The Analysis Of Parameters' Affection On The Train Longitudinal Dynamics

Along with the sustained, rapid and stable development of China's national economy, the railway concerned as the main artery of national economy. Since 2006, the Datong-Qinhuangdao line opening line of the 20 000 t train, till 2008, China's railway transportation volume reached 340 million tons, Due to the impact of financial crisis, every 3.3 million for the 2009, have declined, but overall, the development of heavy-load transportation has become the direction of development. The rapid development of railway heavy-load transportation put forward more severe challenges to train longitudinal dynamics research.Over the years, the study on train longitudinal dynamics mainly adopts operating test methods, occupying large amounts of locomotive and rolling equipment and the necessary test line, a costly waste of time and also restricted by the number of tests and dangerous working conditions, there are great limitations. Computer simulation methods can option for more information content, high risks and low cost advantages. In this paper, air brake system and longitudinal dynamics system combined simulation software can simulate the braking performance and longitudinal dynamics performance of different compositions, brake pressure and braking condition, and it can real-time dynamic display of the train operation process, effective simulation of locomotive vehicle gear train system parameters, technology, organization, lines and braking characteristics of the train operation process, to realize the study and prediction on train longitudinal dynamics performance.Using the air brake system and longitudinal dynamics system combined simulation software, with 10000 tons (1 locomotive + 100 vehicles) train compositions, for example, analyses the mechanism of train longitudinal impulse during braking condition, clear the coupler force characteristics. Analysis the influence of braking conditions, line conditions, coupler gap, brake shoe friction coefficient and braking characteristics on longitudinal impulse. Discussed the influence of train driver operation mode, line conditions, rail surface conditions and the initial state of coupler on the start-up performance. Then analyses the compositions of longitudinal impulse of brake and release condition, studies the influence of braking original speed, tube decompression and releasing speed on train longitudinal impulse.In braking process, the mechanism of longitudinal impulse formed together by the impact action and the squeezing action during train braking, the largest impact force occurs in the rear of the train, maximum squeeze pressure occurs near the middle of the train; Compared with common braking, emergency brake exacerbate the longitudinal impulse; Line gradient almost no influence on the longitudinal impulse; The bigger coupler slack, the bigger maximum coupler force, and the effect of coupler slack on impact force is greater than on squeeze pressure, the impact on the rear of the train is more significant; Brake friction coefficient has great influence on squeeze pressure, and less on impact force, the bigger Friction coefficient, the bigger squeeze pressure; We can control the train longitudinal impulse by changing the braking characteristics.In start-up process, the control mode has great influence on the initial stage of start-up performance; The smaller line gradient, the better start-up performance; Damp surface has adverse effects on start-up performance; The initial state of coupler has little effect to train start-up performance. In brake and release condition, the bigger braking original speed, the smaller largest coupler force; The bigger tube decompression, the bigger largest coupler force; Improve releasing speed, help to reduce the largest coupler force.