Research On Contact Mechanism And Material Removal Characteristic Of The Serrated Contact Wheel In Rail Grinding Using Abrasive Belt

As the service life of the railway increases,various damages will appear on the surface of the rail,and effective grinding of rails plays a vital role in prolonging the service life of rails and ensure the safety of train operation.In recent years,with the continuous development of the national railway system,a larger amount of railway repair work requires more efficient grinding operations.As a new and high-efficiency grinding method,abrasive belt rail grinding(ABRG)has come into people’s field of vision.It relies on the complex contact between the contact wheel,the belt and the rail to achieve flexible and efficient grinding of the rail surface.In the actual grinding operation,the serrated contact wheel has higher material removal characteristics than the flat contact wheel belt grinding.But the current research has not revealed the mechanism of the cause of this characteristic.Therefore,this article will conduct a detailed investigation on the contact mechanism and material removal characteristics through a combination of simulation,modeling and experiment of the serrated contact wheel in rail grinding.The main research contents are as follows:Establish a parametric three-dimensional model between the serrated contact wheel and the rail.Through ANSYS Workbench software,the finite element simulation of contacts under different parameter changes is established,explore the influence of parameter changes on the maximum contact stress,contact area and rubber indentation depth.And the structural parameters of the serrated contact wheel include helix angle,serrated ratio,the number of teeth,and the groove depth.The non-structural parameters include the grinding pressure and the rotation angle of the contact wheel.Through the analysis of the simulation results,it is found that when the parameters change,the maximum contact stress,the contact area and the rubber indentation depth change in accordance with the certain rules.On this basis,a theoretical model of the contact between the serrated contact wheel and the rail under static pressure is established.The mathematical model of the contact area is solved by the expansion of the Hertz contact theory and the contact geometric relationship.Next,calculate the regression equation of the maximum stress in the contact area through the multiple nonlinear regression method,and then achieve solving the pressure distribution in the stress concentration area,and combine the ellipsoidal pressure distribution area to finally synthesize the pressure distribution model.Finally conduct the contact static pressure test platform experiment,use the LLLW pressure film of FUJIFILM to record the experiment,then extract the data,calculate the data of the model at the same time,and verify the accuracy of the model through the result comparison.A model of material removal for serrated contact wheel rail grinding is established.Through the analysis of the model,a hypothesis is raising for the reason why the serrated contact wheel has a higher material removal rate than the flat contact wheel.And then design and conduct material removal experiments on the grinding experimental platform.The theoretical and actual ratios of material removal rates of the serrated contact wheel and the flat contact wheel under different pressures were compared and analyzed to verify the correctness of the hypothesis.Finally,the reason for the high material removal characteristics of the serrated contact wheel in abrasive belt rail grinding is obtained.The experiment also compared the vibration,noise,current and roughness performance of the serrated contact wheel and the flat contact wheel during the grinding process,explored the advantages of serrated contact wheel in other grinding characteristics.