The Characteristic Analysis Of Joint Surface Contact Based On Fractal Theory

With the needs of miniaturization and high precision of machine tool research, the contact behavior of the machine tool guide joint surface plays a more important role on the whole machine tool. Traditional mechanics focuses on analyzing and studying with surface contact behavior in the context of large scale, while ignoring the parameter information of small-scale context. In the microcosmic state, engineering actual contact surface actually is lots of micro convex-body’s contact between each other. The contact behavior is an important research issue in modern tribology. At present the analysis on surface contact problems are based on the statistical methods or the measured data, the former does not have the time variable of engineering practice, while the workload of the latter is too heavy.This paper first introduced the analysis of the characterization method of rough surface, the numerical simulation method based on the fractal theory and the measured surface topography data to characterize the reverse modeling method are used after the comparative study.In this paper, with the help of LI-3 type profile meter we measured the surface 3D shape of different roughness (Ra=3.2、Ra=1.6、Ra=0.8) casting process experimental specimens, and obtained the relevant profile data. According to relative position of data interception, we got the 2D contour curve of the position. The Analysis of the intercepted data taking advantage of the structure function method verified that the engineering practice surface has fractal characteristics and obtained the fractal parameters. We then established the corresponding fractal surface model by using the software of Matlab, according to the calculated fractal parameters and the W-M function. After the morphology data of two kinds of surface morphology of the measured and fractal analog were converted into the needed format, they were imported into the Solidworks software to establish the corresponding surface entity model, then with the help of finite element analysis software ANSYS, the finite element contact model was established, finally we carried on the contact state simulation analysis based on the two kinds of model under different roughness. After a comparison of the simulation results, we could find the change rules of parameters between the two types of models under certain conditions, and then obtain the surface fractal simulation which may replace the actual surface used "in advance" analysis.This paper also made contact analysis on the measured rough surface of samples with different length but the same roughness, sketched 5 kinds of contact area, maximum deflection and load diagrams of different sampling length corresponding to the measured surface topography model. This research will serve as a good verification and reference for future study of establishing a unified multi-scale model only related to a certain parameter.