Three-dimensional morphological characteristics of particles in nature and its application for DEM simulation

The particle's shape is one of the important factors affecting the physical and mechanical behaviors of granular materials. To study the morphological characteristics, the 3D point cloud of the surface of three kinds of particles in relation to different formations (including large scale rock blocks formed by two landslides, artificial crushed rock blocks and little sand particles) with different sizes in nature are obtained by using laser scanning and computed tomography (CT). Subsequently, a reconstruction method based on a spherical harmonic function is provided to automatically and accurately reconstruct the 3D model of each particle based on the point cloud of their surfaces. From this, a database of each particle's 3D model has been built, and of which six morphological parameters of the particles are statistically analyzed. The correlation between these parameters are studied, which proved a strong linear correlation between VESD-V/S, S-Cx and S-SR of any kind of particle. The results show that the particle's formation will have a great influence on the particle's shape, and a multi-factor “DNA” series of particles have been suggested, such as VESD-S-R, or VESD-Cx (SR) -R, or V/S-S-R, or V/S-Cx (SR) -R. Finally, discrete element method (DEM) is used to study the influence of the representing accuracy of the particles' model on the numerical results, which shows that considering the simulation effect and calculation efficiency, the face number value with surface area error lower than 15% are well for characterizing the model of the particles.