Research On Damage Characterization And Function Evaluation Of Advanced Ceramics Ground Surface

At present, surface topography characterization methods of advanced ceramicsare similar to metal, mainly using roughness index. However, the surface topographyof them is significantly different even with the same Ra value. This different is causedby the phenomenon that advanced ceramics belong to hard and brittle materials andeasy to form damage such as breaks and cracks during processing. Besides, surfacetopography has an influence on service performance and fitting performance,especially on sealing, lubrication, fatigue and wear. Therefore, it is necessary to find amore suitable method to characterize advanced ceramics surface topography.The aim of this paper is to find a new characterization method which can be usedto complement the traditional roughness approach. The main contents include: extracts and evaluates the local characteristics of advanced ceramics ground surface usingthe wavelet method; chooses a suitable method to calculate profile dimension ofceramic ground surface by comparing various methods; describes the surfacetopography of advanced ceramics using the fractal method from the global perspective;develops a fractal model of wear based on fractal method and adhesion theory;propose the optimum fractal dimension in wear process; analyze the affect factors ofoptimum fractal dimension; studies sealing of profile, material ratio curve of theprofile and spectrum characteristics. Finally, a surface measurement and analysissystem which suit advanced ceramics is developed using matlab software.From theoretical analysis and the experiment, the following conclusions can bedrawn:(1) Using this wavelet analysis, the damage of advanced ceramic ground surfaceis extracted accurately. Evaluate the advanced ceramic ground surface damagequantitatively using the surface damage ratio and the average distance of surfacedamage.(2) Comparison various methods and verification using3D surface topography,the variation method is suitable for extracting fractal dimension of advanced ceramicsground surface. The precision of variation method is further studied. Based on theanalysis, we can draw a conclusion that the variation method is a reliable method for calculation of the fractal dimension for advanced ceramics.(3) The model of wear and seal is developed based on fractal method. The resultof advanced study show that the sealing effect is better when the fractal dimension islarger, wear rate is lowest when the fractal dimension is a certain value.(4) The fractal method can describe the complex of surface topography fromglobal perspective. The wavelet method can describe the local characterization ofsurface topography.The compose of wavelet method and fractal method can describesurface well.(5) The surface measurement and analysis system which suit advanced ceramicssurface is developed using matlab software.