碳纤维复合材料表面形貌测量采样条件研究

Sample Conditions of Measurement of Carbon Fibre Composite Surface Topography

采样条件的确定对表面微观几何形状误差评定的准确性有重要影响。针对现实中用户依据自身经验选择采样条件的不确定性,提出了一种能够客观判定最佳采样条件的方法。基于二维功率频谱分析,考虑奈奎斯特采样定理与混叠效应,提出一个归一近似因子来确定合适采样条件。经实验验证其适用于碳纤维复合材料表面形貌测量,研究证明用较大采样间距多次测量加工后工件的表面形貌,取粗糙度值的平均值或St、Sp和Sv取最大值来评定其表面质量更合理。

Determination of sample conditions is of great influence on the surface assessment of microscopic geometry error. Aimed at the uncertainty in selecting sample conditions for the users depending only on their own experience, one method that can determine appropriate sample conditions objectively was developed. Based on 2D spectral analysis and considering the Nyquist sampling theorem and aliasing effect, a normalized proximity factor was proposed to determine proper sample conditions. Experiments validate it applies to the measurement of surface of carbon fibre composites. Results indicate that it is more reasonable to measure the surface of machined workpieees several times with larger sample space and select the mean or maximal values of roughness.