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Numerical analysis of Hertzian and non-Hertzian wheel-rail contacts.

机译：赫兹和非赫兹轮轨接触的数值分析。

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摘要

Improved rail car designs which can provide faster, safer and more economical transportation, often require a significant amount of dynamic analysis and simulation. Of the many important processes that simultaneously occur during the rolling of wheels on rails, one of the most important is that of the contact mechanics at the wheel-rail interface. The forces which develop within the contact patch are ultimately responsible for coupling the dynamics of the rail car to the geometry of the rail. This work seeks to understand the mechanics of wheel-rail contacts and to define the governing parameters in a generalized format which can be used for dynamic rail car simulation. Emphasis is given to non-Hertzian contact geometries and the tribological implications of frictional work.;The mechanics of both Hertzian and non-Hertzian contacts were studied with the aid of a variety of computational tools. A detailed parametric analysis was performed for a 136RE X AAR1-B rail-wheel combination. Three different regimes of contact were identified (assuming unworn profiles) between the rail crown and gauge corner. Two were Hertzian and the other was non-Hertzian. Solution to the normal problem for each regime of contact was obtained over a wide range of wheel loads. Using the results of the normal problem, solutions to the tangential problem were obtained for each regime of contact for a wide range of creepages. This was accomplished for the non-Hertzian contact by using both a non-Hertzian algorithm as well as postulating the existence of an ellipticized non-Hertzian contact and treating it with classic Hertzian methods. This latter method showed that the non-Hertzian nature of wheel-rail contacts does not significantly alter the classic creep force - creepage behavior (for non-Hertzian contacts having a geometric distortion of ;Results of the parametric analysis also revealed a set of generalized surface equations capable of approximating both longitudinal and lateral creep force as a function of the creepages and patch aspect ratio. The form of these equations was found to be most accurately represented by the hyperbolic tangent function. Speed and accuracy tests of the approximating functions showed favorable results when compared to other codes that were based on complete creep force - creepage theories.;Generalized approximating equations were also obtained which accurately represented the behavior of global contact patch friction work. The distribution of local patch friction work was also obtained for both Hertzian and non-Hertzian contacts. Due to the asymmetry of traction and slip profiles for the non-Hertzian patch, a unique bi-modal patch friction work profile was obtained.
机译：可以提供更快，更安全和更经济的运输的改进的轨道车设计通常需要大量的动态分析和仿真。在轨道上的车轮滚动过程中同时发生的许多重要过程中，最重要的过程之一是轮轨界面处的接触力学。在接触贴片内产生的力最终负责将轨道车的动力学耦合到轨道的几何形状。这项工作旨在了解轮轨接触的力学原理，并以可用于动态轨道车辆仿真的通用格式定义控制参数。重点介绍了非赫兹接触的几何形状以及摩擦功的摩擦学意义。借助多种计算工具研究了赫兹接触和非赫兹接触的力学。对136RE X AAR1-B轨道轮组合进行了详细的参数分析。在钢轨胎冠和轨距角之间确定了三种不同的接触方式（假设未磨损的轮廓）。两个是赫兹族，另一个是非赫兹族。在广泛的车轮载荷范围内，可以获得每种接触方式的正常问题的解决方案。使用正常问题的结果，针对各种爬电距离的每种接触方式，均可得到切线问题的解。对于非赫兹接触，这是通过使用非赫兹算法以及假设存在椭圆化非赫兹接触并使用经典赫兹方法对其进行处理而实现的。后一种方法表明，轮轨接触件的非赫兹特性不会显着改变经典的蠕变力-蠕变行为（对于几何变形为的非赫兹触点，参数分析的结果还显示出一组广义表面能够将纵向和横向蠕变力都近似为蠕变和斑长宽比的函数的方程，这些方程的形式最精确地由双曲线正切函数表示，近似函数的速度和精度测试显示了良好的结果与其他基于完全蠕变力-蠕变理论的规范进行比较；还获得了广义逼近方程，可以精确地表示整体接触补丁摩擦功的行为；还获得了赫兹和非赫兹分布的局部补丁摩擦功的分布-赫兹接触，由于牵引力和滑移曲线的不对称性在非赫兹贴片中，获得了独特的双峰贴片摩擦工作曲线。

著录项

  • 作者

    Harder, Robert Fredrick.;

  • 作者单位

    Oregon Graduate Institute of Science and Technology.;

  • 授予单位 Oregon Graduate Institute of Science and Technology.;
  • 学科 Applied Mechanics.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 1995
  • 页码 230 p.
  • 总页数 230
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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