激光切割表面三维形貌的分形特征

利用白光干涉仪测量激光切割碳素钢表面轮廓数据,应用分形几何学分析激光切割表面的三维形貌特征.采用盒计数法计算激光切割表面的三维分形维数.结果表明：不存在一个超越尺度范围普适的分形维数,只有当尺度r小于轮廓最大高度Ry,才表现出分形特征.对同一激光切割表面进行表征时,同尺度的Ra沿厚度方向变化波动较大,分形维数Db能够对整体表面形貌的复杂程度有着较稳定的表征.分析激光切割表面的三维形貌特征,分形维数表征激光切割表面微观结构的复杂程度,表面粗糙度可对激光切割表面轮廓高度特性进行辅助评价.

Fractal characteristics of laser cutting three-dimensional surface topography

This paper discusses the measurement of the Contour Data of laser cutting Carbon steel surface using the white light interferometer,the study of the surface topography characteristics of laser cutting based on the fractal geometry,and the calculation of the three-dimensional fractal dimension of the laser cutting surface using box-counting method.The results show the absence of pervasive fractal dimension beyond a scale range and the presence of the fractal characteristics on the laser cutting surface,only when the scale r is less than maximum height of the contours Ry.Characterization of the same laser cutting surface is accompanied by a great fluctuation in the same scale Ra along the thickness direction and a stable characterization of the complexity of the whole surface topography by the fractal dimension Db.The analysis of the characteristics of the laser cutting three-dimensional surface is obtained by characterizing the micro-structured complexity of laser cutting surface using the fractal dimension,which is aided by the roughness to evaluate the contour height characteristics of laser cutting surface.