It is widely recognized that the accuracy of explicit finite element simulations is sensitive to the choice of interface parameters (i.e. contact stiffness/damping, mesh generation, etc.) and time step sizes. Yet, the effect of these interface parameters on the explicit finite element based solutions of wheel–rail interaction has not been discussed sufficiently in literature. In this paper, the relation between interface parameters and the accuracy of contact solutions is studied. It shows that the wrong choice of these parameters, such as too high/low contact stiffness, coarse mesh, or wrong combination of them, can negatively affect the solution of wheel–rail interactions which manifest in the amplification of contact forces and/or inaccurate contact responses (here called “contact instability”). The phenomena of “contact (in)stabilities” are studied using an explicit finite element model of a wheel rolling over a rail. The accuracy of contact solutions is assessed by analyzing the area of contact patches and the distribution of normal pressure. Also, the guidelines for selections of optimum interface parameters, which guarantee the contact stability and therefore provide an accurate solution, are proposed. The effectiveness of the selected interface parameters is demonstrated through a series of simulations. The results of these simulations are presented and discussed.

中文翻译：

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显式有限元分析中轮轨界面参数对接触稳定性的影响

人们普遍认为，显式有限元模拟的精度对界面参数（即接触刚度/阻尼、网格生成等）和时间步长的选择很敏感。然而，这些界面参数对基于显式有限元的轮轨相互作用解决方案的影响尚未在文献中得到充分讨论。本文研究了界面参数与接触解精度之间的关系。它表明，这些参数的错误选择，例如过高/过低的接触刚度、粗网格或它们的错误组合，会对轮轨相互作用的求解产生负面影响，这表现为接触力的放大和/或不准确接触反应（此处称为“接触不稳定”）。使用车轮在轨道上滚动的显式有限元模型研究“接触稳定性”现象。通过分析接触斑块的面积和法向压力的分布来评估接触解决方案的准确性。此外，还提出了选择最佳界面参数的指南，以保证接触稳定性，从而提供准确的解决方案。通过一系列模拟证明了所选接口参数的有效性。介绍并讨论了这些模拟的结果。