(418f) Compressed Dense Powder Blends: Size Dispersity and Void Structure

Using Discrete Element Method (DEM) simulatons (Dutt et al.,Comp. Phys. Comm.), we explore the effect of particle sizedistribution on the microstructure evolution of compressed densepowder packings. We consider four powder samples with discrete sizedistributions representative of pharmaceutical blends: 200 microns,195-225 microns , 170-260 microns, 150-295 microns. We generate thepowder packings by allowing the particles to settle under gravity fora fixed interval of time, or until a cut-off packing fraction isattained. The gravitationally settled powder is then uni-axiallycompressed at a constant strain rate for a fixed interval of time. Weobserve that higher compressive strains are required to attain a givenvalue of packing fraction, for increasing number of components in thepowder blends (Dutt et al., submitted). We also compute the voidstructure evolution via a dynamically tesselating algorithm whichcalculates the pore network in dense particulate systems. We find therange of pore volumes to increase with the number of components in theblend (Dutt et al., Physica A). Our approach can be used to designparticulate systems with a desired microstructural response tocompressive strains.