Dynamics Analysis Of200Km/h Locomotive Under Braking Conditions

To adapt to the rapid development of China’s national economic situation, the capacity and efficiency of railway transport must be improved, therefore the speed of locomotive need to be enhanced. At this stage, the speed of our country independent developed high speed locomotive has reach200km/h. As the speed increases, the dynamics performances become worse. In the past, the research of locomotive dynamics performance mainly considering the working condition under constant speed and traction, and rarely considering the condition under braking. Therefore this article focuses on the200km/h locomotive dynamics performance under braking condition, and the influence of the major suspension parameters affect the dynamics performance.A200km/h locomotive model with Co-Co axle arrangement is established by multibody dynamics software SIMPACK. The main structure and suspension parameters are introduced. The corresponding differential equations of motion and track irregularity are given in this paper. Then the comfort performance, lateral stability, and the curve negotiation performance under constant speed condition are researched. The results show that the200km/h locomotive has a good dynamics performance, the linear critical speed is higher than500km/h, and the non-linear critical speed is between250km/h and300km/h.To simulate the braking condition a constant braking torque is applied to the locomotive’s axle. The influence of coupler is not considered. By comparing the vertical and lateral ride index, lateral wheel-set force, wheel unloading ratio, wheel derailment ratio between the conditions under constant speed and braking, the influence of braking torque to200km/h locomotive is researched. The results show that the influence to the safety of locomotive on straight line is small. But when the locomotive running at low speed and under braking, the vertical vibration is increased severely, and the vibration frequency is also increased. When braking on curve, the lateral and longitudinal creep force is changed making the curve negotiation difficult.Finally, the influences of primary and secondary suspension parameters to dynamics performances of locomotive under braking condition are researched. The results show that the influence of primary and secondary vertical stiffness and damping to the vertical ride index of locomotive is small. Increasing the primary lateral stiffness makes the curve negotiation difficult. Increasing the secondary longitudinal stiffness is conducive to the curve negotiation.