coupler force of train.According to the relationship between release time and train pipe refillable time,the train critical release speed of speed adjustment brake on long down slope was defined.After this,a calculation method of critical release speed was proposed.Combining with a cases,research on the calculation method was applied,and then the calculation method was verified.Results showed that it has higher accuracy. |
PDF Full Text Request