Impact of the heap shape formation on the local vertical force profile of ensiled granular materials

Agnès Duri-Bechemilh (1) , Frederic Mabille (1) , Thierry Ruiz (1)

1 UMR IATE - Ingénierie des Agro-polymères et Technologies Émergentes

The free surface, which results from the filling of a container by a dry granu- lar material, takes the shape of a heap. This shape is induced by the particle properties like their size, their friction, their restitution coefficient but also by their kinetic energy induced by the filling conditions. The stabilization of the intergranular contact network inside the heap leads to the formation of a spe- cific local stress field. For five wheat-based powders of same origin but with contrasted properties, beds are formed in a 2D semi-confined cell using a point source. Captures of the bed free surface are realized from pictures taken at different filling states. The local vertical force is measured in the center of the cell at different depths. This work highlights a correlation between the local vertical force profile and the shape of the heap during the filling. Two modes of force distribution can be distinguished and classified according to a parameter of uniformity. These distinctions are linked to the different shapes of the heap, quasi-layering or dune. Our experimental study demonstrates that the history of the powder filling directly impacts on the resulting local force profile.

Mots clés: Ensiled granular medium; Vertical force profile; Heap free surface; Wheat-based powders; granular structure

Mots clés: comportement mécanique; poudre alimentaire; structure granulaire

Domaines: Autre [cond-mat.other]

Agnès Duri-Bechemilh, Frederic Mabille, Thierry Ruiz. Impact of the heap shape formation on the local vertical force profile of ensiled granular materials. Powder Technology, 2018, 338, pp.993-1000. ⟨10.1016/j.powtec.2018.06.046⟩. ⟨hal-01604246⟩