基于双树复小波变换的SiCP/Al复合材料加工表面质量评价

摘要

The machining surface of SiCP/Al composites contains of lots of bumps,potholes and defects,leading to the confusion of roughness and defect information and unreasonable evaluation of the machining surface.In order to extracting the surface roughness and evaluating of the machining surface of SiCP/Al composites reasonably,a filtering method based on dual tree complex wavelet transform(DT-CWT)was put forward in this paper.The least squares method,Gaussian filtering method and the filtering method based on DT-CWT were adopted to extract the information of surface roughness and evaluated from two aspects including stability and degree of influence by defects.The results show that filtering method based on DT-CWT has high stability and can distinguish surface roughness from defect information more effectively.Therefore,it is more suitable for the extract of the surface roughness of SiCP/Al composites.According to comparison between the machining surface of SiCP/Al whose Al-matrix includes of 2 0 2 4 and 6 0 6 3 aluminum alloy by the filtering method base on DT-CWT,it is found that the quality of 2 0 2 4 aluminum matrix composite surface is better than that of 6 0 6 3 aluminum composite.%SiCP/Al复合材料切削加工表面存在大量的凸起、凹坑和沟槽等缺陷,获取表面粗糙度信息时易将缺陷信息计入到粗糙度中,从而影响加工表面质量的合理评价.为提取加工表面粗糙度信息,合理评价 SiCP/Al 复合材料加工表面质量,提出一种基于双树复小波变换(DT-CWT)的滤波方法.采用最小二乘法、高斯滤波法和 DT-CWT变换的滤波方法对已加工表面进行粗糙度提取,从稳定性及受缺陷影响程度两个方面对三种方法的粗糙度信息提取效果进行对比.结果表明:基于DT-CWT的滤波方法具有较高的稳定性,并能够更有效区分表面粗糙度及缺陷信息,更适于 SiCP/Al复合材料加工表面粗糙度信息提取.应用基于DT-CWT的滤波方法,对不同 Al 基体的 SiCP/Al复合材料切削加工表面质量评价的结果表明:SiCP/2024Al 复合材料表面质量明显优于 SiCP/6063Al复合材料.