Prediction And Experimental Study On Wheel Tread Wear Of High-speed Railway Train

In recent years,China's high-speed railway is in the stage of rapid development.Because of the improving running speed,the shorter workshop and the higher traffic density,the interaction between wheel and rail becomes more intense.The wheel wear and contact fatigue becomes common,which not only affects the ride comfort,but also threatens the safe operation of trains.Therefore,it is significant to study the wheel wear problem to reveal the wheel wear law and predict the wheel wear.Reprofiling wheel tread timely can prolong the service life of the wheel and reduce the operation cost of the vehicle.In this paper,the wheel tread wear of the Electrical Multiple Units(EMU)was studied.By tracking and testing the running trains,the wheel tread wear law has been analyzed and summarized.The wheel-rail finite element models(FEMs)were established to carry out contact calculation and the correctness of simulation was verified by the wheel-rail contact test.The friction work based on finite element contact was proposed to predict wheel tread wear.The main contents and conclusions are as follows:(1)The high-speed train wheels were tracked and tested by the wheel-rail profile-measuring instrument,and the worn wheel profiles under different operation mileages were analyzed.In a reprofiling period,the wheel tread wear can be divided into two stages,namely early rapid wear and mid-late stable wear.With the increasing running mileage,the wear rate of wheel tread increases and the reprofiling period decreases gradually.(2)The standard and worn wheelset-rail three-dimensional FEMs were established,and the working conditions were exerted,such as traction,axle load and lateral displacement.Compared with results of the standard model,the value of Mises stress of the wron model increased,and the maximum point was closer to the surface.The contact pressure between wheel and rail increased obviously.The contact spots were closer to the inner gauge and the sliding area occupied a larger area.The maximum values of node relative displacement and longitudinal friction were shifted to the inner edge of the flange.(3)The wheel-rail test rig was built and the wheel and rail samples were obtained by wire cutting to carry out contact tests.It was turned out that the shape and area of the contact spots by simulation coincided with the test results on the whole,which proves that the calculation by FEM can correctly simulate the actual contact state between wheel and rail.(4)Based on the physical meaning of work,the longitudinal friction force and the relative displacement at the contact spot node were multiplied to obtain the node friction work.Then,the node friction work was superimposed along the train running direction to obtain the wheel tread friction work.(5)A method of calculating wheel tread wear based on the FE friction work was proposed to predict the wheel tread wear and the worn profiles.The wheel tread wear was obtained by multiplying the wheel tread friction work with the wear coefficient and the friction times.(6)The simulation data of standard model and worn model were used to calculate the wear amount and obtain the predicted wheel profile respectively.It is found that the predicted profiles were basically consistent with the measured profiles,and the results of the worn model were closer to the real.It is reliable to calculate the friction work by FEM proposed in this paper.In order to get more realistic results,it is necessary to update profiles to predict the wheel tread wear.