The Influence of Crack-Face Normal and Shear Stress Loading on Hydraulic Fracture-Tip Singular Plastic Fields
| Autor: | Papanastasiou, Panos C., Durban, D. |
|---|---|
| Přispěvatelé: | Papanastasiou, Panos C. [0000-0002-7506-221X] |
| Rok vydání: | 2018 |
| Předmět: |
Displacement profiles
Cracks Material parameter Materials science Stress analysis Loaded cracks Shear tractions 02 engineering and technology Power law Shear traction Shear flow Drucker–Prager Drucker–Prager yield criterion Singularity 0203 mechanical engineering Shear stress von Mises yield criterion Crack tips Civil and Structural Engineering Crack propagation Normal and shear stress von Mises Geology Mechanics Hydraulic fracturing 021001 nanoscience & nanotechnology Geotechnical Engineering and Engineering Geology Crack tip Singular plastic fields Boundary layer Fracture 020303 mechanical engineering & transports Shear (geology) Singular stress field Hardening Representative case Hardening (metallurgy) Boundary layers 0210 nano-technology Hydrogen embrittlement |
| Zdroj: | Rock Mechanics and Rock Engineering |
| ISSN: | 1434-453X 0723-2632 |
| DOI: | 10.1007/s00603-018-1437-x |
| Popis: | We investigated the singular plastic fields at the crack tip of a fracture that is loaded with normal and shear loads due to a viscous flow in a hydraulic fracturing. The level of the expected shear load in comparison with the normal load is examined. The lubrication flow and plastic deformation were decoupled assuming that the relation between applied shear load and normal load follows a linear friction-type relation. This assumption allows to investigate extreme bounds of the solution. Both the applied normal and shear loads are assumed to exhibit singular behavior near the tip which is consistent at the fracture surfaces with the plastic singular stress fields that are investigated. The fractured material is assumed to obey a non-associative Drucker–Prager solid with power law hardening response. The singular values and the corresponding fields were determined over a range of material parameters. For both von Mises material and associative Drucker–Prager material, we found that the level of singularity is given by 1/n where n is the power coefficient of the hardening relation. This level of singularity is stronger than the HRR value, 1/(n + 1), which has been determined for traction free crack surfaces. We found that the shear loading does not influence the level of singularity but it changes the shape of the developed plastic zones with the emergence of a boundary layer near the fracture surface. Deviation from material associativity produces consistent small increases in the level of singularity. The near-tip stress, strain and displacement profiles are illustrated for a few representative cases. © 2018 Springer-Verlag GmbH Austria, part of Springer Nature 1 13 |
| Databáze: | OpenAIRE |
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