Wheel-rail Friction Work Theory And Wear Prediction Based On Contact Finite Element Method

Metro is an important tool for urban passenger traffic today,with the rapid development of the metro industry in the world today,the problem of wear between wheel and rail is also increasing;the problem of wear will lead to changes in the profile of the wheels and rails,reduce the stability and safety of the trains,the service life of various components,increase the operating costs of the railways,and may even lead to derailment;if an efficient and accurate wear prediction calculation method is established,it can predict the cumulative wear amount of rails and the distribution pattern of rail worn profile after a certain number of wheels pass qualitatively and quantitatively,then the rail worn profile,replacement cycle,etc.can be accurately estimated,this is of great significance for the development of the metro industry.This article focuses on the gradual and prominent wear problems in the development of the metro industry,analyzes and summarizes the existing research content,a finite element calculation model for wheel-rail rolling contact was established to explore the influence of factors such as traction or braking force,axle weight,and lateral displacement on wheel-rail contact;a frictional work calculation method based on the finite element method is proposed to explore the evolution,development and laws of rail worn profiles.The main research contents and results are as follows:(1)Established a finite element model of subway rolling wheel-rail contact model and conducted contact analysis.Using the Beijing subway standard and measured abrasion of the rear wheel-rail profile,a finite element model of wheel-rail rolling contact model was established,the influence of traction,braking force,axle load,and lateral displacement on the wheel-rail contact was explored,it was fully explored the contact state,contact force,surface and internal stress distribution and changes in the situation,and compared the standard and wear type wheel-rail contact calculation results similarities and differences.(2)A new frictional work calculation method is proposed,which provides a new theoretical basis for rail wear prediction.Based on the results of finite element calculations,the frictional work calculation method based on the finite element method is proposed: the frictional work of each node on the contact patch is equal to the product of the friction at the joint and the relative displacement of the contact point;the wear amount and frictional work of each node is linear relationship.The new frictional work calculation method is characterized in that it is directly related to the frictional force and relative displacement at the contact point and is in accordance with the physical meaning of the work;the finite element model can be used to calculate the contact patch frictional work at any contact position;and explore the distribution of friction work on contact patch;the contact-friction force and relative displacement distribution law of the contact finite element calculation can reflect the axle load,the friction coefficient between the wheel and rail with the speed,and the influence of the wheel-rail profile;the friction function based on the finite element method provides the wheel-rail wear prediction a new theoretical method.(3)Using the new frictional work calculation method to predict the wear of the rail,and explore the development rule of rail wear.A new calculation method for wear volume superposition was developed using the new frictional work calculation method,and the cumulative wear,wear depth,and worn profile development of the rail top were predicted.The study found that using the frictional work calculation method,which is based on the FEM,to predict the amount of rail wear and the worn profile of the top rail is more consistent with the measured profile;the cumulative wear of the rail is largest at the inner side of the rail head near the gauge angle;cumulative wear and wear depth increase approximately in proportion to the number of wheel passes;the frictional work results which using the worn wheel-rail profile are flatter and closer to the measured profile.