Pan Deng, Meng Fanlong, Jin Yuliang
CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China.
School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
PNAS Nexus. 2023 Feb 10;2(3):pgad047. doi: 10.1093/pnasnexus/pgad047. eCollection 2023 Mar.
The jamming transition, generally manifested by a rapid increase of rigidity under compression (i.e. compression hardening), is ubiquitous in amorphous materials. Here we study shear hardening in deeply annealed frictionless packings generated by numerical simulations, reporting critical scalings absent in compression hardening. We demonstrate that hardening is a natural consequence of shear-induced memory destruction. Based on an elasticity theory, we reveal two independent microscopic origins of shear hardening: (i) the increase of the interaction bond number and (ii) the emergence of anisotropy and long-range correlations in the orientations of bonds-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.
堵塞转变通常表现为在压缩下刚性的快速增加（即压缩硬化），在无定形材料中普遍存在。在这里，我们通过数值模拟研究了深度退火的无摩擦堆积中的剪切硬化，报告了压缩硬化中不存在的临界标度。我们证明硬化是剪切诱导记忆破坏的自然结果。基于弹性理论，我们揭示了剪切硬化的两个独立微观起源：（i）相互作用键数的增加和（ii）键取向中各向异性和长程相关性的出现——后者突出了压缩硬化和剪切硬化之间的本质区别。通过建立特定于各向异性的物理定律，我们的工作完善了堵塞转变的临界性和普遍性以及无定形固体的弹性理论。
