Abstract

In this article, the response of an interfacial layer developed along a particulate–continuum interface is explored under two opposite normal confining constraints. To this end, a cohesionless granular strip subjected to both isochoric and non-isochoric conditions is monotonously sheared against an adjacent wall of different surface roughness values. Numerical simulations are performed using a finite element method formulated within an elasto-plastic polar continuum, equipped by granular rotation, couple stress, and average grain size. Along the wall in motion, the slide and rotation resistance of the first layer of boundary grains are innovatively determined by the additional polar boundary conditions, taking into account a ratio between slip and granular rotation along the wall, asperities of wall surface, and grain size. In particular, the combined interaction of material dilatancy constraint and wall roughness are examined on the frictional resistance and deformation of the interfacial layer. It is shown that the normal confinement and the roughness geometry of the wall surface have visible impacts on the stress-displacement response of the interfacial layer. The evolution of stresses and couple stresses is entirely different in isochoric and non-isochoric conditions. However, the stationary value of the interfacial strength is independent of how the bounding wall confines the granular body. Besides, the deformations manifested out of the interfacial layer are more pronounced in isochoric shearing than non-isochoric shearing. Nevertheless, the location and progression of the interfacial layer do not necessarily depend on the applied confining constraint after large shearing.

摘要

在这篇文章中，在两个相反的法向限制条件下探索了沿颗粒-连续介质界面形成的界面层的响应。为此，经受等容和非等容条件的无粘性颗粒条被单调剪切到具有不同表面粗糙度值的相邻壁上。使用在弹塑性极连续体中制定的有限元方法进行数值模拟，配备颗粒旋转、耦合应力和平均晶粒尺寸。沿着运动的壁面，第一层边界晶粒的滑动和旋转阻力创新性地由附加的极边界条件决定，考虑了沿着壁面的滑动和颗粒旋转之间的比率、壁面的粗糙度和晶粒尺寸. 尤其，研究了材料剪胀约束和壁面粗糙度的联合相互作用对界面层摩擦阻力和变形的影响。结果表明，壁面的法线约束和粗糙度几何形状对界面层的应力-位移响应具有明显的影响。在等容和非等容条件下，应力和耦合应力的演变完全不同。然而，界面强度的固定值与边界壁如何限制颗粒体无关。此外，界面层外的变形在等容剪切中比非等容剪切更明显。然而，界面层的位置和进展不一定取决于大剪切后施加的限制约束。