Based On Fractal Theory Study On Micro-contact Characteristics Of Joint Surface Of Machine Guide

Dynamic characteristics of guide joint surface has an important influence on dynamic characteristics of machine, while the micro-scale dynamic characteristics of guide joint surface is the foundation and key of the complex mechanical systems designing and the dynamic designing and optimizational designing for micro-mechanical systems, so the study on micro-contact characteristics between real rough surfaces is very needed. Current characterization of rough surfaces often using traditional quantitative description method based on statistics, but Such characterizations does not have objective and uniqueness, so there are many inconveniences in practical use. Characterizing rough surfaces using fractal theory, the characterization results contain all the information on multiple scales. It is in favour of research on contact of rough surfaces.Proposed in this paper are two ways to modeling the rough surface:based on measured data on real rough surface and simulating by fractal theory, and using the Geomagic studio reverse modeling software to optimize the modeling process, finally the two types of rough surfaces model are used to analyzed in contact simulation by finite element numerical simulation, and discussing the two types of rough surface contact model during contact analysis of similarities and differences.Using an atomic force microscope(AFM) measuring roughness class of three experimental specimen in the grinding(Ra=3.2、Ra=1.6、Ra=0.8) to get the real three dimensional rough surface topography data, and proves the specimen surfaces have fractal characteristics with structure function method. Generating the rough surfaces according to the corresponding fractal parameters of the measurement data with the W-M two anisotropic fractal simulation and MATLAB programming.Respectively, using the measured data and the fractal simulation data in turn in reverse modeling software Geomagic studio,3d modeling software Pro/E and finite element analysis software ANSYS in surface modeling, solid modeling and rough surface contact finite element simulation analysis. Based on two types of contact model of dimensionless simulation results and error analysis, verifying that the fractal simulation method can effectively characterize the microstructure of the engineering actual rough surface and simulation of rough surfaces through this method under certain conditions are met can be used instead of engineering rough surface contact analysis.Results of this research have a good reference value for building a multiscale contact model between rough surfaces and controling topography of rough surface to improve contact characteristics.