
Publications [#335572] of Robert P. Behringer
Papers Published
 Wang, D; Ren, J; Dijksman, JA; Zheng, H; Behringer, RP, Microscopic Origins of Shear Jamming for 2D Frictional Grains.,
Physical Review Letters, vol. 120 no. 20
(May, 2018),
pp. 208004 [doi]
(last updated on 2019/02/20)
Abstract: Shear jamming (SJ) occurs for frictional granular materials with packing fractions ϕ in ϕ_{S}<ϕ<ϕ_{J}^{0}, when the material is subject to shear strain γ starting from a forcefree state. Here, ϕ_{J}^{μ} is the isotropic jamming point for particles with a friction coefficient μ. SJ states have mechanically stable anisotropic force networks, e.g., force chains. Here, we investigate the origins of SJ by considering smallscale structurestrimers and brancheswhose response to shear leads to SJ. Trimers are any three grains where the two outer grains contact a center one. Branches occur where three or more quasilinear force chain segments intersect. Certain trimers respond to shear by compressing and bending; bending is a nonlinear symmetrybreaking process that can push particles in the dilation direction faster than the affine dilation. We identify these structures in physical experiments on systems of twodimensional frictional discs, and verify their role in SJ. Trimer bending and branch creation both increase Z above Z_{iso}≃3 needed for jamming 2D frictional grains, and grow the strong force network, leading to SJ.
