密集颗粒物质的多尺度结构

THE MULTISCALE STRUCTURE OF DENSE GRANULAR MATTER

颗粒物质是大量离散的固体颗粒相互作用而组成的复杂体系.依据颗粒排布的稀疏程度,体系可分为颗粒气体、颗粒流体和颗粒固体,它们有不同本质的动量传递和能量耗散机制.后两者属于密集颗粒物质体系,内部形成了颗粒→力链→体系的多尺度结构,并涉及多个特征时间尺度,是典型的多尺度体系.合理分割体系结构层次、正确理解不同层次的物理过程、并确定它们之间的关联是密集颗粒物质研究的核心任务.本文依次分析了密集颗粒物质的内在物理图像、多尺度结构层次和特征时间等,并介绍了多尺度研究框架.

The granular matter is a large assemblage of dense packing particles.The interparticle forces are usually dominant in comparison with drag forces from interstitial fluid,and are transmitted through heterogeneous force chains.This paper studies the multiscale structures and rate-dependent processes involved in granular materials,and shows that the granular matter is a typical multiscale mechanical system.Three length scales are identified,particle,force chain and granular system in micro- meso- and marco scales,respectively, and with three related characteristic time scales.The correlation of particle-force chain,force chain-system would be the major problem in the multiscale analysis of granular materials.