Numerical simulation on pharmaceutical powder compaction

In this paper, we present a modified density-dependent Drucker-Prager Cap (DPC) model with a nonlinear elasticity law developed to describe the compaction behavior of pharmaceutical powders. The model is implemented in ABAQUS with a user subroutine. Using microcrystalline cellulose (MCC) Avicel PH101 as an example, the modified DPC model is calibrated and used for finite element simulations of uniaxial single-ended compaction in a cylindrical die. To validate the proposed model, finite element simulation results of powder compaction are compared with experimental results. It was found that finite element analyses gave a good prediction of both the loading-unloading curves during powder compaction and the compaction force required for making a tablet with a specified density. Further, the failure mechanisms of chipping, lamination and capping during tabletting are investigated by analysing the stress and density distributions of powders during the three different phases of the tabletting processes, i.e. compression, decompression and ejection. The results indicate that the model has excellent potential to describe the compaction process for generic pharmaceutical powders.