Study On Dynamic Performance Of Heavy Haul Rolling Stock And Geometric Parameters Of Curves In The Long Downslope Curve Section

Along with the increases of train length,axle load and the complexity of line condition such as curve section of long-down slope,the issues of train longitudinal impact,wheel-rail dynamic interaction and train running safety become increasingly urgent.It is extremely necessary to study the relationship between curve parameters and train dynamic performance.Based on the train longitudinal dynamics and vechile system dynamics theory,a mixed 10000t heavy-haul train model is established.Especially,three-dimensional vehicle connects with three-dimensional coupler and others among single train and three-dimensional vehicle are connected with draft gear system.The paper is devoted to studying the dynamic behavior of coupler and wheel-rail force and curve parameters as the longitudinal dynamic occurs on the curve section of long-down slope.Besides,the influence of curve radius,length of transition curve and superelevation on the dynamic characteristic of heavy-haul train is studied based on the combined train model.The main research results as follows:(1)The train longitudinal dynamic has various influences on the coupler swing angle and wheel-rail force of the rolling stock with the 1000kN of coupler force.Coupler swing angle increases up to 2-5 times and wheel-rail lateral force increases by 70-90 percent than response without coupler force.In addition,the growth of wheel lateral force up to about 10 times is the most significant.(2)The dynamic performance indexes including coupler swing angle,wheel-rail force,wear index and surface fatigue reach the maximum at the slow dot when emergency braking is applied to heavy haul train on the curve section of 13 per long-down slope.It turns out that running performance of the locomotive is worse than truck vehicle.Compared with idle running condition,wheel-rai]lateral force and derailment coefficient increase by 10-20 percent and the longitudinal dynamic has little effect on the wheel-rail vertical force which the growth is less than 6 percent.The wear index is influenced greatly that locomotive increases 1.5 times and vechile increases by 60 percent.Also the surface fatigue index of vechile rises by 66 percent more than locomotive’s.(3)It is effective to improve the performance and safety of heavy haul train by enlarging the radius of the curve and the length of transition curves and reducing the superelevation.The paper obtains:Reducing the radius could make the performance of heavy haul train to deteriorate rapidly along with the radius of the curve less than 1000m.However,the improcement of enlarging radius slows when the radius exceeds 1200m.As for the incluence of transition curve,decreasing the transition curve leads to the rapid increase of wheel rail interaction force in 150m,otherwise brings low effciency more than 150m.The performance of the rolling stock improves as the superelevation is smaller.Increasing the radius of the curve can effectively reduce wheel-rail wear and fatigue damage.The transition curve and superelevation change have little effect on the wear and fatigue.It is suggested that the radius is more than 1200m normally and 1000m under difficult conditions.It’s better that the length of the transition curve is not less than 150m.