Journal articles on the topic 'Poromechanical behavior'
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1
Rafsanjani, Ahmad, Dominique Derome, and Jan Carmeliet. "Poromechanical modeling of moisture induced swelling anisotropy in cellular tissues of softwoods." RSC Advances 5, no. 5 (2015): 3560–66. http://dx.doi.org/10.1039/c4ra14074e.
Abstract:
In cellular tissues of softwoods, the degree of swelling anisotropy in thin-walled earlywood cells is much larger than in bulky latewood cells. This behavior is simulated by means of a double porosity poromechanical model.
2
Kim, Kiseok, and Roman Y. Makhnenko. "Coupling Between Poromechanical Behavior and Fluid Flow in Tight Rock." Transport in Porous Media 135, no. 2 (October 6, 2020): 487–512. http://dx.doi.org/10.1007/s11242-020-01484-z.
3
Kim, Kiseok, and Roman Y. Makhnenko. "Evolution of poroviscoelastic properties of silica-rich rock after CO2 injection." E3S Web of Conferences 205 (2020): 08007. http://dx.doi.org/10.1051/e3sconf/202020508007.
Abstract:
Injection of CO2 into the subsurface requires consideration of the poromechanical behavior of reservoir rock saturated with aqueous fluid. The material response is usually assumed to be elastic, to avoid consideration of induced seismicity, or viscoelastic, if long-term deformations are needed to be taken into the account. Both elastic and viscous behavior may be influenced by the chemical reactions that are caused by the acidic mixture formed as high-pressure CO2 enters the pore space saturated with aqueous fluid. In this study, we conduct laboratory experiments on a fluid-saturated porous rock - Berea sandstone, and evaluate its poromechanical properties. Subsequently, the specimens are treated with liquid CO2 for 21 days and the corresponding variations in their properties are determined. The constitutive model considering the elastic time-dependent behavior of porous rock is validated by comparing the measured and predicted specimen deformation. Presented data indicate that the effect of CO2 injection on the long-term response is more significant compared to the short-term response. It is suggested for the constitutive models that predict long-term reservoir behavior during CO2 storage to include not only the poroelastic response and its change due to treatment, but also the time-dependent deformation and its evolution caused by the changes in chemistry of the pore fluid.
4
Gmira, A. "Microscopic physical basis of the poromechanical behavior of cement-based materials." Materials and Structures 37, no. 265 (November 27, 2003): 3–14. http://dx.doi.org/10.1617/14101.
5
Zeng, Qiang, Teddy Fen-Chong, Patrick Dangla, and Kefei Li. "A study of freezing behavior of cementitious materials by poromechanical approach." International Journal of Solids and Structures 48, no. 22-23 (November 2011): 3267–73. http://dx.doi.org/10.1016/j.ijsolstr.2011.07.018.
6
Hu, Da Wei, Fan Zhang, and Jian Fu Shao. "Experimental study of poromechanical behavior of saturated claystone under triaxial compression." Acta Geotechnica 9, no. 2 (July 4, 2013): 207–14. http://dx.doi.org/10.1007/s11440-013-0259-y.
7
Gmira, A., M. Zabat, R. J. M. Pellenq, and H. Van Damme. "Microscopic physical basis of the poromechanical behavior of cement-based materials." Materials and Structures 37, no. 1 (January 2004): 3–14. http://dx.doi.org/10.1007/bf02481622.
8
Abbasion, Saeed, Jan Carmeliet, Marjan Sedighi Gilani, Peter Vontobel, and Dominique Derome. "A hygrothermo-mechanical model for wood: part A. Poroelastic formulation and validation with neutron imaging." Holzforschung 69, no. 7 (September 1, 2015): 825–37. http://dx.doi.org/10.1515/hf-2014-0189.
Abstract:
Abstract The correct prediction of the behavior of wood components undergoing environmental loading or industrial process requires that the hygrothermal and mechanical (HTM) behavior of wood is considered in a coupled manner. A fully coupled poromechanical approach is proposed and validated with neutron imaging measurements of moist wood specimens exposed to high temperature. This paper demonstrates that a coupled HTM approach adequately captures the variations of temperature, moisture content, and dimensions that result in a moist wood sample exposed to one-side heating.
9
Abbasion, Saeed, Peter Moonen, Jan Carmeliet, and Dominique Derome. "A hygrothermo-mechanical model for wood: Part B. Parametric studies and application to wood welding." Holzforschung 69, no. 7 (September 1, 2015): 839–49. http://dx.doi.org/10.1515/hf-2014-0190.
Abstract:
Abstract The correct prediction of the behavior of wood components undergoing environmental loading or industrial process requires that the hygric, thermal and mechanical (HTM) behavior of wood are considered in a coupled manner. A fully coupled poromechanical approach has been used to perform a parametric study on wood HTM behavior, and the results have been validated with neutron imaging measurements on a moist wood specimen exposed to high temperature. Further, HTM behavior of wood during welding has been simulated by the model. For such a simulation, proper material properties are needed, as some of them, for example thermal conductivity, have a significant influence on the local and temporal behavior of the material.
