地铁道岔轨顶坡对尖轨磨耗的影响

Effect of rail top slope on subway switch rail wear

针对地铁道岔磨耗严重及使用寿命短等问题,利用有限元方法建立道岔区三维弹塑性轮轨接触计算模型,通过计算尖轨接触应力、接触斑面积及内部应力等,分析轨顶坡对尖轨磨耗的影响。模型中车轮型面采用实测磨耗状态LM型车轮型面。研究结果表明:设置轨顶坡时,尖轨接触应力及内部应力均比不设置轨顶坡的小;以尖轨顶宽35.5 mm断面为例,当轨顶坡从1/40增大到1/20时,其接触应力最大值从904.267 MPa减小至686.266 MPa,Von Mises应力最大值从552.123 MPa降低至493.755 MPa,状态由塑性变形转变为弹性变形,有利于减小尖轨磨耗;增大尖轨断面顶面宽度可以提高其受力状态,延长道岔使用寿命;综合考虑尖轨受力状态,1/20轨顶坡优于其他轨顶坡。

In view of existing states of subway switch’s serious wear and short service life, a three-dimensional elastic-plastic model of wheel-rail contact in turnout zone was established by the finite element method to analyze the effect of rail top slope on switch rail wear by calculating contact stresses, contact plaque areas and internal stresses of switch rail. In the model, the measured wear profile of LM type was adopted for the wheel profile. The results show that when the rail top slope is set, the stresses and internal stresses of switch rail are small. Taking the section as an example whose top width size is 35.5 mm, when the rail top slope increases from 1/40 to 1/20, the maximum contact stress decreases from 904.267 MPa to 686.266 MPa, and the maximum Von Mises stress decreases from 552.123 MPa to 493.755 MPa, whose status converts from the plastic deformation stage to the elastic deformation stage, and this will cause the decrease of the wear. The increase of switch rail’s top width can improve the stress state and increase service life, and the rail top slope 1/20 is superior to others on comprehensive consideration of the switch rail’s stress state.