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ja_elliott1_2015

Compaction and flow of organic crystalline powder materials

The performance of materials manufactured by powder compaction is crucially dependent on a detailed understanding of the relationship between the size, shape and mechanical properties of the constituent powders and the characteristics of the final compact. The approach in this project is to use a combination of experimental compaction simulation and discrete element models to parameterise appropriate constitutive equations (e.g. the density-dependent Drucker-Prager cap model) for the powders, which can then be used in finite element simulations of the compaction process. The discrete element models incorporate well-defined elastic moduli and contact force models, including friction to couple the rotational and translational degrees of freedom of the particles. The framework can be extended to model frangible granules of arbitrary shape undergoing uniaxial or triaxial compression and simple shear. The finite element simulations encompass process parameters, such as punch shape, die geometry and compaction speed. The overall aim is to link the molecular scale properties of the constituents to the mesoscale powder properties, and ultimately to predict the stress and density distributions in the final compact.