论文标题

摩擦颗粒物:机械性能的方案依赖性

Frictional Granular Matter: Protocol Dependence of Mechanical Properties

论文作者

Lemaître, Anaël, Mondal, Chandana, Procaccia, Itamar, Roy, Saikat, Wang, Yinqiao, Zhang, Jie

论文摘要

摩擦粒状物质的理论处理通常认为,援引经典弹性理论来描述其粗粒的机械性能是合理的。在这里,我们根据实验和数值模拟表明,这种情况并非如此,因为应力自动相关功能比弹性绿色的功能更慢。从理论上讲,标准弹性衰减需要压力和扭矩密度波动正常,其中一个可能是非常均匀的。通用压缩摩擦组件表现出异常的压力波动,未能符合中心极限定理。该故障的物理学与在干扰之前从稀释配置压缩过程中材料中内置的相关性有关。通过更改压缩方案,可以观察到不同的压力波动和应力自动相关的大规模衰减。

Theoretical treatments of frictional granular matter often assume that it is legitimate to invoke classical elastic theory to describe its coarse-grained mechanical properties. Here we show, based on experiments and numerical simulations, that this is generically not the case since stress auto-correlation functions decay more slowly than the elastic Green's function. It was shown theoretically that standard elastic decay demands pressure and torque density fluctuations to be normal, with possibly one of them being hyperuniform. Generic compressed frictional assemblies exhibit however abnormal pressure fluctuations, failing to conform with the central limit theorem. The physics of this failure is linked to correlations built in the material during compression from a dilute configuration prior to jamming. By changing the protocol of compression one can observe different pressure fluctuations and stress auto-correlations decay at large scales.

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