Advancing simulation of large deformation adhesive elasto-plastic powder compaction

Powder compaction is widely used in critical industrial processes such as pharmaceutical tableting and electrode calendaring in battery manufacturing. However, a complete understanding of the underlying physical mechanisms that govern pore structure, mechanical strength, and defects remains elusive. Due to the opaque nature of powders, numerical techniques have gained favor to provide microscopic, per-particle insights that dictate compact properties. In this talk, we focus on developing a discrete description of powder behavior using the discrete element method (DEM). Specifically, we implement a recently published, mechanically-derived, large deformation adhesive elastic-plastic normal force model (MDR contact model) into the open-source DEM software LAMMPS. The industrially relevant problem of pharmaceutical tableting is simulated, and comparisons to experimental data for the compaction of Avicel PH102 (microcrystalline cellulose) are made. We observe good agreement between the experiment and simulation for both axial and radial stress measurements as a function of axial strain. Notably, the simulation predicts a similar residual radial stress after release of the axially confining pressure and ejection force to that of the experiment. We also discuss special considerations for large deformation DEM and highlight the unique particle reconstruction capabilities of the MDR contact model, comparing directly to predictions made by the multi-particle finite element method.