Effects of particle characteristics and consolidation pressure on the compaction of non-spherical particles

The mechanical strength of compacts depends on particle shape, materials properties as well as compaction conditions. This work presented a numerical study on the effects of interparticle friction, yield pressure of particles and consolidation pressure on the mechanical response of compacts formed of non-spherical particles. Non-convexity of the particle shape and interparticle bonding were explicitly considered in a model based on the Discrete Element Method (DEM). In unconfined uniaxial compression, the results showed that compressive strength of compacts increases with interparticle friction, consolidation pressure but decreases with yield pressure of particles. Larger inter-particle friction and consolidation pressure also lead to a more dispersed and uprising failure zones due to the inhomogeneous structure of compacts formed by die compaction. The non-convexity of particle and consolidation pressure enhanced the role of inter-particle friction in the compressive strength. However, failure mechanism during the unconfined compression showed no dependence on the particle characteristics and operational conditions as most of the bonds were broken by shearing. A large compressive strength was linked to an increased average bond size while a more dispersed bond failure corresponds to an increased proportion of horizontally aligned shear-induced bond failure.