Influence Of Coupler-Draft Gear On Longitudinal Impulse Of Train

With the sustained and rapid development of our national economy, the demand for bulk cargo such as coal and iron ore is in the sudden increase. In order to satisfy the requirements of cargo transportation, increasing the length of the train formation is the main method to improve the railway transport capacity. But the operation of heavy haul train will appear the sharp deterioration of the performance of train longitudinal dynamics inevitably, leading to the rapid increase of coupler force, this will seriously affect the safe operation and restrict the further promotion of train heavy transportation process. Therefore, reducing the maximum coupler force become a primary problem to operate heavy haul train.There are many factors affecting the coupler force, including the marshaling vehicles, breaking characteristics, coupler-buffer device features and so on, but the coupler slack and buffer performance is the most direct influence on coupler force. In this paper, combining air brake and longitudinal dynamics synchronize simulation system, the simulation researches the influence of the coupler force which made by draw bar and the MT-2 type buffer stiffness so that can seek ways to reduce the maximum coupler force of train.Firstly, it studies the effect of the impact of draw bar on coupler force through the simulation system. In a simulation model, single 10000-ton train at the initial velocity of 80km/h use in full braking application, anayze the impact of draw bar for coupler force when at the difference of the initial velocity, the coulper slack, the marshaling vehicles and the pipe decomressions. The results prove : in different factors, maximum coupler force has reduced with draw bar. Then it analyzes the influence made by different buffer stiffness and its change at different positions through simulation, in this way, in the case of lessening coupler force, it is better to increase the head buffer stiffness and reduce the rear at the same time than the whole train lower stiffness, but because of increasing the head buffer has a small effect on reducing the maximum coupler force, considering saving economic cost meanwhile, reducing the rear buffer is the optimization program. Finally, it follows that at the same time to use draw bar and optimization program of buffer stiffness distributed is adopted simultaneously, the effect is more significant : when the single 10000-ton train are in full braking application and emergency braking application, the maximum coupler force with draw bar and optimization program of buffer stiffness distributed is 527.3kN and 541.6kN respectively, comparing with common coupler and original stiffness, it decreases 117.3kN and 97.9kN separately; for 20000-ton train are in full braking application and emergency braking application, the maximum coupler force with draw bar and optimization program of buffer stiffness distributed is 541.6kN and 794.6kN respectively, comparing with common coupler and original stiffness, it decreases 284.7kN and 331.6kN separately.