Influence of Brake Characteristics on Longitudinal Impulse of Train

Referring to excessive longitudinal impulse of Da-Qin heavy haul trains in practice,co-simulation of air braking characteristics based on gas flow theory and train longitudinal dynamics based on rigid body kinetics are used to study the effects of braking system characteristics(uniformity of brake propagation,brake propagation speed and pressure increasing speed of brake cylinder,etc.)on longitudinal impulse.The results show that under the conditions of same brake propagation speed,train longitudinal impulse of uniform and non-uniform brake propagation are basically consistent,and brake propagation speed affects coupler force significantly.The faster the brake speed is,the smaller the coupler force is.Under the conditions of same stopping distance with the convergence of front and rear vehicle′s brake cylinder pressure curves,longitudinal impulse is reduced significantly,and the locations of maximum coupler force are moved towards the rear of train.