›› 2018, Vol. 39 ›› Issue (9): 3440-3452.doi: 10.16285/j.rsm.2017.2110

• 数值分析 • 上一篇    下一篇

基于改进粗糙表面Greenwood-William 接触模型的离散元方法

赵婷婷1,冯云田1,王 敏1,王 勇2   

  1. 1. 斯旺西大学 辛克维奇计算工程中心,斯旺西 英国; 2. 中国科学院武汉岩土力学研究所 岩土力学与工程国家重点实验室,湖北 武汉 430071
  • 收稿日期:2017-10-20 出版日期:2018-09-11 发布日期:2018-10-08
  • 通讯作者: 冯云田,男,1963年生,博士,教授,主要从事计算力学的教学与研究工作。E-mail: y.feng@swansea.ac.uk E-mail: 842758@swansea.ac.uk
  • 作者简介:赵婷婷,女,1989年生,博士研究生,主要从事离散元方法的研究工作。
  • 基金资助:

    国家自然科学基金(No.51579237)

Modified Greenwood-Williamson model based stochastic discrete element method for contact with surface roughness

ZHAO Ting-ting1, FENG Yun-tian1, WANG Ming1, WANG Yong2   

  1. 1. Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea, United Kingdom; 2. Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, China Academy of Science, Wuhan, Hubei 430071, China
  • Received:2017-10-20 Online:2018-09-11 Published:2018-10-08
  • Supported by:

    This work was supported the National Science Foundation of China(51579237).

摘要: 颗粒材料的表面粗糙度在很大程度上影响颗粒集合体的力学特性,传统离散元方法中对颗粒具有光滑表面的假设,使得其无法准确描述真实颗粒材料的接触行为,因此有必要发展可以定量考虑颗粒表面粗糙度的随机离散元方法。在介绍经典粗糙表面接触模型Greenwood-Williamson(简称G-W)模型的基础上,分析了G-W模型应用于离散元模拟的缺陷,提出了分别考虑颗粒重叠光滑部分和粗糙部分的改进模型,并推导出了相应的无量纲形式,对比了经典G-W模型与改进模型计算得到的粗糙颗粒接触时压力分布、变形分布、总接触力等结果。结果表明,改进的接触模型能够更直观地反映颗粒表面粗糙度对颗粒接触的影响。基于改进的接触模型,采用两步曲线拟合手段,得到了可以直接应用于离散元模拟的随机法向接触定律。将该定律通过开发用户自定义接触模型引入到颗粒离散元程序PFC3D中。通过数值试验观察了表面粗糙度在不同加载路径下对颗粒集合体力学特性的影响。

关键词: 表面粗糙度, Greenwood-Williamson模型, 接触定律, 随机离散元

Abstract: The surface roughness of particles may have a strong influence on the mechanical properties of granular assemblies. The assumption made in the classic discrete element method(DEM) that the particle surface is smooth makes it difficult to describe the contact behavior of real granular materials accurately. It is necessary therefore to develop the stochastic discrete element method (SDEM) which could quantitatively consider the surface roughness of particles. To this end, the most popular statistical treatment of rough surface—the Greenwood-Williamson(G-W) model is introduced. Then the defects of incorporating the G-W model into DEM simulation are fully addressed. An extended model which treats the rough surface as the combination of two parts is proposed and the corresponding non-dimensional form for subsequent DEM simulations is presented. The pressure distribution, deformation distribution and total contact force obtained by the G-W model and the extended version are compared. It shows that the extended model can better reflect the influence of the surface roughness on contact between rough particles. Based on the extended model, a new normal interaction law ready to be incorporated into DEM is derived by the curve-fitted empirical formula. A user defined contact model of the new normal interaction law is incorporated into (the particle flow code)PFC3D. Numerical simulations are first conducted to compare the influence of the surface roughness on mechanical properties of particulate system under different loading conditions.

Key words: surface roughness, Greenwood-Williamson model, contact law, stochastic discrete element method

中图分类号: 

  • TV 311

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