Résumé
Many materials manufactured by means of the ceramic processes (grinding, pressing, sintering), have agranular microstructure composed of cohesive aggregates of various shapes, including nonconvex shapes.In this work, we investigate the mechanical and microstructural properties of agglomerates composedof hexapod- shaped aggregates using an in-house DEM code. The aggregates are characterized by theiraspect ratio (ratio of their extension to thickness). By varying this parameter, the particle shape changesfrom sphere to thin hexapods. Spherical agglomerates are built by means of radial compaction for differentvalues of aspect ratio and friction coefficient. We investigate the influence of aspect ratio and frictioncoefficient on the microstructure and geometrical properties such as packing fraction, connectivity andelastic bulk modulus. We also investigate diametral compression of these agglomerates and we analyze indetail the strength and fracture behavior as a function of aspect ratio, friction coefficient, and cohesiveforce between aggregates for both reversible and irreversible cohesive interaction. We show that for largeenough aspect ratio, nonconvex shape considerably amplifies the cohesive strength of the agglomerate.