Universality of slip avalanches in flowing granular matter.
Universality of slip avalanches in flowing granular matter.
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DOI：
10.1038/ncomms10641
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发表时间：
2016-02-17
影响因子：
16.6
通讯作者：
Schall P
中科院分区：
文献类型：
--
作者：
Denisov DV;Lörincz KA;Uhl JT;Dahmen KA;Schall P
非晶材料变形中尺度桥接关系的研究在材料科学、工程和地质学中有着广泛的应用。虽然流动和微观动力学的一般特征支持变形的普遍标度理论的想法，但直接的微观证据仍然很差。在这里，我们提供了第一个测量的内部标度关系的颗粒物质的变形。通过结合宏观力波动测量与内部应变成像，我们证明了从粒子尺度到宏观流动的鲁棒标度关系的存在。我们确定一致的幂律关系截断系统的压力相关的截止，与最近的平均场理论的滑动雪崩在弹塑性材料，揭示了存在的力学临界点。这些结果通过实验建立了物质流动中的尺度桥接关系，为新的通用变形理论铺平了道路。 无定形材料的变形是否受普适标度（临界现象的一个特征）的控制，目前仍有争议。在这里，Denisov等人通过将微观尺度的内部应变与所施加力的波动联系起来提供了实验证据。
The search for scale-bridging relations in the deformation of amorphous materials presents a current challenge with tremendous applications in material science, engineering and geology. While generic features in the flow and microscopic dynamics support the idea of a universal scaling theory of deformation, direct microscopic evidence remains poor. Here, we provide the first measurement of internal scaling relations in the deformation of granular matter. By combining macroscopic force fluctuation measurements with internal strain imaging, we demonstrate the existence of robust scaling relations from particle-scale to macroscopic flow. We identify consistent power-law relations truncated by systematic pressure-dependent cutoff, in agreement with recent mean-field theory of slip avalanches in elasto-plastic materials, revealing the existence of a mechanical critical point. These results experimentally establish scale-bridging relations in the flow of matter, paving the way to a new universal theory of deformation. Whether the deformation of amorphous materials is governed by universal scaling, a characteristic feature of the critical phenomena, is currently under debate. Here, Denisov et al. provide experimental evidence by linking the internal strains at microscales to the fluctuations in the applied force.