Internal rolling method for particle shape evaluation and reconstruction

Abstract

A concise and robust method for 2D particle shape evaluation and reconstruction is proposed using the concept of the internal rolling of covering discs within the outline of a particle. By downscaling the covering disc size for capturing multiscale features, the calculation of the Euclidean distance can effectively yield three indices for sphericity, roundness and roughness. The geometric-based evaluations of particle morphology are dimensionless and precisely distinguishable between shapes after calibration and validation against constructed particles and natural sands. A sphericity-roundness diagram is provided to visualize the particle shape characterization, and a probabilistic density surface in the sphericity-roundness diagram is then proposed to statistically represent the distributions of the particle shapes. The concept of internal rolling is also utilized for particle shape reconstruction using a limited number of balls to replicate the indices of sphericity, roundness and roundness characteristic curve. The probabilistic density surface is duplicated for statistical particle shape reconstruction, which provides an effective approach for numerical investigations of the relationships between particle shapes and mechanical behavior. The effect of image quality on 2D shape evaluation is also examined by using a minimum area per particle, and the proposed method is intuitively extendable to 3D measurements using rolling covering spheres.

Surface textures of detrital pyroxenes in coastal dune sands (western Gulf of Mexico, Mexico): Implications for their preservation and geoenvironmental processes

“…Additional shape parameters like sphericity, convexity and roundness were obtained to observe any significant changes in the grain shape patterns of the clinopyroxenes and evaluate the value of the compactness parameter relative to more traditional approaches. Sphericity values were obtained following the sphericity index I s = A I / A , where A I is the area of the maximum inscribed circle obtained from the width of the particle (minimum radius) and A the particle area of the covering circle computed by the length of the particle (maximum radius; see Mo, 2020) (Table 1). Convexity values were obtained from the JMicrovision software descriptor shape output data based on the convexity hull (Zhao & Wang, 2016; Table 1).…”

Spatial Structure Characteristics of Underground Reservoir Water Storage Space in Coal Mines Considering Shape Characteristics of Crushed Rock

“…To investigate how different shapes of crushed rocks affect the spatial structural characteristics of underground reservoir water storage space in coal mines, it is essential to quantitatively characterize the shape of the crushed rock. In general, the particle shape can be quantitatively described in three scales: overall shape, angular features and surface texture [26]. The first scale indicators describe the overall shape characteristics of particles, including the long-to-medium axis ratio e, the medium-to-short axis ratio f and the sphericity ψ; the second scale indicator describes the angular characteristics of particles, which is usually expressed by the convexity C v ; and the third scale indicator describes the surface texture of particles, which is characterized by the roughness.…”

Spatio-temporal evolution laws of storage coefficient of coal mine underground reservoir and contact network of crushed rock

“…Therefore, this study introduces the concept of equivalent particle size D , which represents the spherical particle diameter that has the same volume as the measured particle. Previous methods for characterizing the shape of real particles have focused on overall shape, angular features, and surface texture, using multiple shape indicators [ 22 ]. However, these methods do not facilitate establishing a quantitative relationship between particle shape and its physical and mechanical properties [ 23 ].…”