关联表面分形特性的润滑模型

在分配有面粗糙度与材料表面分形特性关系的基础上，将分形特性引入润滑方程，提出了关联表面分形特性的润滑模型，并分析了润滑模型中压力流量因子和剪切流量因子与表面分形维数之间关系。计算结果表明：在相同分形维数（D）下，随着微突体纵横比v的增大，压力流量因子和剪切流量因子相应增大，且其随分形维数D的变化同随油膜粗糙度比H的变化相比呈现出更强的不规则特性，出现局部最大和最小值，并且分辨率较高。

Lubrication Equation Involving Surface Fractal Characteristics

The lubrication equations involving surface fractal characteristics have been established by introducing surface fractal dimension D in the conventional lubrication equations, based on an analysis of the relationship between the surface roughness and the fractal characteristics of the material. Thus the variations of the pressure flow factor and shear flow factor determined the present equations with the surface fractal dimension D are theoretically investigated and compared with that based on the conventional lubrication equations. The disadvantages of the conventional lubrication equations describing the pressure flow factor and the shear flow factor are analyzed. The surface fractal parameters of SAE52100 steel were measured with a Talor 6 profilemeter. By analyzing the relationship between the surface roughness and the fractal characteristics, the obtained fractal dimensions are introduced into the expressions of the pressure flow factor and the shear flow factor. Thus, the lubrication equations involving surface fractal characteristics are obtained. In the process of analysis of the relationship between the above factors and D, for simplification, one relatively moving surface is assumed to be absolute flat and the oil film thickness is assumed to be 1 mm. The calculation results reveal that at a fixed fractal dimension D, both the pressure flow factor and shear flow factor increase with increasing length to width ratio of a representative asperity. They experience more irregular and significant variation and show local maximum and minimum values of higher resolution with increasing D, as compared with the variations with oil film thickness to roughness ratio. The present results may be referenced to reasonably selecting of lubricated surfaces.