【作者】 王志伟；

【导师】 王良璧； 李建锋；

【作者基本信息】 兰州交通大学 ， 机械工程（专业学位）， 2019， 硕士

【摘要】 随着我国经济的高速发展,铁路运输系统也迅猛发展。高速化和重载化是铁路发展的重要趋势,在这种发展情况下,轮轨之间的接触机理变得越发复杂,轮轨之间的接触工况日益恶化。轮轨具有复杂的几何形状并且轮轨之间的接触问题为高度的非线性行为,此前对于轮轨之间的接触问题多基于Hertz接触理论,但是由于Hertz接触理论的局限性,并不能真正的揭示轮轨之间的接触状况。随着大型有限元分析的发展,利用有限元分析软件计算轮轨之间的接触应力能够反映实际情况下的轮轨接触应力,为轮轨问题的研究提供可靠的数值依据。本文根据轮轨之间的接触关系,结合轮轨摩擦学、轮轨接触理论、传热学、弹性力学等理论,利用ANSYS建立了三维轮轨接触有限元模型。车轮和钢轨采用了弹性体假设,选取了不同的轮对轴重载荷,模拟了轮轨在静载状态以及纯滚动工况下轮轨接触斑的形状、面积、接触压力及等效应力变化情况,并对纯滚动工况下摩擦热对轮轨接触斑的形状、面积、接触压力及等效应力的影响做了分析。得出了如下结论:(1)在静载状态下,随着轮对轴重的增大,轮轨接触应力也随之增大,轮轨的接触压力大于Hertz理论计算值。轮轨接触斑的形状大体上为椭圆形,但是由于轮轨型面的影响,在椭圆接触斑附近产生了较小的接触区域。接触斑的面积随着轴重的增加呈线性增加。车轮和钢轨的等效应力呈不规则的环形分布,最大等效应力均出现在接触表面2 mm左右的深度,随着轴重的增加,车轮和钢轨的等效应力也随之增加,增加的幅度相似,车轮和钢轨的最大等效应力值相近。(2)在纯滚动工况下,随着轮对轴重的增大,轮轨接触斑的面积、形状以及车轮和钢轨上的等效应力分布情况与静载条件下类似,接触压力与静载条件下相比略有增大,增大的幅度较小。(3)在摩擦热的作用下,轮对在纯滚动时,轮轨接触斑上的接触压力较无摩擦热作用下相应的减小,最大差值为1.14%,减小的幅度较小。接触斑的面积明显增加,最大增幅为7%。接触斑的形状与无摩擦热影响时相似。(4)在摩擦热的作用下,车轮和钢轨上的等效应力变化较为明显,等效应力的作用区域较无摩擦热时明显变大,影响深度也增加。随着轴重的增加,车轮和钢轨的最大等效应力增大,小于无摩擦热作用时轮轨的等效应力。更多还原

【Abstract】 With the rapid development of China’s economy,the railway transportation system has also been developed rapidly.High-speed and heavy-loading are important trends in the development of railways.Under this development,the contact mechanism between wheel and rail becomes more and more complicated,and the contact conditions between wheel and rail are deteriorating.The wheel-rail has complex geometry and the contact problem between the wheel and rail is a highly nonlinear behavior.Previously,the contact problem between the wheel and the rail was based on the Hertz contact theory,but due to the limitations of the Hertz contact theory,it cannot be truely reveal the contact between the wheel and rail.With the development of large-scale finite element analysis,the use of finite element analysis software to calculate the contact stress between wheel and rail can obtain more reliable results of the wheel-rail contact stress under actual conditions,and can provide a reliable method for the study of wheel-rail problems.According to the contact relationship between wheel and rail,combined with the theory of wheel-rail tribology,wheel-rail contact theory,heat transfer,elastic mechanics,etc.,the three-dimensional wheel-rail contact finite element model is established using ANSYS.The elastic assumption is made for the contact of wheel and rail,and different wheel-to-shaft heavy loads are selected to simulate the shape,area,contact pressure and equivalent stress of the wheel-rail contact spot under the static load condition and pure rolling condition.And the influence of frictional heat on the shape,area,contact pressure and equivalent stress of wheel-rail contact spots under pure rolling conditions was analyzed.The following conclusions were drawn:(1)Under the static load condition,as the axle weight increases,the wheel-rail contact stress also increases,and the contact pressure of the wheel-rail is greater than the value calculated by Hertz theory.The shape of the wheel-rail contact spot is generally elliptical,but due to the influence of the wheel-rail profile,a smaller contact area is created near the elliptical contact spot.The area of the contact patch increases linearly with increasing axial weight.The equivalent stress of the wheel and the rail is irregularly distributed,and the maximum equivalent stress appears at a depth of about 2 mm on the contact surface.As the axle weight increases,the equivalent stress of the wheel and the rail increases,and the magnitude of the increase increases.Similarly,the maximum equivalent stress values of the wheel and rail are similar.(2)Under pure rolling conditions,as the wheel axle weight increases,the area and shape of the wheel-rail contact spot and the equivalent stress distribution on the wheel and rail aresimilar to those under static load conditions.Contact pressure at static state compared with that at the rolling condition,it increases,but the increase is small.(3)Under the action of frictional heat,when the wheel pair is purely rolling,the contact pressure on the wheel-rail contact spot is correspondingly reduced compared to that under the no action of frictional heat,and the maximum difference is 1.14%,and the reduction is small.The area of contact spots increased significantly,with a maximum increase of 7%.The shape of the contact spot is similar to that under the no action of the friction heat.(4)Under the action of frictional heat,the equivalent stress changes on the wheel and the rail are more obvious.The effective stress area is obviously larger than that without considering friction heat,and the influence depth is also increased.As the axle weight increases,the maximum equivalent stress increases,and is less than the equivalent stress of the wheel rail without friction heat acts.更多还原