制动工况下重载货车车轮扁疤对轮轨振动响应分析

Analysis of wheel rail vibration response caused by wheel flat of heavy freight vehicles under braking conditions

随着我国重载铁路的发展,重载货车轴重不断增加,车轮扁疤问题也日渐突出,该问题会导致轮轨动载荷急剧增大。建立了重载车辆-轨道刚柔动力学模型,在考虑了重载货车不同制动工况下,探究车轮扁疤对轮轨之间垂向冲击力和纵向蠕滑的影响,并进行了扁疤限值计算。结果表明,车辆的P1和P2力随着扁疤长度和速度的增大而增加,且紧急制动工况下大于正常制动工况。空车状态下轮轨垂向力远远小于重车状态,但在扁疤的作用下空车状态下的垂向轮轨力产生的波动会更大。车辆进行制动会导致纵向蠕滑率和纵向蠕滑力发生改变,同时在扁疤的作用下纵向蠕滑率和纵向蠕滑力都会产生波动,扁疤越大波动幅度越大。根据标准中的轮轨垂向力和轮重减载率的限值,对车辆在不同工况下进行扁疤限值计算,结合空重车以及制动工况,得到重载货车扁疤限值为38 mm。该研究将为重载货车运维提供相关指导。

With the development of heavy haul railway in China,the axle load of heavy haul freight vehicles is increasing,and the problem of wheel flat is also increasingly prominent,which leads to dramatic increase in dynamic wheel rail loads.In this paper,a rigid-flexible coupling dynamic model of heavy haulfreight vehicle-track was established,and the influence of wheel flat on vertical force and longitudinal creep between wheel and rail was investigated under different braking conditions of heavy haul freight vehicles,and the limit value was calculated.Results show that the P1 and P2 forces of the vehicle increase with the increase of the length and speed of the wheel flat,and the emergency braking condition is greater than the normal braking condition.The wheel/rail vertical force of the empty car is far less than that in the load car,but the wheel/rail vertical force fluctuation of the empty car will be greater under the effect of the flat.On the other hand,braking of the vehicle will lead to changes in the longitudinal creepage and the longitudinal creep force.At the same time,the longitudinal creepage and the longitudinal creep force will fluctuate under the action of the wheel flat.The larger the wheel flat,the greater the fluctuation.According to the wheel/rail vertical force and wheel load reduction rate specified by the state,the wheel flat limit value of the vehicle under different working conditions was calculated.Combining the empty and load vehicles as well as the braking conditions,the limit value of wheel flat of the heavy haul freight vehicle was determined as 38 mm.The study will provide relevant guidance for the operation and maintenance of heavy haul freight vehicles.