(144d) Calibration of DEM Parameters for Cohesive Powders Using an Annular Shear Cell

Discrete Element Method (DEM) modeling of particulate flows is becoming increasingly common for designing, troubleshooting, and optimizing industrial processes. Creating an effective DEM model requires an efficient methodology to calibrate material properties. In this work, a DEM parameter calibration strategy for cohesive powders is proposed, specifically for particle-particle sliding friction and particle-particle cohesive surface energy density. This method involves using a single, common bulk powder flow testing device, the shear cell, to obtain predictions of incipient yield loci and critical state loci for a range of DEM parameters with simulations planned using design of experiments. Dimensional analysis is used to further reduce this parameter space and increase the generality of the results. The simulation results are analyzed to find the statistically significant parameters, and any major interaction effects between two parameters which are then used to create a predictive model using regression. These predictions are compared with the experimental values to determine the appropriate DEM particle parameter values. The effects of particle size distribution, shear cell pre-consolidation stress, particle-particle sliding friction, particle-particle cohesive surface energy density, and particle aspect ratio on the shear cell bulk behavior as predicted by DEM are also explored. These DEM parameters, calibrated for three different pharmaceutical materials, are validated by modelling an independent system and comparing the results to those from experiments.