Design Method Of Grinding Target Profile Of Over-worn Rail For Heavy-haul Railway

As heavy-duty railway technology is more and more widely used in our country,heavy-duty trucks with both timeliness and capacity effectively alleviate the contradiction between domestic railway freight supply and demand.Heavy-duty railways will inevitably produce a large number of excessively worn rails with severe rail head wear during operation,affecting the normal wheel-rail relationship,and even causing serious safety accidents such as train derailment.To deal with the abnormal wear of the rail,the maintenance of the rail profile by grinding can effectively solve the rail disease and prolong the life cycle of the rail.Grinding and maintenance of excessively worn rails requires grinding profile design based on on-site measurement conditions.However,the existing profile design methods are mostly optimized based on the standard profile of rails,which are difficult to apply to worn rails.Therefore,it is urgent to find solutions for excessively worn rails.The grinding profile design method for worn rails to extend the service life of the rails.Aiming at the excessive wear of rails on heavy-duty lines,this paper proposes a rail grinding profile design method characterized by the arc tangent point,which is solved by integrating genetic annealing algorithm to obtain the optimized rail profile.The research results are as follows:1.Introduced wheel-rail contact geometry,contact mechanics parameters,and vehicle system dynamics solution methods,established wheel-rail static contact model,rail wear model,vehicle-track system dynamics model,and verified the dynamics model,which is the rail profile The shape optimization design establishes the theoretical basis.2.In order to obtain the rail profile representing the curve section of the heavy-duty line,the least squares distance method,arithmetic average method,weighted average method and scatter point reconstruction method are used to obtain four representative rail profiles,and the Pearson correlation coefficient is used.,Kendall rank correlation coefficient and Spearman rank correlation coefficient to obtain the correlation coefficient value of the probability distribution curve of the representative profile and the measured profile contact point of the four algorithms.3.Analyze the structural elements of rails at home and abroad,propose a rail profile design method characterized by arc tangent points,integrate simulated annealing algorithm as an optimization method,and reduce rail wear prediction and rail grinding and cutting removal as the optimization goal.Boundary range,profile curve unevenness,derailment coefficient,and wheel-rail lateral force are used as constraints.The profile optimization results show that the R_opt optimized profile is located below the R_wear wear profile curve and can be achieved through limited polishing.The metal cutting volume of the R_opt optimized profile is 0.35 times that of the actual polished profile of R_real-gri.The amount is significantly reduced.Perform wheel-rail static contact,dynamics and finite element analysis on the R_opt optimized profile and the R_real-gri actual polished profile.R_opt profile has better wheel-rail matching contact,more reasonable equivalent taper curve,wheel-rail lateral force and wheel load reduction under heavy vehicle conditions;wheel-rail lateral force under empty vehicle conditions Significant decline,the wheel load shedding rate is slightly reduced,and the vehicle body lateral,vertical vibration acceleration,wheel-rail vertical force,wheelset lateral displacement is relatively small.Combining heavy and empty vehicle conditions,the R_opt profile dynamic performance has not been significantly reduced,and it has better wheel-rail static matching performance.It is predicted that the amount of wear will increase slightly,but the amount of metal removal will decrease significantly,which can effectively extend the life cycle of the rail.