Citation

Li, Y., Otsubo, M., Kuwano, R., Nadimi, S. (2021). Quantitative evaluation of surface roughness for granular materials using Gaussian filter method. Powder Technology, 388: 251-260. Link to paper

Abstract

This contribution proposes a methodology to measure the surface roughness of granular materials using the Gaussian filter. Artificially generated rough surfaces with known root mean square roughness (S_q) combined with the spherical shape are analysed to determine the optimum cut-off wavelength (σ*) adopted in the Gaussian filter. Considering a combined dependency of S_q and particle size (D) on σ*, an empirical regression equation is derived to describe their relationship. The regression equation is further found to be applicable for granular materials including glass beads and natural sand grains with irregular base shapes. To implement the proposed Gaussian filter method into practical use, a detailed guideline is given to determine S_q including the selection of representative measurement area. Finally, quantitative comparisons of S_q are made to distinguish the difference between the proposed method and motif method.

Highlights

• A Gaussian filter method is proposed to evaluate the surface roughness.
• A calibration process is developed to obtain the optimum cut-off wavelength (σ*).
• A guidance is introduced to apply the proposed method in practical use.
• Criteria are given to select a suitable measurement area of irregular particles.
• Quantitative comparisons with the motif method are made.