应用离散单元法研究散体微观结构

针对散体材料复杂的微观作用机制,采用离散单元法,研究了重力场内由两种粒径球体组成的微观混合结构,分析了各种类型配位数的大小及分布。结果表明,单一接触类型的配位数及分量配位数分布与体积组成有关。具体表现为:随着小粒径粒子体积百分比的增加,小粒子间、大粒子与小粒子间的配位数增大,而小粒子与大粒子间、大粒子间的配位数则减小;小、大粒径分量平均配位数均增大,且大粒径分量配位数增长更快。然而,两种粒径散粒体重力堆积下的全平均配位数与空隙率及体积组成无关,基本保持为定值。

Analyses of Micro-structure of Granular Materials Using Discrete Element Method

Micro-mechanism of granular materials is complicated for the discrete behaviour.Numerical method of DEM is applied to the study of micro-structure of binary packing of spherical particles in terms of size and distribution of coordination number under the influence of gravity force.Results show that the volume fraction influences the distributions of coordination number of single contact type and individual components.It features that increasing the volume fraction of small component increases the small-tosmall and large-to-small contacts and decreases the small-to-large and large-to-large contacts.The mean coordination number of small and large component both increase with the increase of the volume fraction of small component,and the trend is more apparent for large component.However,the overall mean coordination number is essentially a constant and independent of porosity or volume fraction for the binary packing under gravity.