Effect of size polydispersity on the structural and vibrational characteristics of two-dimensional granular assemblies  

作　　者：张国华 孙其诚 石志萍 冯旭 顾强 金峰 

机构地区：[1]Department of Physics,University of Science and Technology Beijing [2]State Key Laboratory for Hydroscience and Engineering,Tsinghua University

出　　处：《Chinese Physics B》2014年第7期589-595,共7页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11272048,51239006,and 11034010);the European Commission MarieCurie Actions(Grant No.IRSES-294976);the National Basic Research Program of China(Grant No.2010CB731504)

摘　　要：Two-dimensional disordered granular assemblies composed of 2048 polydispersed frictionless disks are simulated using the discrete element method. The height of the first peak of the pair correlation function, gl, the local and global bond orientational parameters ψ6^1 and ψ6^g, and the fluctuations of these parameters decrease with increasing polydispersity s, implying the transition from a polycrystalline state to an amorphous state in the system. As s increases, the peak position of the boson peak aJBp shifts towards a lower frequency and the intensity of the boson peak D（ωBP）/ωBp increases, indicating that the position and the strength of the boson peak are controlled by the polydispersity of the system. Moreover, the inverse of the boson peak intensity ωBP/D（ωBP）, the shear modulus G, and the basin curvature SIS all have a similar dependence on s, implying that the s dependence of the vibrational density of states at low frequencies likely originates from the s dependence of the basin curvature.Two-dimensional disordered granular assemblies composed of 2048 polydispersed frictionless disks are simulated using the discrete element method. The height of the first peak of the pair correlation function, gl, the local and global bond orientational parameters ψ6^1 and ψ6^g, and the fluctuations of these parameters decrease with increasing polydispersity s, implying the transition from a polycrystalline state to an amorphous state in the system. As s increases, the peak position of the boson peak aJBp shifts towards a lower frequency and the intensity of the boson peak D（ωBP）/ωBp increases, indicating that the position and the strength of the boson peak are controlled by the polydispersity of the system. Moreover, the inverse of the boson peak intensity ωBP/D（ωBP）, the shear modulus G, and the basin curvature SIS all have a similar dependence on s, implying that the s dependence of the vibrational density of states at low frequencies likely originates from the s dependence of the basin curvature.

关 键 词：granular matter vibrational characteristics size polydispersity structural characteristics 

分 类 号：O572.2[理学—粒子物理与原子核物理]