Influence Of Alignment Parameters On Dynamic Performance Of Heavy Haul Train With Emergency Braking

The damage to the railway line geometry and track structure of railway lines is aggravated.The cause of this phenomenon is that the axle weight,the length of marshalling and the weight of traction of heavy haul train are increasing because of the extensive application of heavy haul railway transportation and the rapid development of technology.The dynamic performance of heavy haul train will deteriorate under the emergency braking and other unsteady state conditions.If the heavy haul train passes the complex route conditions at this time,the severe longitudinal force between the heavy haul freight cars will make the train in the bad running state.In order to make the heavy haul train well match with the route system,ensure the safety of the heavy haul train,and provide reference for the heavy haul railway line design,it is very necessary to study the influence of alignment parameters on dynamic performance of the heavy haul train with emergency braking.First,Multidimensional heavy haul train-route hybrid dynamic model was established.The model was based on multi-body dynamics and longitudinal dynamic analysis of train and was built by the UM multi-body dynamic analysis software.The model could adopt a hybrid modeling method,which one-dimensional train longitudinal dynamic model and three-dimensional multi degree of freedom vehicle dynamic model were used.In the model the dynamic behavior of train in three directions: longitudinal,lateral and vertical directions was considered simultaneously,so the model could better simulate the dynamic performance of the train under the unsteady state.Secondly,the reasonable alignment parameters were selected for the simulation calculation according to the condition of the existing railway and relevant specifications.First,the calculation results of dynamic parameters were obtained by simulation.In this simulation,the heavy haul train with emergency braking was under different plane parameters of railway line including curve radius,the ultra high and the relaxation curve.The results shown that the dynamic performance of the vehicle is improved with the increase of the radius of the curve;when setting an equilibrium ultra high or deficient superelevation,the derailment coefficient and rate of wheel load reduction of the vehicle are small,which is beneficial to the safety of the vehicle and can make the two rail wear evenly;with the increase of the transition curve length,the dynamic performance of the vehicle is improved.Finally,the paper further simulated the heavy haul train with emergency braking which was under different alignment parameters combine with horizontal and longitudinal section conditions,including the combination of plane circular curve and ruling grade,circular curve and vertical curve.The results shown that the dynamic performance of the vehicle becomes worse with the increase of the ruling grade;the difference between gradients has little effect on vehicle safety,when designing the railway line,the line with large slope difference and small radius curve is still safe when calculating;The influence of the difference between gradients on wheel rail lateral force is obvious,with the increase of the difference between gradients,the lateral force of wheel and rail basically increases linearly;It is similar to the effect of plane curve radius on the dynamic performance of emergency braking train,in the section combined with horizontal and longitudinal conditions,with the increase of the radius of the curve,the dynamic performance of the vehicle is improved.