Granular heap on an elastic membrane : statics and dynamics - Sophie Monnery (Institut Jean le Rond d’Alembert, Paris)

When granular material is poured onto an elastic membrane, it forms a heap whose weight deforms the membrane. The membrane’s deformation, in turn, constrains the heap’s geometry, causing its aspect ratio to deviate from the classic triangular profile. This coupling is governed by a dimensionless number that captures the balance between the membrane’s elasticity and the granular weight in this simplified elasto-granular system. We introduce an incremental model to predict the heap’s temporal evolution, accounting for its spreading and growth as mass is added.

Then, upon introducing energy into the system by vibrating the elastic support, grains rearrangements reshape the heap’s apex, giving rise to new configurations, including a “volcano-like” profile that is more compact. At even higher vibrational amplitudes, grains begin to detach from the bulk and to bounce on the membrane, with spiraling trajectories.

Contact: Philippe Marmottant