An experimental evaluation of the accuracy to simulate granule bed compression using the discrete element method

In this work, granule compression is studied both experimentally and numerically with the overall objective of investigating the ability of the discrete element method (DEM) to accurately simulate confined granule bed compression. In the experiments, granules of microcrystalline cellulose (MCC) in the size range 200–710 μm were used as model material. Unconfined uniaxial compression of single granules was performed to determine granule properties such as the yield pressure and elastic modulus and compression profiles of the MCC granules were obtained from granule bed compression experiments. By utilizing the truncated Hertzian contact model for elastic-perfectly plastic materials, the rearrangement and plastic deformation stages of the force displacement curve were found to be in reasonable agreement with experiments. In an attempt to account for the final compression stage, elastic deformation of the compact, a simple modification of the contact model was proposed. This modification amounted to the introduction of a maximal plastic overlap, beyond which elastic deformation was the only deformation mode possible. Our results suggest that the proposed model provides an improved, although not perfect, description of granule bed compression at high relative densities and hence may be used as a basis for future improvements.

The ability of the discrete element method to simulate granule bed compression was investigated. A reasonable agreement with experimental data was observed during the initial stages of compression (rearrangement and plastic particle deformation) but a modified contact model was necessary to satisfactorily describe the final stage (elastic compact deformation). Such a modified contact model was presented.Figure optionsDownload as PowerPoint slideHighlights
► The ability of the DEM to simulate granule bed compression was investigated.
► A reasonable agreement was observed during the initial stages of compression.
► A modified contact model was necessary to satisfactorily describe the final stage.
► Such a modified contact model was presented.