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Shear hardening in frictionless amorphous solids near the jamming transition

SourceSeminar Date of Publication:Aug 25,2022
08/25 2022 Seminar
  • Title Shear hardening in frictionless amorphous solids near the jamming transition
  • Speaker 潘登 (中科院理论物理研究所)
  • Date 2022年8月25日 16:00
  • Venue 腾讯会议:311-446-958
  • Abstract

    The jamming transition, generally manifested by a rapid increase of rigidity under compression (i.e., compression hardening), is ubiquitous in amorphous materials. Despite isotropic compression, matters can also gain rigidity under shear strain. Here, we perform comprehensive numerical and theoretical analysis on the shear hardening (increase of modulus under shear strain) behaviors of amorphous solids. The shear hardening is characterized by two scaling laws, the excess coordination number DZ scales with s2/5 and the macroscopic friction coefficient m scales with s1/4 for harmonic repulsive model. The former is consistent with the scaling ansatz for isotropic compression hardening. While, the latter is unique to shear. We demonstrate that shear hardening is a natural consequence of shear-induced memory destruction. Deducing from the generalized phase diagram of jamming, we uncover two microscopic origins of shear hardening, increasing of contacting number and anisotropy. A theoretical analysis indicates that the coordination number and the spacial correlation between contacts, that quantified by anisotropy, contribute to the shear modulus independently. The latter highlights the essential difference between compression and shear hardening. Through the establishment of physical laws specific to anisotropy, our work completes the criticality and universality of jamming transition, and the elasticity theory of amorphous solids. In the last part of this talk, I will discuss the possibility of shear hardening in poorly annealed and frictional systems, and outlooks inspired by our results.


    Configuration, long-range bond orientation correlations and rigidity of anisotropic amorphous solids.