Numerical studies of uniaxial powder compaction process by 3D DEM

In this paper, a 3D DEM program TRUBAL, which is capable of calculating the contact between particles considering friction and local plastic deformation, is employed to study the evolution of internal structure of particle assemblies during the consolidation process. Uniaxial powder compaction process is simulated in a cubic periodic unit cell by applying the strain rate to the individual particles. The selection of the proper time steps in DEM for quasi-static case is discussed. Results in particle scale (microscopic) are obtained and correlated to the statistical bulk response of the assembly. The effects of the microscopic properties of particles (such as friction, plastic contact) on the bulk mechanical response are examined by numerical tests. Correlations between the microscopic properties of particles and the macroscopic continuum behaviours of compacts are discussed. These discussions make it possible to fit DEM results at a macroscopic scale to the experimental measurements by adjusting the particle properties in DEM calculation. An example test is carried out to demonstrate that DEM results could be fitted properly to the experimental results, in the mean time, also provide some microscopic results which are hard to be measured. DEM has the potential to incorporate the microscopic properties of particles into a proper continuum model to perform combined macro and micro study of the powder compaction process.