In this work, we present a newly developed workflow to study the combined effect of shear and normal stresses upon a preexisting fracture plane. This workflow is used to study the behavior of both single grain and polycrystalline materials, with varying material properties. The surface roughness and aperture of preexisting fractures are highly dependent upon the dynamic stress behavior within rock formations. Due to shear slippage, or variation in normal stress, a preexisting fracture may become more or less conductive, leading to changes in effective porosity, where such changes are caused by purely elastic deformation, plastic deformation, material failure, or a combination thereof. The numerical modeling framework demonstrated herein is based upon the meshless material point method (MPM). In using MPM, the workflow can capture large deformations due to applied shear and normal stresses. Additionally, no special geometric treatment is required at the point of contact between fracture surfaces. Models involving purely elastic, single-grain materials, as well as more complex, plastic, polycrystalline bodies, are presented, highlighting the flexibility of the proposed approach.

在这项工作中，我们提出了一个新开发的工作流程，以研究剪切力和法向应力对预先存在的断裂平面的综合影响。该工作流程用于研究具有不同材料特性的单晶粒和多晶材料的行为。既有裂缝的表面粗糙度和孔径高度取决于岩层内的动态应力行为。由于剪切滑移或法向应力的变化，先前存在的裂缝可能或多或少具有导电性，从而导致有效孔隙率发生变化，而这种变化是由纯粹的弹性变形，塑性变形，材料破坏或它们的组合引起的。本文演示的数值建模框架基于无网格材料点方法（MPM）。在使用MPM时，由于施加的剪切力和法向应力，工作流可以捕获较大的变形。另外，在断裂表面之间的接触点不需要特殊的几何处理。提出了涉及纯弹性单晶粒材料以及更复杂的塑料多晶体的模型，突出了该方法的灵活性。