Details
| Original language | English |
|---|---|
| Article number | 115084 |
| Journal | Computer Methods in Applied Mechanics and Engineering |
| Volume | 396 |
| Early online date | 21 May 2022 |
| Publication status | Published - 1 Jun 2022 |
Abstract
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.
Keywords
- Hydraulic fracture, Micromechanics, Non-associative plasticity, Phase-field models, Porous media, Variational formulation
ASJC Scopus subject areas
- Engineering(all)
- Computational Mechanics
- Engineering(all)
- Mechanics of Materials
- Engineering(all)
- Mechanical Engineering
- Physics and Astronomy(all)
- General Physics and Astronomy
- Computer Science(all)
- Computer Science Applications
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In: Computer Methods in Applied Mechanics and Engineering, Vol. 396, 115084, 01.06.2022.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Variational modeling of hydromechanical fracture in saturated porous media
T2 - A micromechanics-based phase-field approach
AU - Ulloa, Jacinto
AU - Noii, Nima
AU - Alessi, Roberto
AU - Aldakheel, Fadi
AU - Degrande, Geert
AU - François, Stijn
N1 - Funding Information: F. Aldakheel and N. Noii were funded by the Priority Program DFG-SPP 2020 (project number: 353757395).
PY - 2022/6/1
Y1 - 2022/6/1
N2 - 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.
AB - 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.
KW - Hydraulic fracture
KW - Micromechanics
KW - Non-associative plasticity
KW - Phase-field models
KW - Porous media
KW - Variational formulation
UR - http://www.scopus.com/inward/record.url?scp=85133895493&partnerID=8YFLogxK
U2 - 10.1016/j.cma.2022.115084
DO - 10.1016/j.cma.2022.115084
M3 - Article
AN - SCOPUS:85133895493
VL - 396
JO - Computer Methods in Applied Mechanics and Engineering
JF - Computer Methods in Applied Mechanics and Engineering
SN - 0045-7825
M1 - 115084
ER -