Approach to structural anisotropy in compacted cohesive powder

We investigate the mesoscopic regime between microscopic particle properties and macroscopic bulk behavior and present a complementary approach of physical experiments and discrete element method simulations to explore the development of the microstructure of cohesive powders during compaction. On the experimental side, a precise micro shear tester ( μ ST ) for very small powder samples has been developed and integrated into a high resolution X-ray microtomography (XMT) system. The combination of μ ST and XMT provides the unique possibility to access the 3D microstructure and the particle network inside manipulated powder samples experimentally. In simulations we explore the structural changes resulting from compaction: a Hertzian contact model is utilized for compaction of an isotropic initial configuration created by a geometrical algorithm. As a first result of this approach we present the analysis of the compaction of slightly cohesive SiO 2 particles with special regard to bulk density, heterogeneity, compaction law and structural anisotropy.