The Longitudinal Dynamics Simulation Of 20,000-ton Heavy Haul Train

With the rapid development of railway transportation,high speed and heavy load have become the main direction of railway development.However,along with the running of heavy haul train,the longitudinal dynamics problems are exposed particularly prominent.With the increase of vehicle weight and configuration length,the longitudinal impulse of the train becomes more intense during the braking transmition.And during the actual running of the train,the brake-failed vehicle also causes great impact on the longitudinal impulse.Therefore,it is of great practical significance to apply the simulation system to analyze the longitudinal dynamics of 20,000-ton heavy haul train.In this paper,by analyzing the braking transmition characteristics of the 20,000-ton heavy haul train and using the TABLDSS simulation system to solve the problem of the longitudinal impulse of the train after releasing,and then analyzing the effect on longitudinal impulse of brake-failed vehicles' position.The experiment results are verified by the simulation system.On the basis of the simulation system accuracy,the influences of the changes of electric braking force,initial releasing speed,initial braking speed and the different brake pipe pressure reduction on the longitudinal impulse of the train are calculated by the simulation system.And then using the simulation system analyzes the longitudinal dynamic performance of different brake-failed vehicle position under three conditions of common brake pipe pressure reduction of 50kPa,full brake application and emergency application.The results of simulation show that the form of the coupler force is mainly squeezing force in the brake processing of 20,000-ton heavy haul train.And due to the releasing inconsistent of the train,the longitudinal impulse occurs in the process of the release.The impacting force increases obviously,and the coupler force of the train is first impacted and then squeezed.The maximum coupler force can be effectively reduced by adjusting the electric braking force of locomotive.The maximum impacting force can be reduced by increasing the electric braking force and the maximum squeezing force can be reduced by decreasing it.With the increasing of initial releasing speed,the coupler force is more and more small.The maximum impacting force of initial releasing speed 60km/h is reduced by 32.4%compared with the speed of 40km/h and the maximum squeezing force is reduced by 27.7%.The initial releasing speed is higher,the maximum impacting force is reached faster.With the decreasing of initial braking speed,the maximum squeezing force is more and more small.The maximum squeezing force of initial braking speed 50km/h is reduced by 32.3%compared with the speed of 70km/h.The initial braking speed has little effect on the maximum impacting force.With the increasing of brake pipe pressure reduction,the coupler force is more and more big.The maximum impacting force of brake pipe pressure reduction of 100kPa is increased by 72.9%compared with the reduction of 50kPa and the maximum squeezing force is increased by 54.1%.The brake pipe pressure reduction is mainly affects the maximum coupler force but it has a week influence on the appear moment of maximum coupler force.Compared to configure brake-failed vehicles in the back of the first control locomotive,it can effectively reduce the maximum coupler force to configure the brake-failed vehicles near the front of the first control locomotive.The brake-failed vehicle configuration has little influence on the maximum coupler force at the rear position of the second locomotive.In this paper,by simulating the longitudinal dynamics of the 20,000-ton heavy haul train,it provides a powerful tool for reducing the longitudinal impulse of the train and a basic data for the configuration of the brake-failed vehicles.