Kim Sangwoo, Hilgenfeldt Sascha
Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Mechanical Science and Engineering, University of Illinois, Urbana-Champaign, Illinois 61801, USA.
Soft Matter. 2024 Jul 17;20(28):5598-5606. doi: 10.1039/d4sm00426d.
Understanding the way disordered particle packings transition between jammed (rigid) and unjammed (fluid) states is of both great practical importance and strong fundamental interest. The values of critical packing fraction (and other state variables) at the jamming transition are protocol dependent. Here, we demonstrate that this variability can be systematically traced to structural measures of packing, as well as to energy measures inside the jammed regime. A novel generalized simultaneous particle swap algorithm constructs overjammed states of desired energy, which upon decompression lead to predictable critical packing fractions. Thus, for a given set of particle sizes, states with extraordinarily high critical packing fractions can be found efficiently, which sustain substantial shear strain and preserve their special structure over the entire jammed domain. The close relation revealed here between the energy landscape of overjammed soft-particle packings and the behavior near the jamming transition points towards new ways of understanding and constructing disordered materials with exceptional properties.
理解无序颗粒堆积在堵塞（刚性）状态和非堵塞（流体）状态之间的转变方式，具有重大的实际意义和强烈的基础研究价值。堵塞转变时的临界堆积分数（以及其他状态变量）的值取决于实验方案。在此，我们证明这种变异性可以系统地追溯到堆积的结构度量，以及堵塞状态下的能量度量。一种新颖的广义同时粒子交换算法构建了具有所需能量的过堵塞状态，解压后会导致可预测的临界堆积分数。因此，对于给定的一组颗粒尺寸，可以高效地找到具有极高临界堆积分数的状态，这些状态在整个堵塞区域内承受大量剪切应变并保持其特殊结构。此处揭示的过堵塞软颗粒堆积的能量景观与堵塞转变点附近行为之间的密切关系，为理解和构建具有特殊性质的无序材料指明了新方向。
