Evaluation of bulk compression using a discrete element procedure calibrated with data from triaxial compression experiments on single particles
Confined compression of bimodal mixtures of nearly monodisperse spherical cellulose acetate (CA) particles (diameters 1.5 and 2.0 mm) was studied numerically with the discrete element method (DEM) and experimentally using a materials tester equipped with suitable tablet tooling. An extended truncated sphere contact model was used in the simulations, enabling them to be carried out to high relative densities (approaching and sometimes exceeding unity). In order to calibrate this model, the contact pressure development was extracted from prior experimental investigations on single 2.0-mm large CA particles. Results from the simulations were evaluated with the Kawakita and Heckel compression equations and compared to the corresponding data obtained from bulk compression experiments. Generally, a high degree of similarity between experiments and simulations was observed, showing the usefulness of combining confined single particle compression experiments with a suitable numerical model when predicting the performance of powder compression to high relative densities.