(666d) Analysis of Non-Linear Tensile Strength Variation In Binary Mixtures Using Multi-Particle Finite Element Method (MPFEM)

Pharmaceutical tablets are comprised of a mixture of powders with varying properties. To predict the compaction performance of a drug formulation, it is essential to understand the interaction between the constituents of a mixture that will affect the bulk mechanical properties of the resulting mixture. It has been observed experimentally that mechanical properties of a mixture vary non-linearly with the mass fraction of the constituents, and this non-linear interaction could be either positive or negative. Hence, it is difficult to predict the bulk mechanical properties of mixtures, e.g., tensile strength and Young’s Modulus, using simple linear mixing rules. Previous researchers have tried both experiments and analytical models to comprehend the causes of this observed non-linearity but have been unable to provide a proper explanation of it.

The multi-particle finite element method (MPFEM) is used to study the micromechanics of particle interactions and their effect on the macroscopic mechanical properties of binary mixtures. In MPFEM, the particles are modeled in the FEM framework with a given set of material and contact properties. The particles can deform based on the applied boundary conditions and contact interactions. Although the current MPFEM models cannot quantitatively predict the bulk mechanical properties of a mixture,they can give a reasonable explanation behind the experimentally observed non-linear behavior. This talk will focus on analyzing the variation of tensile strength in binary mixtures. Simulations will also be compared to experimental results.