Numerical study on thermo-hydro-mechanical coupling phenomena in saturation and unsaturated ground

2014 ◽  
pp. 1415-1420
Author(s):  
Y Xiong ◽  
F Zhang ◽  
Y Li
Keyword(s):  
Numerical Study ◽  
Mechanical Coupling ◽  
Coupling Phenomena

scholarly journals Numerical Study on Damage Zones Induced by Excavation and Ventilation in a High-Temperature Tunnel at Depth

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4773
Author(s):  
Jianyu Li ◽  
Hong Li ◽  
Zheming Zhu ◽  
Ye Tao ◽  
Chun’an Tang
Keyword(s):  
High Temperature ◽  
Lateral Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Fracture Morphology ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Geothermal System ◽  
Mechanical Coupling ◽  
Lateral Pressure Coefficient

Geothermal power is being regarded as depending on techniques derived from hydrocarbon production in worldwide current strategy. However, it has artificially been developed far less than its natural potentials due to technical restrictions. This paper introduces the Enhanced Geothermal System based on Excavation (EGS-E), which is an innovative scheme of geothermal energy extraction. Then, based on cohesion-weakening-friction-strengthening model (CWFS) and literature investigation of granite test at high temperature, the initiation, propagation of excavation damaged zones (EDZs) under unloading and the EDZs scale in EGS-E closed to hydrostatic pressure state is studied. Finally, we have a discussion about the further evolution of surrounding rock stress and EDZs during ventilation is studied by thermal-mechanical coupling. The results show that the influence of high temperature damage on the mechanical parameters of granite should be considered; Lateral pressure coefficient affects the fracture morphology and scale of tunnel surrounding rock, and EDZs area is larger when the lateral pressure coefficient is 1.0 or 1.2; Ventilation of high temperature and high in-situ stress tunnel have a significant effect on the EDZs scale; Additional tensile stress is generated in the shallow of tunnel surrounding rock, and the compressive stress concentration transfers to the deep. EDZs experiences three expansion stages of slow, rapid and deceleration with cooling time, and the thermal insulation layer prolongs the slow growth stage.

scholarly journals On Hydromechanical Interaction during Propagation of Localized Damage in Rocks

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 162
Author(s):  
A.A. Jameei ◽  
S. Pietruszczak
Keyword(s):  
Numerical Study ◽  
Fluid Pressure ◽  
Implicit Time ◽  
Integration Scheme ◽  
Internal Length ◽  
Element Analysis ◽  
Equivalent Permeability ◽  
Mechanical Coupling ◽  
Splitting Test ◽  
Localized Damage

This paper provides a mathematical description of hydromechanical coupling associated with propagation of localized damage. The framework incorporates an embedded discontinuity approach and addresses the assessment of both hydraulic and mechanical properties in the region intercepted by a fracture. Within this approach, an internal length scale parameter is explicitly employed in the definition of equivalent permeability as well as the tangential stiffness operators. The effect of the progressive evolution of damage on the hydro-mechanical coupling is examined and an evolution law is derived governing the variation of equivalent permeability with the continuing deformation. The framework is verified by a numerical study involving 3D simulation of an axial splitting test carried out on a saturated sample under displacement and fluid pressure-controlled conditions. The finite element analysis incorporates the Polynomial-Pressure-Projection (PPP) stabilization technique and a fully implicit time integration scheme.

scholarly journals Evolution of the East Antarctic Ice Sheet: A Numerical Study of Thermo-Mechanical Response Patterns With Changing Climate

1988 ◽  
Vol 11 ◽  
pp. 52-59 ◽  
Author(s):  
P. Huybrechts ◽  
J. Oerlemans
Keyword(s):  
Mechanical Response ◽  
Flow Line ◽  
Numerical Study ◽  
Ice Core ◽  
Ice Sheet ◽  
Antarctic Ice Sheet ◽  
Mechanical Coupling ◽  
Vostok Station ◽  
Basal Melting ◽  
East Antarctic Ice Sheet

An efficient numerical ice-sheet model, including time dependence and full thermo-mechanical coupling, has been developed in order to investigate the thermal regime and overall configuration of a polar ice sheet with respect to changing environmental conditions. From basic sensitivity experiments, in which a schematic East Antarctic ice sheet is forced with a typical glacial–interglacial climatic shift, it is found that: (i) the mutual interaction of temperature and deformation has a stabilizing effect on its steady-state configuration; (ii) in the transient mode, this climatic transition initially leads to increased ice thickness due to enhanced accumulation, after which this trend is reversed due to a warmer base. Time-scales for this reversal are of the order of 103 years in marginal zones and of 104 years in interior regions; (iii) horizontal heat advection plays a major role in damping possible runaway behaviour due to the dissipation – strain-rate feed-back, suggesting that creep instability is a rather unlikely candidate to initiate surging of the East Antarctic ice sheet. The model is then applied to four East Antarctic flow lines. Only the flow line passing through Wilkes Land appears to be vulnerable to widespread basal melting, due to enhanced basal warming following climatic warming. Time-dependent modelling of the Vostok flow line indicates that the Vostok Station area has risen about 95 m since the beginning of the present interglacial due to thermo-mechanical effects, which is of particular interest in interpreting the palaeoclimatic signal of the ice core obtained there.

