Constitutive Model for Dry Cohesive Powders with Application to Powder Compaction

Constitutive Equation for Powder Compaction Incorporating Powder Charecteristics

The increasing importance of powdered materials fabrication has led to an increasing emphasis on the understanding of the powder behavior during compaction. During compaction, a powder mass undergoes densification owing to various mechanisms, i.e. sliding, rotation, deformation and/or fracturing of the constituent particles. These densification mechanisms are very dependent upon the powder char...

1 Powder Compaction by Dry Pressing

Element Test Experiments and Simulations: from Dry towards Cohesive Powders

Findings from experiments and particle simulations for dry and cohesive granular materials are presented with the goal to reach quantitative agreement between simulations and experiments. Results for the compressibility, tested with the FT4 Powder Rheometer are presented. The first simulation results involve the strain controlled uniaxial compression of frictionless polydisperse spheres in a bi...

Numerical and Experimental Investigation of Yielding for Cohesive Dry Powder

We study the effect of particle cohesion on the steady state shear strength of a granular material. For cohesive powders, the steady state shear loci (termination loci) from DEM simulations are nonlinear with a peculiar pressure dependence due to the non-linear increase of contact adhesion with pressure in the contact model. Physical experiments are carried out on fine limestone powder in the d...

Magnetically mediated flow enhancement for controlled powder discharge of cohesive powders

A new flow enhancement system is developed for cohesive powders. It is based on the concept of multiple, point source, internal excitations. In this system, a mass of small permanent-magnetic particles are placed in the discharge zone of a hopper, and then an oscillating magnetic field is applied to excite these magnets. A screen is placed at the exit to keep the magnets within the hopper. The ...