Publisher Summary This chapter focuses on an elementary numerical model that is able to quantitatively determine the internal cohesion of a three-dimensional agglomerate constituted of a couple of clusters on the basis of purely geometrical considerations. Three-dimensional clusters generated on cubic lattices may represent very fine grains when the grains develop very high surface roughness or powder of larger size when the fabrication method consists of the random agglomeration of smaller particles. Several techniques were found to lead to fractal aggregates. Several models were elaborated to interpret agglomerate cohesion phenomena on the basis of fragmentation (bulk fracture) or attrition (surface erosion) processes. The internal cohesion of the fractal agglomerate resulting from the encounter of two solid aggregates was investigated, taking into account (1) the number of its breakable inter-particle links, (2) the aggregate and the agglomerate masses, and (3) the fractal dimension of the aggregates. Powder agglomeration induced by physical forces or mediated by additives, and agglomerate fragmentation intervenes in a huge number of industrial, pharmaceutical, environmental and agricultural processes.