Link between single-particle properties and macroscopic properties in particulate assemblies: role of structures within structures
Link between single-particle properties and macroscopic properties in particulate assemblies: role of structures within structures
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DOI：
10.1098/rsta.2007.0004
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发表时间：
2007-12-15
期刊：
影响因子：
5
通讯作者：
Antony, S. J.
中科院分区：
文献类型：
--
作者：
Antony, S. J.
颗粒材料在现代工业过程和产品中的普遍存在为实现对颗粒介质的整体行为的基本理解提供了重要的动机。原子力显微镜和相关颗粒表征技术的快速进展推动了微米和纳米技术的极限，使得可以设计颗粒间相互作用来制造颗粒组装体以提供特定功能。在本文中，主要是基于离散元方法模拟，我们在过去的10年里，我们总结了力传递网络的作用，受到剪切的致密颗粒系统的关键发现。一般而言，颗粒系统中的宏观强度特性由重载接触的分布决定，也称为“强”力链。令人惊讶的是，它们仅构成颗粒系统中所有接触的有限比例。它们就像一个粒子级的“颗粒大脑”（记忆网络）。我们表明，力链的结构安排和它们在加载过程中的演变取决于单颗粒的性能和颗粒组装的初始包装条件。此外，剪切颗粒介质中力链的“性质”诱导较大的“固体”颗粒表现得像“流体”颗粒，延缓其破碎。后来，我们探索的方式，我们可以控制的签名的记忆网络在填充床，例如通过施加外部电场在密集填充的颗粒床受到剪切（组合机电负载）。虽然需要进一步的研究来解释更现实的条件，最好是让颗粒自组织到强度规格，但了解颗粒材料中隐藏的记忆网络可以用来优化它们的集体强度。
The prevalence of particulate materials in modern industrial processes and products provides a significant motivation to achieve fundamental understanding of the bulk behaviour of particulate media. The rapid progress being made with atomic force microscopy and related particle characterization techniques pushes the limits of micro- and nanotechnologies such that interparticle interactions can be engineered to fabricate particulate assemblies to deliver specific functionalities. In this paper, primarily based on discrete element method simulations that we performed over the past 10 years, we summarize the key findings on the role of force transmission networks in dense particulate systems subjected to shearing. In general, the macroscopic strength characteristics in particulate systems is dictated by the distribution of heavily loaded contacts, also referred to as 'strong' force chains. Surprisingly, they constitute only a limited proportion of all contacts in particulate systems. They act like a 'granular brain' ( memory networks) at particle scale. We show that the structural arrangement of the force chains and their evolution during loading depends on the single-particle properties and the initial packing condition in particulate assemblies. Further, the 'nature' of force chains in sheared granular media induces larger 'solid' grains to behave like 'fluid' particles, retarding their breakage. Later, we probe for ways by which we can control the signature of memory networks in packed beds, for example by applying an external electrical field in a densely packed particulate bed subjected to shearing ( combined electromechanical loading). Though further research is required to account for more realistic conditions and preferably to allow particles to self-organize to strength specifications, understanding the hidden memory networks in particulate materials could be exploited to optimize their collective strength.