期刊
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
卷 396, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cma.2022.115084
关键词
Phase-field models; Micromechanics; Hydraulic fracture; Porous media; Variational formulation; Non-associative plasticity
资金
- Priority Program DFG-SPP 2020 [353757395]
This paper presents a novel variational phase-field model to describe fracture processes in saturated porous media. The model utilizes a micromechanics-based theory to connect field variables with physical mechanisms at the microcrack level, where damage and plasticity arise from microcrack growth and frictional sliding. The model also considers hydromechanical coupling effects and incorporates a non-associative frictional plasticity law.
This paper presents a novel variational phase-field model for different fracture processes in fully saturated porous media. As a key feature, the model employs a micromechanics-based theory for the description of brittle-tensile and compressive- ductile fracture. As such, the field variables are linked to physical mechanisms at the microcrack level, with damage emerging as the consequence of microcrack growth Similarly, plasticity emerges as a consequence of the frictional sliding of closed microcracks. In this way, the evolution of opening microcracks in tension leads to (mode I) brittle fracture, while the evolution of closed microcracks in compression/shear leads to (mode II) ductile fracture. These failure mechanisms are coupled to fluid flow, resulting in a Darcy-Biot-type hydromechanical model. Therein, in the tensile regime, plasticity naturally vanishes, while damage is driven by poroelastic energy, accounting for the pressure in fluid-filled opening microcracks. On the other hand, in the compressive/shear regime, the plastic driving force naturally follows as a Terzaghi-type effective stress in terms of the local stress field acting on the microcrack surfaces, while damage is solely driven by the frictionally blocked free energy. As another important feature, the model includes a non-associative frictional plasticity law. Nevertheless, a thermodynamically consistent variational framework is employed, for which different energetic principles are discussed. Finally, the numerical simulations show that the model captures relevant hydromechanical coupling effects in benchmark problems, including mechanically induced shear fracture and hydraulically induced tensile fracture. (C) 2022 Elsevier B. V. All rights reserved.
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