Résumé
Despite the crucial role the agglomeration process plays in both nature and powder technology, the current understanding of the physical mechanisms determining the tensile strength of cohesive agglomerates consisting of fine particles is still limited. Specifically, the quantitative effects of particle shape in conjunction with cohesive-frictional interactions between particles have yet to be fully explained. One straightforward method to examine the influence of particle shape on the strength characteristics of granular materials is by employing hexapod-shaped particles. We used particle dynamics simulations to create agglomerates composed of hexapods and analyzed the effects of aspect ratio and interparticle friction on the force transmission and microstructure such as packing fraction, connectivity and elastic bulk modulus. We also investigate their mechanical behavior under diametral compression to showcase the effect of non-convex particle shape and interlocking on their tensile strength and we analyze the strength and fracture behavior as a function of aspect ratio, friction coefficient, and cohesive force between aggregates for irreversible cohesive interaction. We demonstrate that nonconvex form significantly increases the cohesive strength of the agglomeration for large enough aspect ratios. We show that the ability of thin hexapods to establish contact with their second neighbors and the function of friction in minimizing their disentanglement under diametral compression are connected with this amplifying effect of interlocking on the cohesive strength.