Research On Trafficability For Railway Turnout Of Six-axle And Broad-gauge Electric Locomotive

In recent years,with the rapid development of the China ’s railway transportation industry and the implementation of the " Going global " strategy,China ’s locomotive exports overseas ushered in new opportunities.However,due to the historical culture and technical differences,such as track and railway related technical standards,export locomotive development is also facing greater challenges.Today’s railway transportation is developing towards the direction of high speed and heavy load,and turnout belongs to one of the three weak links of the track components,which limits the speed of driving,affects the safety of operation,and determines the passing performance of railway.In view of this,it is of great significance to carry out the dynamic theory research of broad-gauge locomotive in turnout area.In this paper,the turnout trafficability of a certain type of wide rail locomotive is studied,which can provide a certain design theoretical basis and method for the export type broad-gauge locomotive and its operation.Firstly,the multi-body dynamics software SIMPACK is used to establish the coupling dynamics model of locomotive-turnout system according to the structural parameters of broad-gauge locomotive and the change of track section.The turnout model adopts two models: No.12 fixed frog turnout and No.18 movable turnout.In addition,in order to analyze the dynamic interaction between wheel and rail more accurately,the wheel model is flexible by ANSYS,and then combined with SIMPACK,the dynamic model of locomotive-turnout rigidflexible coupling system is finally established.Then the results of the locomotive passing through the turnout are analyzed,and the validity of the model is proved by mutual verification with the existing literature.Secondly,the simulation calculation and dynamic evaluation analysis of the straight and lateral reversals of the wide-track locomotive through switch No.12 and No.18 are carried out.The results show that:(1)The index parameters of the frog of the wheel-rail force,the coefficient of derailment,the load loss of wheel weight and the vertical dynamic load coefficient are obviously greater than that of the switch.(2)When crossing No.12 switch with 120 km/h straight reverse,the vertical force of wheel-rail reaches 350 k N exceeding the limit value,and the wheel weight loss rate reaches 1.The wheel-rail does not contact for a short time,but the duration does not exceed 0.01 s,and no derailment occurs.(3)When the vehicle speed is 120 km/h straight through No.12 and No.18 turnouts,the vertical force of wheel and rail,derailment coefficient,wheel load reduction rate and other index parameters,No.12 is about twice of No.18,the dynamic performance of the locomotive through No.18 is obviously better than No.12.Finally,taking Turnout No.12 as an example,the influencing factors of derailment in turnout area are studied.The results show that:(1)As the augment of friction factor,derailment coefficient and wheel lift increase obviously,and wheel rail friction coefficient should be kept at 0.36 ～ 0.53 to improve the critical limit of derailment;(2)Appropriately increasing the curve radius before entering the turnout can reduce the wheel-rail lateral and vertical force,and increase the safety margin through the turnout;(3)The crossing safety performance of widegauge locomotives can be improved when the lateral stiffness of primary suspension is 1.3 ～ 4.3 MN/m and the vertical stiffness of primary suspension is4 ～ 6 MN/m.(4)The lateral stiffness of the secondary suspension is in the range of 0.1 ～ 0.3 MN/m,which is beneficial to the trafficability of the lateral turnout and reduces the risk of derailment.The vertical stiffness of the secondary suspension has little effect on derailment.The optimal speed of the locomotive passing through the turnout is 30 ～ 50 km/h.