10
Loyola, Ana Carolina, Manoel Porfírio Cordão Neto, and Jean-Michel Pereira. "An open-source numerical laboratory to assess the poromechanical behavior of fractured rocks." Computers and Geotechnics 168 (April 2024): 106127. http://dx.doi.org/10.1016/j.compgeo.2024.106127.
11
Barría, Juan Cruz, Diego Manzanal, Jean-Michel Pereira, and Siavash Ghabezloo. "CO2 geological storage: Microstructure and mechanical behavior of cement modified with a biopolymer after carbonation." E3S Web of Conferences 205 (2020): 02007. http://dx.doi.org/10.1051/e3sconf/202020502007.
Abstract:
Large amounts of CO2 could be stored underground in deep rock reservoirs and could help reducing emissions into the environment. Carbon geo-storage technologies have several years in development and new techniques and materials are being studied to make this procedure more effective and less expensive. The risk of leakage from geological reservoirs to other rock formations or even towards the surface means that long-term behavior must be carefully studied. The carbonation of the cement used for sealing the wellbore may compromise the borehole integrity. In light of this problem, this work aims to analyze the poromechanical behavior of cement with and without a new additive in a CO2 environment. Bacterial nanocellulose is a biopolymer that modifies important cement properties such as compressive strength, thermal behavior and hydration degree. Two cement types were studied: class G cement and modified class G cement with bacterial nanocellulose. These samples were submitted to a supercritical CO2 environment (temperatures higher than 32 °C and pressures higher than 8 MPa) during 30 days. Mercury intrusion porosimetry and uniaxial compressive strength tests were performed on these samples to study the effect of carbonation. Both types of cement are affected after carbonation by reducing compressive strength and Young’s modulus (E), however, the strength of modified cement was reduced by 8%, while non-modified cement was reduced by 20%.
12
Jammoul, M., and M. F. Wheeler. "A Phase-Field-Based Approach for Modeling Flow and Geomechanics in Fractured Reservoirs." SPE Journal 27, no. 02 (December 21, 2021): 1195–208. http://dx.doi.org/10.2118/203906-pa.
Abstract:
Summary Modeling the geomechanical deformations of fracture networks has become an integral part of designing enhanced geothermal systems and recovery mechanisms for unconventional reservoirs. Stress changes in the reservoir can cause variations in the apertures of fractures resulting in large changes in their transmissivities. At the same time, sustained high-injection pressures can induce shear slipping along existing fractures and faults and trigger seismic activity. In this work, we extend the phase-field method to solve for flow and geomechanical deformations in naturally fractured reservoirs. The framework can predict the opening/closure of fractures as well as their shear slipping because of induced stresses and poromechanical effects. The flow through fractures is modeled on spatially nonconforming grids using the enhanced velocity mixed finite element method. The geomechanics equations are discretized using the continuous Galerkin (CG) finite element method. The flow and mechanics equations are decoupled using the fixed stress iterative scheme. The implementation is validated against the analytical solutions of Mandel’s problem and Sneddon’s benchmark test. Two synthetic examples are presented to illustrate the impact of poroelastic deformations and the accompanying dynamic behavior of fractures on the safety and productivity of subsurface projects.
13
Couples, Gary D. "Phenomenological understanding of poroelasticity via the micromechanics of a simple digital-rock model." GEOPHYSICS 84, no. 4 (July 1, 2019): WA161—WA182. http://dx.doi.org/10.1190/geo2018-0577.1.
Abstract:
Poroelasticity is a material concept that expresses the reversible, macroscale process interactions that occur in a porous material, such as rocks. These process interactions take place between the pore fluids and the rock framework (or “skeleton”) that contains the pores. The phenomenological basis of poro-elasticity is examined via a micromechanics analysis, using a simplified digital-rock model that consists of solid elements in a lattice arrangement, and which hosts a well-connected, lattice-like network of simply shaped pore elements. The quasistatic poromechanical bulk response of this model is defined fully by closed-form equations that provide a clear understanding of the process interactions and that allow key effects to be identified. Several external boundary conditions (nonisotropic strain and stress) are analyzed, with drained and undrained pore-fluid conditions, along with arbitrary pore pressure states. The calculated responses of the pore-scale model, when translated into continuum-scale equivalent behaviors, indicate significant problems with the existing theories of poroelasticity that are rooted in an enriched-continuum perspective. Specifically, the results indicate that the principle of effective stress (and the Biot coefficient alpha) is wrongly attributed to a deficiency in the role of pore pressure. Instead, the micromechanics-based phenomenological understanding identifies the change of effective stress, in a characteristically confined setting, as being the result of changes in the stress components, with a key dependency on the specifics of the far-field constraints. Thus, poroelasticity is not a material characteristic; instead, it is a description of a nonlinear system operating at the pore scale. The analysis reveals a discrepancy between the stress states within the model domain and the external stress state. This yet remains to be addressed, to translate the microscale behavior into an equivalent material law.
