论文标题

微重力的颗粒活塞涂料:粉末压缩,从致密到干扰

Granular piston-probing in microgravity: powder compression, from densification to jamming

论文作者

D'Angelo, Olfa, Horb, Anabelle, Cowley, Aidan, Sperl, Matthias, Kranz, W. Till

论文摘要

颗粒固体的宏观反应由力链的微观织物确定,这反过来又与固体史密切相关。为了询问重力对粉末流动性的影响,在封闭的容器,地下和微重力中,活塞会受到颗粒状材料的压缩。结果表明,活塞腐蚀使包装致密,最终导致了由活塞压缩的材料,而与重力环境无关。发现干扰的发作是在微重力中出现的($φ^{\ textrm {$μ$ -G}} _ j = 0.567 \ pm 0.014 $)($φ^{\ text {\ text {gnd}} _ j = 0.579 \ pm pm pm pm)。我们将这些发现解释为被重力场改变的颗粒织物的表现:在没有次级负载(由于引力加速度)的情况下,可以刺激与重大压缩应力的不同方向重组,颗粒的构型在较低密度下变得稳定,因为颗粒没有外部驱动力来促进重新组合养殖量。随着凝聚力相互作用的主要影响,这与在低重力下发生的界面力平衡的变化相结合。我们提出了微观论证和连续性论点的组合,以合理化我们的结果。

The macroscopic response of granular solids is determined by the microscopic fabric of force chains, which, in turn, is intimately linked to the history of the solid. To query the influence of gravity on powder flow-behavior, a granular material is subjected to compression by a piston in a closed container, on-ground and in microgravity. Results show that piston-probing densifies the packing, eventually leading to jamming of the material compressed by the piston, regardless of the gravitational environment. The onset of jamming is found to appear at lower packing fraction in microgravity ($φ^{\textrm{$μ$-g}}_J = 0.567 \pm 0.014$) than on-ground ($φ^{\text{gnd}}_J = 0.579 \pm 0.014 $). We interpret these findings as the manifestation of a granular fabric altered by the gravitational force field: in absence of a secondary load (due to gravitational acceleration) to stimulate reorganization in a different direction to the major compression stress, the particles' configuration becomes stable at lower density, as the particles have no external drive to promote reorganization into a denser packing. This is coupled with a change in interparticular force balance which takes place under low gravity, as cohesive interactions become predominant. We propose a combination of microscopic and continuum arguments to rationalize our results.

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