Research On Wheel-Rail Wear Based On Three-dimensional Finite Element Model

In recent years,high speed and heavy load of trains is being a tendency of the railway transportation and wheel and rail wear which is a kind of inevitable damage happened in the running time of the train is becoming more and more serious.In order to do better in railway operation and maintenance,it is urgent to carry out further study on the current wear law of railway and provide the technical support to the relevant departments who can make the targeted plan of repair.In order to discover the impact of wheel-rail material hardness matching ratio on wheel wear,a test of rolling contact of wheels was carried out at the Jinhua Institute of China Academy of Railway Science.The wheel samples were taken off and cleaned every time when it rotated ten thousand cycles,then using electronic balance to weigh its mass loss which is called as abrasion loss;Using the self-made small wheel polygonal wear measurement equipment to measure the shape of the sample that was named as polygon wear.Taking the wheel-rail samples whose hardness matching ratio is 0.95 as the research object.It was found that the abrasion loss of the sample is 0.176g per ten thousand cycles and the shapes of the samples were shown as 16-order polygon obviously.Hypermesh is applied to define 2D and 3D finite element model of wheel-rail rolling contact transient analysis,after that loading the working conditions of small scale test apparatus to the model.An explicit dynamic analysis program,LS-DYNA,is used to solve the problem of rolling contact transient analysis.An implicit-explicit sequence analysis algorithm is applied in calculating the stress and wear of the wheel after considering the influence of prestress of the model.It is assumed that the abrasion coefficient of wheel-rail in this working condition is 1,then comparing the calculated values from FEM simulation with experimental values for getting the real value of abrasion coefficient which is 3.9×10-5.In order to analyze the change rule of wheel-rail wear under different working conditions,we set up two groups of models,one group includes the wheel-rail models with slip rate of 5%,1.5%,1%and the other includes 16-order out-of-round wheels models with amplitude 0.014mm and 0.02mm.The results show that the wear of the wheel can be obtained by using the wheel-rail wear tester,and the numerical analysis of the wear value can be obtained by the transient analysis of the rolling contact of the wheel and rail combined with the 3D finite element model.It is a practical and usable research method to calculate the wear coefficient of the wheel and rail under the test condition from back to front.The wear coefficient of the wheel-rail specimen is found to be 4 x 10-5 in the frictional wear test and the 16th-order polygon wear of the wheel is also shown after 60,000 rotations;the change of wheel wear follows the change of wheel-rail slip rate,with a linear increase.As to polygon wear,the wear value at the sine wave peak is much smaller than at the wear value.The railway operation and maintenance department can use the above numerical simulation method to obtain the wheel repair distance for timely maintenance.