| Turnouts,as key components for turning and crossing tracks of locomotives and vehicles,have complex structures and numerous components,which are prone to wear during train operation.At the same time,they are one of the three weak links on the track.With the increase in the operating speed and mileage of high-speed railways in China,the safety and economic problems caused by turnout wear on high-speed railways are becoming increasingly serious.Therefore,the contour of the turnout has been optimized to reduce turnout wear,it is very important to improve the performance of trains in the process of crossing a turnout and extend the service life of the turnout.The outline of the turnout has been optimized and designed.Based on the research object of the curved switch rail in the switch area of the No.18 turnout on the passenger dedicated line,and based on the optimization design method of the switch profile characterized by the circular arc tangent point,the key section profile of the curved switch rail in the switch area is fitted using the circular arc profile theory,and based on the fitted profile,the simulated degradation algorithm is used as the optimization algorithm for optimization.By analyzing the wheel turnout contact geometric relationship before and after the optimization of the key section profile,conduct simulation verification and analysis on vehicle turnout coupling dynamics performance,contact finite element contact force between wheels and turnout,and wear prediction depth.The research results of this article are as follows:(1)Optimization of the curve and switch rail profile in the turnout switch area.According to the circular arc curve theory,the key section of the curved switch rail in the switch area is fitted,and a simulated annealing algorithm is used as the optimization algorithm.Based on the measured turnout profile data,the input values are set to the arc endpoint and radius of the design variables.The objective function is to reduce the difference between the predicted minimum wear and contact stress,and the constraint conditions of the profile optimization model are the wheel-rail gap and the geometric boundary of the key section profile of the turnout,The optimized profile satisfying the conditions is output through algorithm iteration.(2)A dynamic model of vehicle turnout system is established.Based on this model,the dynamic performance of the standard and optimized profiles of high-speed train CRH2 passing through the switch area is analyzed.After adopting the optimized profile,for safety,the maximum derailment coefficient decreases from 0.69 to 0.65,a decrease of 0.04 and 9.4%;The maximum wheel load reduction rate decreased from 0.198 to 0.177,a decrease of 0.219,or11.1%;For stability,the maximum lateral force of the wheel/rail decreases from 39.9KN to38.6KN,a decrease of 1.3KN,with a decrease of 3.3%.The maximum vertical force of the wheel/rail decreases from 87.2KN to 83.4KN,a decrease of 4.2KN,with a decrease of 4.8%;For comfort,the maximum lateral vibration acceleration of the vehicle body decreased from0.456 to 0.437,a decrease of 0.019 and a decrease of 3.6%;The optimized profile dynamic performance has been improved to a certain extent,thereby improving the safety,comfort,and stability of trains passing through the turnout switch area in reverse direction.(3)A wheel rail contact finite element model of the turnout switch area is established.Based on this model,the finite element analysis of the standard profile and optimized profile wheel rail contact between the standard LMA wheel tread and five key sections was conducted.After using the optimized profile,the maximum Von-Mises stress values of each key section of the standard LMA wheel and the turnout curved switch rail decreased by 5.6%,13.6%,14.9%,12%,and 11.7%,respectively,with an average decrease of 11.6%.Compared to the standard profile,the maximum contact stress of the optimized profile and the standard wheel LMA decreased by 9.1%,8.4%,11.4%,6.9%,and 11.7%,respectively,with an average decrease of9.5%.It is shown that the contact performance of the optimized profile is superior to that of the standard profile,which is more beneficial for reducing turnout wear and extending the service life of the turnout.(4)The wear simulation model of the curved switch rail in the turnout switch area is established.Based on this model,the wear depth of the standard profile and the optimized profile of five key sections was analyzed.Compared to the standard profile,the wear depth of each section decreased to varying degrees after using the optimized profile.The peak value was reached at the No.2 section with a top width of 20 mm of the curved switch rail.The total throughput before and after optimization was respectively 20 Mt,40 Mt,and 60 Mt,which decreased by 0.45,0.69,and 0.82,with a decrease of 37.5%,31%,and 24%,respectively,it is shown that the optimized profile can significantly reduce the wear between wheels and rails. |
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