大量机械加工表面存在各向异性特征,而现有分形算法生成的复杂表面大多是各向同性的.为此,在现有分形各向异性表面建模方法的基础上,对采用频域伸缩法生成的各向异性分形表面的形貌特征进行了分析,通过在频域中引入角度参量的方法对算法进行改进,使生成的表面纹理方向可控.实验证明:通过该方法获取的表面形貌具有明显的各向异性特征;伸缩比可以控制表面轮廓分形维数的变化;通过控制表面轮廓的频率分量可以对表面进行滤波,在此基础上可对表面进行多尺度分析观察.文中最后结合微犁切沟槽表面形貌具有各向异性特征的特点,采用TalysurfCLI1000表面轮廓仪测量微沟槽工件形貌,并分析其表面分形特征,在此基础上对AutoCAD软件进行二次开发并得到了微沟槽几何模型.
Most artificial surfaces generated by the existing fractal surface generation algorithms are isotropic, which are different from most anisotropic mechanical surfaces. In order to solve this problem, the existing anisotropic surface generation methods are reviewed and the morphology of the anisotropic fractal surface generated by the method of frequency domain stretching is analyzed. Then, the method is improved by introducing an angle parameter in the frequency domain, which makes the direction of anisotropy controllable. Experimental results indicate that the surface obtained by the improved method is obviously anisotropic, that the fractal dimension of the extracted profile depends on the stretch radio, and that the surface filtering can be implemented by controlling the frequency component of the extracted profile, which makes the multi-scale resolution possible. Moreover, according to the anisotropy of the ploughed micro-groove's surface, the profiles are scanned by a surface coarseness profiling instrument Talysurf CLI 1000, and the fractal feature of the micro-groove surface is analyzed, based on which a geometrical model of ploughed micro-groove is established via the secondary development of AutoCAD.