圆盘体系在各向同性压缩下的接触结构及晶格化  

Contact Structure of Disk Systems and Its Crystallization under Isotropic Compression

作　　者：戴丹 张兴刚 DAI Dan;ZHANG Xing-gang(College of Computer Science and Technology,Guizhou University,Guiyang 550025,China;College of Science,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学计算机科学与技术学院,贵阳550025 [2]贵州大学物理学院,贵阳550025

出　　处：《科学技术与工程》2024年第11期4389-4396,共8页Science Technology and Engineering

基　　金：贵州省科技计划(ZK2022148);国家自然科学基金(11965007);贵州大学实验室开放项目(SYSKF2023-049)。

摘　　要：结合离散元模拟及接触网络的统计分析对双分散圆盘体系在各向同性压缩下的接触结构及其晶格化进行研究。离散元模拟中通过改变大小颗粒的粒径比控制分散程度,使得体系成为单分散或者近似单分散的体系。用接触类型的百分比描述接触结构的统计特征。给出了体系的压强以及各种接触类型的百分比随堆积分数变化的曲线,研究了摩擦与粒径比对这些曲线的影响,并且着重讨论了摩擦和单分散程度对晶格结构的影响。模拟结果表明,随着圆盘数的增多,临界体积分数逐渐增大;随着摩擦系数与粒径比的增大,临界体积分数逐渐减小。摩擦与单分散程度是影响接触结构晶格化的主要因素。对于单分散体系,当摩擦系数较小时,体系在持续的压缩过程中容易形成三角晶格团簇;随着摩擦系数的增大,体系晶格化程度减小;当摩擦系数大于0.8以后,很难形成三角晶格团簇。对于近似单分散的体系,只有单分散程度很高时,压缩过程的持续才会导致明显的晶格化;随着粒径比的增大,晶格结构难以出现,体系通常形成无序堆积。The discrete element method and statistical analysis of contact networks were combined to study the packing structure and it's crystallization for disk systems under isotropic compression.In the discrete element simulation,the dispersion degree was controlled by changing the particle size ratio of large and small particles to make the system become monodisperse or approximate monodisperse.The percentage of contact types was used to describe the statistical characteristics of contact structure.The curves of the pressure of the system and the percentage of various contact types varying with the packing fraction were given,the influence of friction and particle size ratio on these curves was studied,and the effects of friction and monodisperse degree on the crystal lattice structure were emphatically discussed.The simulation results show that with the increase of the number of disks,the critical packing fraction increases gradually,with the increase of friction and particle size ratio,the critical packing fraction decreases gradually.Friction and the level of monodispersity are the main factors affecting the extent of crystallization of contact structure.In the monodisperse disk system,when the friction coefficient is small,triangular lattice clusters are easily formed in the continuous compression process of the system,with the increase of friction coefficient,the extent of crystallization decreases.When the friction coefficient is greater than 0.8,it is difficult to form triangular lattice clusters.In the approximate monodisperse disk system,only when the level of monodispersity is very high,the continuous compression process will lead to obvious crystallization.With the increase of particle radius ratio,the crystal lattice structure is more difficult to appear,and the system usually forms disordered packing.

关 键 词：颗粒体系 离散元模拟 接触网络 晶格结构 堆积分数 

分 类 号：O414.2[理学—理论物理]