A computational analysis of the application of skewness and kurtosis to corrugated and abraded surfaces

In this work, we describe the results of our investigation into the relevance of skewness and kurtosis as measures of surface roughness. Two types of surfaces are computationally generated: abraded surfaces consisting of surface scratches, and corrugated surfaces consisting of hemispherical features. It was found that abraded surfaces could be well described by the skewness and kurtosis, which can both be specified by the degree of coverage by the features on a surface. These two parameters showed a large variation over the range of surfaces sampled. The root mean squared (RMS) slope and surface area ratio did not change significantly by comparison, and the RMS roughness changed significantly only for surfaces with a large variation of scratch depths. A monotonic relationship was found to exist between skewness and kurtosis for abraded surfaces composed mainly of smaller scratches. For corrugated surfaces, the skewness and kurtosis were nearly constant for surfaces with RMS roughness values that differed significantly. The RMS roughness, RMS slope, and surface area ratio changed significantly by comparison. No monotonic relationship was found between the skewness and kurtosis for corrugated surfaces. This indicates that corrugated surfaces are best described by the RMS roughness, RMS slope, and surface area ratio rather than the skewness and kurtosis.