| Reasonable wheel-rail profile matching helps to ensure driving safety,improve vehicle running quality,reduce wheel-rail wear and damage,and increase service life.At present,the wheel-rail profile matching is not the same in my country’s subway lines.There are many researches on the problem of wheel-rail profile matching on ordinary section lines,while the research on the turnout area is almost zero.Therefore,it is necessary to compare several common subway wheel profiles in our country to obtain a better wheel-rail profile matching combination;In addition,considering the complicated wheel-rail relationship in the subway turnout area and the urgent need to increase speed when passing through the turnout In addition to the problems of serious damage and short service life of curved switch rails,the research on the optimization of the rail profile of the existing subway turnout area in our country is urgently needed.In order to compare the matching performance of the wheel-rail profiles of different wheel profiles in the metro No.9 turnout area,the geometric characteristics of wheel-rail contact,the contact mechanical characteristics of wheel-rail passing through the turnout,the dynamic performance of passing through the turnout,and the wear and damage of wheel-rail were taken into account,and the traditional index comparison method was used to judge qualitatively and the improved analytic hierarchy process was used to compare and verify quantitatively.The comparison results show that when crossing the switch straight,the S1002 wheel matches the subway No.9 turnout with good performance;when the LM wheel matches the subway No.9 turnout,the performance is better when the LM wheel is matched with the subway No.9turnout.When the DIN5573 wheel is matched with the No.9 turnout of the subway,its performance is poor,whether it is straight or side turnout,especially in the wheel load transition section,the contact spot area is small when it passes the turnout and the maximum normal contact is great.The improved analytic hierarchy process also verifies this conclusion more comprehensively and accurately.In the actual operation of the vehicle,a larger rolling circle radius difference is beneficial to improve the ability of laterally passing through turnouts,but it is difficult to maintain the stability of passing through turnouts.The higher the conformal degree of wheel-rail profile,the smaller the normal contact gap between wheel and rail during wheel load transition,which is beneficial to reduce the contact stress during wheel load transition.By choosing the slope of wheel/rail profile to represent the profile conformity of wheel/rail profile,the relationship between the slope of wheel/rail profile and the radius difference of wheel rolling circle is deduced and established according to the geometric characteristics of wheel/rail contact,and the adjusted function curve of target rolling circle radius difference is given,according to which the rail profile of the whole rail head can be designed and by slicing it to form an optimized a sharp rail in the switch area.The optimized turnout switch has more reasonable contact mechanics characteristics,the stability of crossing is significantly improved,and the rail wear is reduced.Generally speaking,this newly designed turnout rail can effectively improve the turnout performance of metro vehicles and prolong the service life of rail in turnout area,which has certain practical engineering significance.This method is not only suitable for newly designed rails,but also for rail profile grinding in actual lines. |
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