考虑廓形曲率阶跃特征的钢轨砂带打磨静态接触行为研究

Research on Static Contact Behavior for Rail Grinding by Abrasive Belt Considering the Curvature Step Characteristics of Rail Profile Curve

钢轨打磨接触问题研究目前主要集中在将钢轨轮廓简化为圆柱面层面,而忽视了钢轨廓形曲线由多段圆弧组成这个事实。为此,考虑钢轨廓形曲线的曲率阶跃特征,基于赫兹接触理论,建立钢轨砂带打磨静态接触理论模型,确定打磨角度与打磨接触点间的数学关系,对钢轨进行离散化切片处理,获得接触区域内应力分布和接触斑形态。对五个不同打磨接触位置分别进行数值计算和接触实验,发现理论结果和实验结果呈现较高程度的吻合,在接触区域不存在曲率阶跃的情况下接触斑呈现较为规则的椭圆形态,在接触区域存在曲率阶跃的情况下接触斑在分界线两侧的形态差别较大,并且随着法向压力的增大差异更加明显,验证了所建立理论接触模型的正确性与有效性。

At present,the research on the contact problem of rail grinding mainly focuses on simplifying the rail profile to the cylindrical surface level,while ignoring the fact that the rail profile curve is composed of multiple arcs.For this purpose,considering the curvature step characteristics of rail profile curve,based on the Hertz contact theory,a static contact theory model of rail grinding by abrasive belt is established.Through deducing the mathematical relationship between grinding angle and grinding contact point,and discretizing the rail profile into many slices,the stress distribution and contact spot morphology within the contact area are obtained.The numerical calculation and contact experiment for the five different grinding contact positions are implemented.The theoretical results are found to be in good agreement with the experimental results.When there is no curvature step phenomenon in the contact region,the contact spot shows the regular oval shape.On the contrary,the morphology of contact spot on both sides of the dividing line is quite different,and the difference is more obvious with the increase of normal pressure.The correctness and validity of the theoretical contact model are verified.