Acoustics and frictional sliding in granular materials
Résumé
We study numerically the propagation of an acoustic pulse through a loaded granular material under the hypothesis that the conventional modeling of solid friction used in soft sphere discrete element mod-eling remains valid at acoustic time scales. As a pulse crosses the material, it temporarily suppresses sliding contacts, making it difficult to prepare states that correspond to experimental conditions. The pulse speed is strongly affected by the loading in a very anisotropic way, varying by as much as a factor of two depending on the propagation direction. We separate the contribution of the contact network from that of sliding contacts , and show that sliding contacts can reduce the propagation speed as much as changes in coordination number. Sliding contacts have a characteristic acoustic signature: pulse speed depends on sign (compression or rarefaction), even at very small amplitudes.
Domaines
Physique [physics]
Origine : Fichiers produits par l'(les) auteur(s)
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