A both two- and three-dimensional grain-based hybrid finite-discrete element method (HFDEM-GB2D/3D) is developed and parallelized on the basis of the general-purpose graphic-processing-units. It is then calibrated by modelling the failure process of heterogeneous rocks in uniaxial compression tests. After that, it is applied to investigate the dynamic fracture process of heterogeneous rocks in triaxial Hopkinson bar tests. It is concluded that HFDEM-GB2D/3D can consider the actual microstructures of heterogeneous rocks to investigate the intra-, trans- and inter-granular crack propagations besides modelling the failure process of heterogeneous rocks.
Heterogeneity is a material fabric characteristic that should be better understood in terms of its role in influencing the fracture progression process. In recent years, the grain-scale heterogeneities of rocks have been characterized using various methods, including statistical methods such as Weibull's distribution and grain-based methods. It is generally agreed (Yahaghi et al., 2023) that grain-based methods can better characterize some microstructure properties of rocks and address their effects on the macroscopic behaviors, bulk properties and failure processes of rocks, although grain-based methods are much more time-consuming than statistical methods. However, rock microstructures are complex and include more properties than those considered in the currently available grain-based methods, such as the grain morphology, grain size and spatial distribution, crystallographic anisotropy and orientation, elastic properties and interface properties. Thus, it is of fundamental importance to incorporate more if not all important microstructure properties of rocks when investigating the macroscopic responses (e.g., a complete stress–strain curve), localized microscopic cracking nucleation, coalescence and propagation, the entire failure processes of these rocks and their sensitivities to the presence of bedding planes, flaws, pores, and cavities inherent in the rocks. This paper aims to propose both a two- and three-dimensional grain-based hybrid finite-discrete element method (HFDEM-GB2D/3D) parallelized based on general-purpose graphic-processing-unit for investigating the inter-, intra- and trans-granular failures of heterogeneous rocks under static and dynamic loads.
