Numerical modelling of die and unconfined compactions of wet particles

A numerical method, based on the Discrete Element Method (DEM), is developed to simulate the closed-die compaction and unconfined compaction of wet granular materials. Elastic perfectly plastic are assumed for particles, local contacts are characterized by non-linear elastic and linear plastic deformation. The capillary force is explicitly considered. Solid bonds are introduced between contacting particles to account for the strength gain after closed-die compaction. The numerical model is described in detail. We also illustrate how the compact properties such as compressive strength and failure pattern are influenced by the bond strength and compaction pressure, which determine the mechanical and geometrical integrity of compact. The numerical results demonstrate a qualitative agreement with corresponding results from previous theoretical, experimental studies for the trend of stress-strain response and failure patterns under unconfined compaction. This study proves that solid bond model must be taken into account when modelling granular compaction process using DEM method.