Micromechanical investigation of the fracture behavior of powder materials

Fracture of compacted powder has been studied experimentally and numerically using a micromechanical approach. In the experimental investigation, the compacts are crushed in two different directions to account for general stress states and a microscopy study shows that fracture of the powder granules plays a significant role in the fracture process. The numerical analysis is based on the Discrete Element Method (DEM) and a novel approach is presented to account for the fracture of the particles in the numerical model. The force-displacement relations for two particles in contact, which are needed in DEM, are derived using micomechanical experiments together with finite element analyses of the contact problem. The contact model accounts for plastic compression, elastic unloading and adhesive bonding together with friction and tangential bonding. The model shows a very good agreement with the experimental data both for the elastic behavior during unloading and, if failure of the particles is accounted for, the fracture of the compacts. (C) 2015 Elsevier B.V. All rights reserved.