This paper aims to study the relationship between normal contact stiffness and contact load. It purpose a new calculation model of the normal contact stiffness of joint surfaces by considering the elastic–plastic critical deformation change of asperities contact.,The paper described the surface topography of joint surfaces based on fractal geometry, and fractal parameters and of fractal function derived from measurement data. According to the plastic–elastic contact theory, the contact deformation characteristic of asperities was analyzed; the critical deformation estimation model was presented, which expressed critical deformation as the function of fractal parameters and contact deformation; the contact stiffness calculation model of single asperity was brought forward by considering critical deformation change.,The paper combined the surface topography description function, analyzed the asperity contact states by considering the critical deformation change, and calculated normal contact stiffness based on fractal theory and contact deformation analysis. The comparison between theoretical contact stiffness and experimental data indicated that the theoretical normal contact stiffness agreed with the experimental data, and the estimation model for normal contact stiffness was appropriate.,Owing to the possibility of plastic deformation during the loading process, the experimental curve between the contact stiffness and the contact load is nonlinear, resulting in an error between the experimental results and the theoretical calculation results.,The paper established the relationship between critical deformation and fractal surface topography by constructing asperity distribution function. The paper proposed a new normal contact stiffness calculation model of joint surfaces by considering the variation of critical deformation in contact process.

中文翻译：

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考虑临界变形变化的关节面法向接触刚度估计

本文旨在研究法向接触刚度与接触载荷之间的关系。考虑凹凸体接触的弹塑性临界变形变化,建立了关节面法向接触刚度的新计算模型。,本文描述了基于分形几何的关节面表面形貌,以及分形参数和导出的分形函数从测量数据。根据塑性-弹性接触理论，分析了凹凸不平的接触变形特性；提出了临界变形估计模型，将临界变形表示为分形参数和接触变形的函数；考虑临界变形变化，提出了单一粗糙面的接触刚度计算模型。结合表面形貌描述函数，考虑临界变形变化分析凹凸接触状态，基于分形理论和接触变形分析计算法向接触刚度。理论接触刚度与实验数据对比表明，理论法向接触刚度与实验数据吻合，法向接触刚度估计模型合适。接触刚度和接触载荷是非线性的，导致实验结果与理论计算结果存在误差。论文通过构造粗糙度分布函数，建立了临界变形与分形表面形貌之间的关系。考虑接触过程中临界变形的变化，提出了一种新的关节面法向接触刚度计算模型。