当前位置: X-MOL 学术Comp. Part. Mech. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
DEM simulations of polydisperse media: efficient contact detection applied to investigate the quasi-static limit
Computational Particle Mechanics ( IF 3.3 ) Pub Date : 2020-09-21 , DOI: 10.1007/s40571-020-00361-2
Tom Shire , Kevin J. Hanley , Kevin Stratford

Discrete element modeling (DEM) of polydisperse granular materials is significantly more computationally expensive than modeling of monodisperse materials as a larger number of particles are required to obtain a representative elementary volume, and standard contact detection algorithms become progressively less efficient with polydispersity. This paper presents modified contact detection and inter-processor communication schemes implemented in LAMMPS which account for particles of different sizes separately, greatly improving efficiency. This new scheme is applied to the inertial number (I), which quantifies the ratio of inertial to confining forces. This has been used to identify the quasi-static limit for shearing of granular materials, which is often taken to be \( I = 10^{ - 3} \). However, the expression for the inertial number contains a particle diameter term and therefore it is unclear how to apply this for polydisperse media. Results of DEM shearing tests on polydisperse granular media are presented in order to determine whether \( I \) provides a unique quasi-static limit regardless of polydispersity and which particle diameter term should be used to calculate \( I \). The results show that the commonly used value of \( I = 10^{ - 3} \) can successfully locate the quasi-static limit for monodisperse media but not for polydisperse media, for which significant variations of macroscopic stress ratio and microscopic force and contact networks are apparent down to at least \( I = 10^{ - 6} \). The quasi-static limit could not be conclusively determined for the polydisperse samples. Based on these results, the quasi-staticity of polydisperse samples should not be inferred from a low inertial number as currently formulated, irrespective of the particle diameter used in its calculation.



中文翻译:

多分散介质的DEM模拟:有效的接触检测用于研究准静态极限

多分散颗粒材料的离散元素建模(DEM)比单分散材料的建模要昂贵得多,因为需要大量的粒子才能获得具有代表性的基本体积,并且标准的接触检测算法在多分散性方面的效率逐渐降低。本文提出了在LAMMPS中实现的改进的接触检测和处理器间通信方案,该方案分别考虑了不同大小的粒子,从而大大提高了效率。将该新方案应用于惯性数(I),以量化惯性与约束力之比。这已被用来确定颗粒材料剪切的准静态极限,通常被认为是\(I = 10 ^ {-3} \)。但是,惯性数的表达式包含粒径项,因此尚不清楚如何将其应用于多分散介质。给出了在多分散颗粒介质上进行DEM剪切测试的结果,以确定\(I \)是否提供唯一的准静态极限,而与多分散性无关,并且应使用哪个粒径术语来计算\(I \)。结果表明,常用的\(I = 10 ^ {-3} \)值可以成功地定位单分散介质的准静态极限,而不能定位多分散介质的准静态极限,为此,宏观应力比和微观力以及接触网络至少可以达到\(I = 10 ^ {-6} \)。无法确定多分散样品的准静态极限。根据这些结果,不应从当前制定的低惯性数推断多分散样品的准静态性,而与计算中使用的粒径无关。

更新日期:2020-09-22
down
wechat
bug