Multi-super-ellipsoid model for non-spherical particles in DEM simulation

Evolution characteristics of micromechanics provides insights into the microstructure of pharmaceutical tablets fabricated by bimodal mixtures

This research focuses on the evolution of mechanical behavior of bimodal mixtures undergoing compaction and diametrical compression. The clusters were built and discrete element method (DEM) was used to investigate the densification process and micromechanics of bimodal mixtures. Additionally, a more comprehensive investigate of the respective breakage of the bimodal mixtures has been carried out. On this basis, qualitative and quantitative analysis of the compressive force, force chain, contact bonds and density field evolution characteristics of the clusters are investigated during the compression process. The entire loading process of the clusters is divided into three stages: rearrangement, breakage and elastic-plastic deformation. Additionally, there are differences in the evolution of micromechanics behavior of different particles in the bimodal mixture, with pregelatinized starch breakage and deformation occurring before microcrystalline cellulose. With the tablet deformation, the fragmentation process of the tablet started at the point of contact and extended toward the center, and the curvature of the force chain increased. This approach may potentially hold a valuable new information relevant to important transformation forms batch manufacturing to advanced manufacturing for the oral solid dosage form.

3D DEM Simulations and Experiments on Spherical Impactor Penetrating into the Elongated Particles

In this study, a brass or glass spherical impactor vertically penetrating into a granular bed composed of mono-sized spherical or elongated particles was simulated with three-dimensional (3D) discrete element method (DEM). Good agreement of the particle masses in the cup before and after penetration can be found in the simulations and experiments. The effects of particle length (L_p), friction coefficient, and particle configuration on the penetration depth of the impactor, ejecta mass, and solid volume fraction describing the response of the granular bed are discussed. The penetration depth is negatively correlated with L_p as the corresponding solid volume fraction of the granular bed decreases. A smaller friction coefficient leads to a larger penetration depth of the impactor and more ejection of particles. When the impactor is penetrating the L_p = 10 mm elongated particles, the penetration depth is negatively correlated to the order parameter and solid volume fraction.

DEM study of the angle of repose and porosity distribution of cylindrical particles with different lengths

Effect of the length of cylindrical particle on repose angle and porosity of a pile was numerically studied using discrete element method. The variation of repose angle and porosity with coefficient of sliding and rolling friction were also discussed. The results shown that compared with sphere particle, the bottom size of cylindrical pile is smaller, while the height of cylinder pile is larger and the heap is steeper. With the increase of the length of cylinder, the contour line of the pile becomes steep, and the angle of repose increases. The repose angle shows a positive correlation with coefficient of sliding and rolling friction. The porosity increases with the increase of the length of cylinders. The trends of porosity are basically consist with that of repose angle, and with increase of friction coefficient, the average porosity increases.