Research On 120-Cars Unit Train Brake Performance Simulation

Type 120 air brake is main type brake of China Railway wagon at the present time. Since the 120 air brake put into use,the brake performance is more and more stable after nearly 20 years of improvement.However, with the increase of the running speed and use of strength, the 120 air distribution valve exposed many problems, and caused a lot of trouble for the department of daily maintenance.With the increase of vehicle use intensity, resulting in 120 air distribution valve action frequently, the main valve failure of 120 air distribution valve has occurred sometimes. In this respect, simulating the brake performance by the method of establishing the mathematical model of the train braking system is very necessary.First of all, determine the research object, analyze 120 air brake system structure, the mechanism, and the feature in unit of freight car braking system.Then, analyze of mechanism of the key components of the 120 type air distribution valve, to establish the mathematical model of the core components. The simulation is studied by combining the mathematical model with AMESim software, and the mathematical model is derived and analyzed.Secondly, analyze the stress of 120 air distribution valve core components of the mechanism and the influence of each chamber pressure changes related to the movement and effect of the piston. The research of the basic principles of the whole set of 120 air distribution valve provides a theoretical basis for a simplified mathematical model, and finally the theoretical foundation is laid for the establishment of a reasonable set of 120 air distribution valve model.Thirdly,the gas path module model are defined according to the set of 120 air distribution valve action principle. Simplify the mathematical modeling of local pressure reduction valve and the accelerating release valve according to the mechanism.Then, establish a set of 120 air distribution valve mathematical model combined with gas module model. Then, the simulation data and test data are compared to verify set of 120 air distribution valve simplified model is correct and reasonable.Forthly, the model of 120-cars unit train brake system is established, then the marshalling 60 cars,80 cars,100 cars,120 cars braking system are put into simulation analysis. Calculated the initial charging conditions, different pressure reduction braking condition and different relief conditions of different marshalling number.The results include different conditions of initial charging time, braking velocity, brake cylinder pressure, alleviate velocity and inflation time.The simulation data and test data are compared and then make the error analysis. And also analyze the marshalling car number,pressure reduction amount and other factors on the braking velocity and alleviate the velocity effects.Finally, the simulation of low pressure environment of 120 cars brake system, obtained the performance parameters of the braking system under low pressure environment. The calculation results are compared with the standard atmospheric pressure environment.