预防非工作边表面裂纹的直尖轨倒圆弧半径取值研究

针对高速道岔直尖轨非工作边表面出现纵向裂纹的问题,通过建立车辆道岔多体动力学模型和三维弹塑性轮轨接触有限元模型,分析倒圆弧半径对直尖轨等效应力及其作用位置的影响。结果表明:尖轨顶宽30mm到顶宽40mm断面间易发生非工作边表面裂纹,其中顶宽35mm断面的受力状态最为不利;倒圆弧半径取值越大,对尖轨降低值的影响越大,为降低对车辆轨道动力性能的影响,在相同条件下,应尽可能选择较小半径的倒圆弧;直尖轨倒圆弧能够有效降低内部的等效应力,并能增大应力作用位置到非工作边的距离;综合考虑直尖轨降低值和受力状态,倒圆弧半径取3mm时优于其他半径取值。

Study on Transition Radius of Straight Switch Rail to Prevent Surface Crack on Non-working Side

In view of the problem of the longitudinal surface crack on the non-working side of straight switch rail of high-speed railway turnout,the vehicle-turnout multi-body dynamic model and three-dimensional elastic-plastic model of wheel-rail contact were established to analyze the effect of transition radius on equivalent stress and its position of straight switch rail.The results show that surface cracks of non-working side are likely to occur between section with switch rail head width from 30 mm to 40 mm,where the stressing state of the section with rail head width of 35 mm is the worst.The greater the value of transition radius,the greater the impact on the height reduction of the switch rail.In order to reduce the impact on dynamic characteristics of vehicle-rail system,a smaller transition radius should be considered as far as possible under the same conditions.The transition arc can effectively reduce the equivalent stress of the switch rail,and increase the distance from stress working position to non-working side.The radius of 3 mm of transition arc is superior to other radii considering the height reduction and stressing state of the switch rail.