Particles slide and roll on each other when a granular medium is sheared. Consequently, the tribological properties, such as inter-particle friction and adhesion, play a major role in influencing their bulk failure and rheology. Although the influence of roughness on adhesion and friction of contacting surfaces is known, the incorporation of the surface roughness in the numerical modelling of granular materials has received little attention. In this study, the boundary element method (BEM), which is widely used for simulating the mechanics of interacting surfaces, is coupled with discrete element method (DEM) and the bulk deformation of granular materials is analysed. A BEM code, developed in-house, is employed to calculate the normal force–displacement behaviour for rough contact deformations, based on which a contact model is proposed. This is an efficient and relatively fast method of calculating the contact mechanics of rough surfaces. The resulting model is then implemented in the simulations by DEM to determine the effect of micro-scale surface roughness on the bulk compression of granular materials. This study highlights the importance of the effect of surface characteristics on contact behaviour of particles for the case of shallow footing and provides an efficient approach for modelling the flow behaviour of a large number of rough particles.

中文翻译：

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耦合边界元法和离散元法对颗粒粗糙度对整体变形的影响

当剪切颗粒状介质时，颗粒彼此滑动。因此，摩擦特性，例如颗粒间的摩擦和附着力，在影响其整体破坏和流变性方面起着重要作用。尽管粗糙度对接触表面的附着力和摩擦的影响是已知的，但是在颗粒材料的数值模型中将表面粗糙度并入的过程却很少受到关注。在这项研究中，边界元法（BEM）被广泛地用于模拟相互作用表面的力学，并与离散元法（DEM）相结合，并分析了颗粒材料的整体变形。内部开发的BEM代码用于计算粗糙接触变形的法向力-位移行为，并在此基础上提出了接触模型。这是计算粗糙表面接触力学的有效且相对较快的方法。然后，通过DEM在仿真中实施生成的模型，以确定微尺度表面粗糙度对粒状材料整体压缩的影响。这项研究突出了浅基础情况下表面特性对颗粒接触行为的影响的重要性，并提供了一种对大量粗糙颗粒的流动行为进行建模的有效方法。