Numerical Study on Bending Behavior of Copper Alloy Thin Plate by Single Pulse Laser

2014 ◽  
Vol 1003 ◽  
pp. 113-116
Author(s):  
Su Qin Jiang ◽  
Ai Hui Liu ◽  
Xue Ting Wang ◽  
Jian Hua Wu ◽  
Bo Kui Li
Keyword(s):  
Thin Plate ◽  
Pulse Laser ◽  
Copper Alloy ◽  
Numerical Study ◽  
Dynamic Change ◽  
Single Pulse ◽  
Coupling Model ◽  
Laser Forming ◽  
Bottom Surface ◽  
Mechanical Coupling

To study the bending characteristics of copper alloy thin plate by single pulse laser, the thermal mechanical coupling model of pulsed laser forming (PLF) was established; the dynamic change and steady distribution for the fields of temperature, stress& strain and displacement were analyzed. The results show n that during the pulse laser heating stage, the temperature gradient along the thickness direction is far less than that of the heat affected zone; due to the constraints of materials around the heating field, the compressive stress and negative strain are appeared, the cantilever end of sample produces warping deformations; in the cooling stage, the temperature of top and bottom surface material drops rapidly, the sample is with a negative bending and reduced deformation. This is related to the transferring of the stress change and the recovery of part of the elastic deformation in heating area.

scholarly journals Experimental and Numerical Study of the Interfacial Shear Strength in Carbon Fiber/Epoxy Resin Composite under Thermal Loads

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Hongxiao Wang ◽  
Xiaohui Zhang ◽  
Yugang Duan ◽  
Lingjie Meng
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Interfacial Shear Strength ◽  
Numerical Study ◽  
Resin Composite ◽  
Interfacial Shear ◽  
Thermal Loads ◽  
Mechanical Coupling ◽  
Pull Out

This study examined the influence mechanism of temperature on the interfacial shear strength (IFSS) between carbon fiber (CF) and epoxy resin (EP) matrices under various thermal loads using experimental and numerical simulation methods. To evaluate the change in IFSS as a function of the increase in temperature, a microbond test was performed under controlled temperature environment from 23°C to 150°C. The experimental results showed that IFSS values of CF/EP reduce significantly when the temperature reaches near glass transition temperature. To interpret the effect of thermal loads on IFSS, a thermal-mechanical coupling finite element model was used to simulate the process of fiber pull-out from EP. The results revealed that temperature dependence of IFSS is linked to modulus of the matrix as well as to the coefficients of thermal expansion of the fiber and matrix.

scholarly journals Evolution of the East Antarctic Ice Sheet: A Numerical Study of Thermo-Mechanical Response Patterns With Changing Climate

1988 ◽  
Vol 11 ◽  
pp. 52-59 ◽  
Author(s):  
P. Huybrechts ◽  
J. Oerlemans
Keyword(s):  
Mechanical Response ◽  
Flow Line ◽  
Numerical Study ◽  
Ice Core ◽  
Ice Sheet ◽  
Antarctic Ice Sheet ◽  
Mechanical Coupling ◽  
Vostok Station ◽  
Basal Melting ◽  
East Antarctic Ice Sheet

An efficient numerical ice-sheet model, including time dependence and full thermo-mechanical coupling, has been developed in order to investigate the thermal regime and overall configuration of a polar ice sheet with respect to changing environmental conditions.From basic sensitivity experiments, in which a schematic East Antarctic ice sheet is forced with a typical glacial–interglacial climatic shift, it is found that: (i) the mutual interaction of temperature and deformation has a stabilizing effect on its steady-state configuration; (ii) in the transient mode, this climatic transition initially leads to increased ice thickness due to enhanced accumulation, after which this trend is reversed due to a warmer base. Time-scales for this reversal are of the order of 103 years in marginal zones and of 104 years in interior regions; (iii) horizontal heat advection plays a major role in damping possible runaway behaviour due to the dissipation – strain-rate feed-back, suggesting that creep instability is a rather unlikely candidate to initiate surging of the East Antarctic ice sheet.The model is then applied to four East Antarctic flow lines. Only the flow line passing through Wilkes Land appears to be vulnerable to widespread basal melting, due to enhanced basal warming following climatic warming. Time-dependent modelling of the Vostok flow line indicates that the Vostok Station area has risen about 95 m since the beginning of the present interglacial due to thermo-mechanical effects, which is of particular interest in interpreting the palaeoclimatic signal of the ice core obtained there.

scholarly journals Numerical study of TRIP transformation in 35NCD16 steel-effects of plate orientation and some criteria

2021 ◽  
Vol 16 (59) ◽  
pp. 444-460
Author(s):  
Mounir Gaci ◽  
Fedaoui Kamel ◽  
Lazhar Baroura ◽  
Amar Talhi
Keyword(s):  
Grain Boundary ◽  
Shear Deformation ◽  
Numerical Study ◽  
Elastic Behavior ◽  
The Finite Element Method ◽  
Elastoplastic Behavior ◽  
Mechanical Coupling ◽  
First Case ◽  
Martensitic Plate ◽  
The Impact

This study aims to analyze the effect of thermo mechanical coupling damage in the presence of a phase change (austenite/martensite) in 35NCD16 steel. The impact of increasing mechanical traction load, accompanied by a martensitic transformation on the scale of a single grain with boundary has been studied. The prediction transformation of induced plasticity (TRIP) was evaluated by taking into account the following parameters: twenty shear directions of the martensitic plates, two values of the shear deformation of the martensitic plates, energetic and thermodynamics criteria for getting in order the transformation of the martensitic plates, elastoplastic behavior of the two areas in the first case (martensitic plate and grain boundary) and elastic behavior for the grain boundary in the second case. The numerical calculation is carried out using the finite element method (FEM), implemented in the Zebulon calculation code. The developed approach is validated using the available experimental results reported in the literature. The numerical results showed that the estimation of TRIP given by the energetics criteria with the values of the shear deformation (γ0 = 0.16) are closer to the experiment results.

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