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Force Mobilization and Generalized Isostaticity in Jammed Packings of Frictional Grains

Kostya Shundyak·Martin van Hecke·Wim van Saarloos
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Abstract

We show that in slowly generated 2d packings of frictional spheres, a significant fraction of the friction forces lies at the Coulomb threshold - for small pressure p and friction coefficient mu, about half of the contacts. Interpreting these contacts as constrained leads to a generalized concept of isostaticity, which relates the maximal fraction of fully mobilized contacts and contact number. For p->0, our frictional packings approximately satisfy this relation over the full range of mu. This is in agreement with a previous conjecture that gently built packings should be marginal solids at jamming. In addition, the contact numbers and packing densities scale with both p and mu.

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Kostya Shundyak, Martin van Hecke, Wim van Saarloos. 2006-10-07. Force Mobilization and Generalized Isostaticity in Jammed Packings of Frictional Grains. https://doi.org/10.1103/physreve.75.010301

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