Multiscale Characterizations of Surface Anisotropies
Anisotropy can influence surface function and can be an indication of processing. These influences and indications include friction, wetting, and microwear. This article studies two methods for multiscale quantification and visualization of anisotropy. One uses multiscale curvature tensor analysis a...
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doaj-65e65c3f58cf48e693450dc01baa60a72020-11-25T03:07:14ZengMDPI AGMaterials1996-19442020-07-01133028302810.3390/ma13133028Multiscale Characterizations of Surface AnisotropiesTomasz Bartkowiak0Johan Berglund1Christopher A. Brown2Institute of Mechanical Technology, Poznan University of Technology, 60-965 Poznań, PolandDepartment of Manufacturing, RISE Research Institutes of Sweden, SE-43153 Mölndal, SwedenSurface Metrology Lab, Worcester Polytechnic Institute, Worcester, MA 01609, USAAnisotropy can influence surface function and can be an indication of processing. These influences and indications include friction, wetting, and microwear. This article studies two methods for multiscale quantification and visualization of anisotropy. One uses multiscale curvature tensor analysis and shows anisotropy in horizontal coordinates i.e., topocentric. The other uses multiple bandpass filters (also known as sliding bandpass filters) applied prior to calculating anisotropy parameters, texture aspect ratios (Str) and texture directions (Std), showing anisotropy in horizontal directions only. Topographies were studied on two milled steel surfaces, one convex with an evident large scale, cylindrical form anisotropy, the other nominally flat with smaller scale anisotropies; a µEDMed surface, an example of an isotropic surface; and an additively manufactured surface with pillar-like features. Curvature tensors contain the two principal curvatures, i.e., maximum and minimum curvatures, which are orthogonal, and their directions, at each location. Principal directions are plotted for each calculated location on each surface, at each scale considered. Histograms in horizontal coordinates show altitude and azimuth angles of principal curvatures, elucidating dominant texture directions at each scale. Str and Std do not show vertical components, i.e., altitudes, of anisotropy. Changes of anisotropy with scale categorically failed to be detected by traditional characterization methods used conventionally. These multiscale methods show clearly in several representations that anisotropy changes with scale on actual surface measurements with markedly different anisotropies.https://www.mdpi.com/1996-1944/13/13/3028surface textureanisotropymultiscale |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Tomasz Bartkowiak Johan Berglund Christopher A. Brown |
spellingShingle |
Tomasz Bartkowiak Johan Berglund Christopher A. Brown Multiscale Characterizations of Surface Anisotropies Materials surface texture anisotropy multiscale |
author_facet |
Tomasz Bartkowiak Johan Berglund Christopher A. Brown |
author_sort |
Tomasz Bartkowiak |
title |
Multiscale Characterizations of Surface Anisotropies |
title_short |
Multiscale Characterizations of Surface Anisotropies |
title_full |
Multiscale Characterizations of Surface Anisotropies |
title_fullStr |
Multiscale Characterizations of Surface Anisotropies |
title_full_unstemmed |
Multiscale Characterizations of Surface Anisotropies |
title_sort |
multiscale characterizations of surface anisotropies |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2020-07-01 |
description |
Anisotropy can influence surface function and can be an indication of processing. These influences and indications include friction, wetting, and microwear. This article studies two methods for multiscale quantification and visualization of anisotropy. One uses multiscale curvature tensor analysis and shows anisotropy in horizontal coordinates i.e., topocentric. The other uses multiple bandpass filters (also known as sliding bandpass filters) applied prior to calculating anisotropy parameters, texture aspect ratios (Str) and texture directions (Std), showing anisotropy in horizontal directions only. Topographies were studied on two milled steel surfaces, one convex with an evident large scale, cylindrical form anisotropy, the other nominally flat with smaller scale anisotropies; a µEDMed surface, an example of an isotropic surface; and an additively manufactured surface with pillar-like features. Curvature tensors contain the two principal curvatures, i.e., maximum and minimum curvatures, which are orthogonal, and their directions, at each location. Principal directions are plotted for each calculated location on each surface, at each scale considered. Histograms in horizontal coordinates show altitude and azimuth angles of principal curvatures, elucidating dominant texture directions at each scale. Str and Std do not show vertical components, i.e., altitudes, of anisotropy. Changes of anisotropy with scale categorically failed to be detected by traditional characterization methods used conventionally. These multiscale methods show clearly in several representations that anisotropy changes with scale on actual surface measurements with markedly different anisotropies. |
topic |
surface texture anisotropy multiscale |
url |
https://www.mdpi.com/1996-1944/13/13/3028 |
work_keys_str_mv |
AT tomaszbartkowiak multiscalecharacterizationsofsurfaceanisotropies AT johanberglund multiscalecharacterizationsofsurfaceanisotropies AT christopherabrown multiscalecharacterizationsofsurfaceanisotropies |
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1724671694448099328 |