Experimental study of granular materials composed of platonic polipods: exploring geometric cohesion and solid fraction

In this study, we explored the stability and compactness of columns formed from highly irregular particles. These particles, known as Platonic polypods, are fashioned by extruding arms onto the faces of Platonic solids, for which we systematically varied the number and thickness of these arms. We investigated the emergence and vanishing of geometric cohesion (i.e., solid-like characteristics, in the absence of adhesive forces among particles). We first built columns by depositing particles within a cylindrical container, which was then removed to assess the structure’s stability. Experiments employing three different materials discerned the impact of the friction coefficient between grains. Our results show that specific granular systems manifest geometric cohesion, depending upon their geometric and contact attributes. Furthermore, we measured the initial solid fraction of the columns, illustrating their capacity to attain stability even in markedly loose configurations.