基于分形理论的气缸套磨损表面特征形貌表征

摘要

Based on the theory of fractal dimension and multi-fractal spectrum, the friction wear testing samples of chromium cylinder liner and PVD (physical vapour deposition) piston-ring mating partner under different operating conditions were studied. The two dimensional grey-scale map of wear surface was acquired by using the three dimensional focusing laser scanning microscope and was changed into the monochrome bianry image. The fractal dimension was calculated with the box-dimensional method, the spectrum width of wear surface was estimated with the multi-fractal spectrum, and then the surface topography and roughness of cylinder liner were quantitatively characterized. The results show that the liner wear surface has the obvious fractal characteristics and is one-dimensional. It is obvious that the rougher surface, the less fractal dimension and the larger fractal spectrum width.%基于分形维数和多重分形谱理论,以不同工况下镀铬气缸套 PVD活塞环摩擦磨损试验试样为对象,通过三维共聚焦激光扫描显微镜获取磨损表面的二维灰度图像,并将其转化成黑白二值图像,采用盒维数法测算缸套磨损表面的分形维数,运用多重分形谱测算谱宽度,定量表征气缸套磨损表面的形貌特征和表面的高度均一性.结果表明,气缸套磨损表面具有明显的分形特征,且为一重分形.表面越粗糙,分形维数越小,分形谱宽度值越大.