Research On The Contact State And Grinding Pattern Of Abrasive Belts With Rails Under Torsional Angle

With the rapid development of rail transport in China,the maintenance process for rails is becoming increasingly important.Rail grinding is an important means of removing rail surface damage and repairing the rail profile.Compared to traditional grinding wheel grinding,rail abrasive belt grinding technology has the advantages of high grinding efficiency,low temperature in the grinding area and low grinding noise,so in the actual grinding operation abrasive belt grinding is used in more and more scenarios.In order to remove material from the rail surface at different locations,several abrasive belts need to be arranged at different deflection angles and the combination of deflection angles and process parameters is the grinding mode.In order to improve the sanding quality and efficiency,this paper focuses on the optimisation algorithm of the sanding pattern.Firstly,the theoretical formulae for the material removal volume parameters are derived based on the projected geometric relationships on the rail cross-section and the contact wheel cross-section respectively during constant cutting depth grinding with abrasive belts;the three-dimensional material removal depth model is obtained by establishing a discrete point matrix of the rail surface and contact wheel circumference for the material removal area;the theoretical calculation results are compared with the numerical simulation results,and The theoretical calculation results are compared with the numerical simulation results,and the influence of the position parameters on the material removal volume is investigated.Secondly,the mathematical relationship between the displacement of the contact wheel and the contact pressure is derived to solve for the tension force on the abrasive belt when the contact wheel is twisted and polished at a certain angle;the stress distribution model in the contact area between the contact wheel and the rail is obtained according to the Hertzian contact theory;the contact stresses obtained from the simulation model and the experimental set-up are compared with the theoretical contact stresses to verify the validity of the theoretical model.The validity of the theoretical model is verified.Then,combining the stress distribution model and the single abrasive material removal model obtained in the previous paper,a multi-row abrasive material removal model for abrasive belt grinding is established;the effects of contact wheel deflection angle,torsion angle and displacement on the material removal profile,material removal area,rail contact width,contact wheel contact width and contact pressure are investigated.Finally,the calculation method of rail profile after multiple abrasive belt grinding is derived,and the quality evaluation index and roundness evaluation index of rail profile after grinding are established;combined with the differential optimisation algorithm,the remaining area between the profile after grinding and the target profile is used as the objective function to generate the ranking order of deflection angle;taking a research line as an example,two grinding modes are generated while the contact wheel twist angle is different,and the The grinding pattern is predicted and evaluated under the grinding pattern,and the influence of the angle of twist on the grinding pattern is investigated.