Abstract

The application of oil-bearing joint that is widely used in various mechanical equipment can effectively improve the dynamic characteristics of integrated machineries. A fractal contact model of oil-bearing joint considering the effect of asperity interaction is proposed in this article. The equivalent stiffness and damping of oil-bearing joint are divided into a solid contact portion and a liquid contact portion. On the basis of elastic mechanics and fractal theory, the deformation of a single asperity of solid contact part is deduced. The stiffness and damping model considering the asperity interaction are obtained from the relationship between normal load and deformation. The stiffness and damping expression of the liquid contact part are also deduced based on the generalized Reynolds equation. It is concluded that the equivalent stiffness increases with the increase of the fractal dimension and the decrease of the fractal roughness parameter. At the same time, increasing the hydrodynamic viscosity can demonstrably improve the contact stiffness. Experiment shows that the proposed model is more in line with the actual load-stiffness relationship. The model considers the factor of asperity interaction and provides a theoretical basis for predicting the dynamic characteristics of oil-bearing joint.

• Highlights

• An accurate theoretical model of the dynamic characteristics for the oil-bearing joint surface was established.

• Identification of the dynamic properties of the oil-bearing joint surface using frequency response functions.

• The factors influencing the stiffness of solid portion and liquid portion were studied, respectively.

摘要

广泛应用于各种机械设备的含油接头的应用，可以有效改善综合机械的动态特性。本文提出了一种考虑粗糙相互作用影响的含油接头分形接触模型。含油接头的等效刚度和阻尼分为固体接触部分和液体接触部分。在弹性力学和分形理论的基础上，推导了固体接触部分单个凹凸不平的变形。考虑了粗糙度相互作用的刚度和阻尼模型是从法向载荷和变形之间的关系得到的。液体接触部分的刚度和阻尼表达式也基于广义雷诺方程推导出来。得出的结论是等效刚度随着分形维数的增加和分形粗糙度参数的减小而增加。同时，增加流体动力粘度可以明显提高接触刚度。实验表明，所提出的模型更符合实际的荷载-刚度关系。该模型考虑了粗糙相互作用的因素，为含油接头的动态特性预测提供了理论依据。

• 强调

• 建立了含油接合面动态特性的精确理论模型。

• 使用频率响应函数识别含油接合面的动态特性。

• 分别研究了影响固体部分和液体部分刚度的因素。