Influence Of Different Wind Fields On The Safety Of High-speed Train Operation On Embankment

With the rapid development of high-speed railway in China,various embankments with different structures have been formed.The complexity and diversity of embankment structures make the aerodynamic loads of high-speed trains constantly change.The speed and direction of nature’s stroke will always change with the change of surrounding terrain.Therefore,it is necessary to study the influence of embankment structure on aerodynamic characteristics of high-speed trains under different wind fields to ensure the safety of trains.In the present thesis,the aerodynamic simulation models of high-speed trains running in different types of embankments are established,the influence of embankment structural parameters on the aerodynamic performance of high-speed trains under the action of crosswind and abrupt wind is studied,and the influence of crosswind and abrupt wind on the aerodynamic performance of trains is comparatively analyzed.The dynamic model of the train is established.Based on the excitation obtained by aerodynamic simulation,the safety indexes of the train in different wind environments are analyzed,and the influence of embankment structure on the running safety of high-speed trains is compared.The results indicate that:(1)In crosswind environment,the aerodynamic characteristics of trains on embankment are significantly different from those on flat land.The lift,lateral force,rolling moment and shaking moment of the train running on 2m embankment are increased by 72%,44.2%,23.8% and 18.2% respectively compared with those of the head train running on flat ground.(2)Different embankment structures have obvious influence on the aerodynamic performance of the train:(1)The lift,lateral force,rolling moment and shaking moment of the head car with the embankment height of 2m are reduced by 49%,52%,97% and 92% respectively compared with that of 8m.(2)The rollover moment decreases with the increase of embankment angle,while the nodding moment and shaking moment increase and then decrease in the range of 24 ～ 35.(3)Under the action of sudden wind,the height and inclination of embankment are unchanged,and the aerodynamic force of train increases with the increase of vehicle speed.The lift,lateral force,rolling moment and shaking moment of the head car with a speed of 350km/h increased by 57%,27%,111% and159% respectively compared with that with a speed of 200 km/h.(4)Compared with crosswind,abrupt wind has greater influence on the aerodynamic characteristics of trains.(1)When the embankment height is 4m,compared with the crosswind of 13.8m/s,the lift,lateral force,rolling moment and shaking moment of the head car increase by 25%,90%,27% and40% respectively.(2)Compared with the crosswind wind,the fluctuating values of all aerodynamic forces are above 50% when the embankment inclination angle is 35 under sudden wind.(5)With the increase of vehicle speed,the safety factor increases.When the vehicle speed is greater than 300km/h,the wheel load shedding rate approaches the limit value of safe operation.The safety factor of trains in sudden wind field is larger than that in crosswind,which indicates that trains are more prone to accidents in sudden wind.(6)When the height of the embankment is constant,the inclination angle of the embankment increases,the safety factor is smaller,and the safety of the train is higher.The inclination angle of embankment is unchanged,the height of embankment increases,and the safety of train decreases.