Effect Of Wheel Abnormal Wear On Dynamic Derailment Of High Speed Train

With the accumulation of operating mileage and time of high-speed railway in our nation,the wheel damage problem of partial train has arisen successively.The change of wheel profile will affect the wheel/rail relation and interaction.And vehicle dynamic performance,including the safety,hunting stability etc.will be reduced according.If a high-speed train derailed,a catastrophe of passengers and transportation may be brought.Therefore,it is essential to study the effect of wheel damage problem which occurred in the operation of high-speed train on the dynamic derailment safety.The flexible-rigid coupled model of high-speed train was used to carry out the numerical simulation in this paper.In order to simulate the process of derailment in the curve section,the lateral load which caused derailment was applied at the center of gravity of the vehicle.The dynamic behavior of the wheelset and the interaction of wheel and rail was analyzed.The function of relative traverse displacement between the wheel and rail and the derailment risk coefficient are introduced to judge the degree of derailment danger.The influence of wheel profile damage on the dynamic derailment of high-speed train is analyzed in detail by using the appropriate dynamic derailment evaluation method.The effect of the roll moment,the lateral force acting position and the running speed to the dynamic derailment of the standard wheel and the wear wheel are studied respectively.Some results and conclusions of this paper are listed as follows:(1)In the three wear forms,including the wheel tread wear,the same phase tread deflected wear and the reverse phase tread deflected wear,the hunting nonlinear critical speed of the same phase tread deflected wear wheel is the lowest,while the reverse phase wear wheel is the highest.The amplitude of the track irregularity not only significantly reduces the nonlinear critical velocity,but also increases the lateral displacement and velocity extremes of the wheelset during hunting movement.And the influence on the hunting stability in the straight section is remarkable.(2)The influence of flange wear is the most significant on the dynamic derailment of high-speed train in the range of wheel tread wear,flange wear,deflected wear and wheel polygon calculated in this paper.Especially when the amount of flange wear is 3.5 mm.While the effect is not obvious when the amount of tread wear is less than 1.4 mm.And in the same derailment condition,derailment occurs firstly in the condition of the flange wear wheel and the same phase flange wear.The impact of the dynamic behavior of same phase flange wear wheelset is slightly larger.(3)It is recommended to use the wheelset lateral displacement and the derailment risk coefficient instead of derailment coefficient and wheel unload ratio to judge the effect of wheel wear on the derailment safety of high-speed train.In evaluating the impact of wheel polygon on the derailment safety of high-speed train,it is recommended to adopt the derailment coefficient and the wheel unload ratio to judge.And the wheelset lateral displacement and the derailment risk coefficient are supplemented to assess.(4)With the increase of the speed,the maximum value of lateral force causing wheel off the rail decreases and it is easier to derail.The worn wheel performs more sensitive.While the maximum value of roll moment increases and it is less prone to derail.And the standard wheel is more prone to derail than worn wheel on the effect of the same roll moment.