Paper Number
SC11 

Session
Suspensions, Colloids, and Granular Materials

Title
Shear induced geometry and jamming in sphere packings

Presentation Date and Time
October 11, 2021 (Monday) 4:10

Track / Room
Track 5 / Ballroom 6

Authors (Click on name to view author profile)

  1. H A, Vinutha (Georgetown University, Institute for Soft Matter Synthesis and Metrology)
  2. Sastry, Srikanth (Jawaharlal Nehru Center for Advanced Scientific Research, Theoretical Sciences Unit)

Author and Affiliation Lines (in printed abstract book)
Vinutha H A1 and Srikanth Sastry2
1Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC; 2Theoretical Sciences Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Bangalore, Karnataka, India

Speaker / Presenter 
H A, Vinutha

Keywords
computational methods; granular materials

Text of Abstract
Rigidity or jamming in amorphous sphere assemblies can be induced by compression or by shear deformation. In frictionless sphere packings,jamming occurs at the packing fraction of 64%, also known as random close packing density (RCP). In the presence of friction, jamming can occur below RCP when subjected to compression or shear deformation. Here, we show shear deformation leads to geometrical features that are characteristic of jammed packings at RCP for a wide range of densities below RCP in frictionless packings. We test the mechanical stability of shear deformed frictionless packings, with and without the inclusion of frictional forces, to understand the distinct roles played by shear deformation & friction in shear jamming phenomenology. Unique to shear jamming is the geometric criterion on the contact number Z for jamming, i.e., the average contact number Z = D + 1, where D is the spatial dimensionality. This condition is independent of friction coefficient, spatial dimensions, and jamming protocols. In two dimensions, Using rigidity percolation analysis, we identified that the percolation of over-constrained (or rigid+stress or self-stress) regions corresponds to the shear jamming transition. These regions transmit stress across the packing.