Microscopic reversibility and emergent elasticity in ultrastable granular systems

• DOI: 10.3389/fphy.2022.1048683
• Publication Date: 2022-11-28T05:40:23Z
• Authors: Yiqiu Zhao; Yuchen Zhao; Dong Wang; Hu Zheng; Bulbul Chakraborty; Joshua E. S. Socolar
• Keywords: Shear modulus; Elasticity; Scaling law

In a recent paper (Zhao et al., Phys Rev X, 2022, 12: 031,021), we reported experimental observations of “ultrastable” states in shear-jammed granular system subjected to small-amplitude cyclic shear. such states, all the particle positions and contact forces are reproduced after each shear cycle so that strobed image stresses appears static. present work, report further analyses data from those experiments characterize both global local responses ultrastable within cycle, not just dynamics. We find follow power-law relation between modulus pressure with an exponent β ≈ 0.5, reminiscent critical scaling laws near jamming. also examine evolution measured using photoelasticimetry. there two types contacts: non-persistent contacts reversibly open close; persistent never display no measurable sliding. show make non-negligible contribution emergent modulus. analyze spatial correlations stress tensor compare them predictions theory elasticity solids, Vector Charge Theory Granular mechanics dynamics (VCTG) (Nampoothiri Lett, 2020, 125: 118,002). our results can be fit well by VCTG, assuming uniaxial symmetry networks. The fits reveal response additional applied is substantially more isotropic than original states. Our provide important insight into mechanical properties frictional solids created