14
Kazemi, M., Y. Dabiri, and L. P. Li. "Recent Advances in Computational Mechanics of the Human Knee Joint." Computational and Mathematical Methods in Medicine 2013 (2013): 1–27. http://dx.doi.org/10.1155/2013/718423.
Abstract:
Computational mechanics has been advanced in every area of orthopedic biomechanics. The objective of this paper is to provide a general review of the computational models used in the analysis of the mechanical function of the knee joint in different loading and pathological conditions. Major review articles published in related areas are summarized first. The constitutive models for soft tissues of the knee are briefly discussed to facilitate understanding the joint modeling. A detailed review of the tibiofemoral joint models is presented thereafter. The geometry reconstruction procedures as well as some critical issues in finite element modeling are also discussed. Computational modeling can be a reliable and effective method for the study of mechanical behavior of the knee joint, if the model is constructed correctly. Single-phase material models have been used to predict the instantaneous load response for the healthy knees and repaired joints, such as total and partial meniscectomies, ACL and PCL reconstructions, and joint replacements. Recently, poromechanical models accounting for fluid pressurization in soft tissues have been proposed to study the viscoelastic response of the healthy and impaired knee joints. While the constitutive modeling has been considerably advanced at the tissue level, many challenges still exist in applying a good material model to three-dimensional joint simulations. A complete model validation at the joint level seems impossible presently, because only simple data can be obtained experimentally. Therefore, model validation may be concentrated on the constitutive laws using multiple mechanical tests of the tissues. Extensive model verifications at the joint level are still crucial for the accuracy of the modeling.
15
Ghabezloo, Siavash, Jean Sulem, Sylvine Guédon, François Martineau, and Jérémie Saint-Marc. "Poromechanical behaviour of hardened cement paste under isotropic loading." Cement and Concrete Research 38, no. 12 (December 2008): 1424–37. http://dx.doi.org/10.1016/j.cemconres.2008.06.007.
16
Sui, Jize. "Dynamic behaviors of sedimenting colloidal gel materials: hydrodynamic interactions." Physical Chemistry Chemical Physics 22, no. 25 (2020): 14340–55. http://dx.doi.org/10.1039/d0cp01563f.
17
Barnafi, Nicolás A., Luis Miguel De Oliveira Vilaca, Michel C. Milinkovitch, and Ricardo Ruiz-Baier. "Coupling Chemotaxis and Growth Poromechanics for the Modelling of Feather Primordia Patterning." Mathematics 10, no. 21 (November 3, 2022): 4096. http://dx.doi.org/10.3390/math10214096.
Abstract:
In this paper we propose a new mathematical model for describing the complex interplay between skin cell populations with fibroblast growth factor and bone morphogenetic protein, occurring within deformable porous media describing feather primordia patterning. Tissue growth, in turn, modifies the transport of morphogens (described by reaction-diffusion equations) through diverse mechanisms such as advection from the solid velocity generated by mechanical stress, and mass supply. By performing an asymptotic linear stability analysis on the coupled poromechanical-chemotaxis system (assuming rheological properties of the skin cell aggregates that reside in the regime of infinitesimal strains and where the porous structure is fully saturated with interstitial fluid and encoding the coupling mechanisms through active stress) we obtain the conditions on the parameters—especially those encoding coupling mechanisms—under which the system will give rise to spatially heterogeneous solutions. We also extend the mechanical model to the case of incompressible poro-hyperelasticity and include the mechanisms of anisotropic solid growth and feedback by means of standard Lee decompositions of the tensor gradient of deformation. Because the model in question involves the coupling of several nonlinear PDEs, we cannot straightforwardly obtain closed-form solutions. We therefore design a suitable numerical method that employs backward Euler time discretisation, linearisation of the semidiscrete problem through Newton–Raphson’s method, a seven-field finite element formulation for the spatial discretisation, and we also advocate the construction and efficient implementation of tailored robust solvers. We present a few illustrative computational examples in 2D and 3D, briefly discussing different spatio-temporal patterns of growth factors as well as the associated solid response scenario depending on the specific poromechanical regime. Our findings confirm the theoretically predicted behaviour of spatio-temporal patterns, and the produced results reveal a qualitative agreement with respect to the expected experimental behaviour. We stress that the present study provides insight on several biomechanical properties of primordia patterning.
18
Selvadurai, A. P. S., and A. P. Suvorov. "Thermo-poromechanics of a fluid-filled cavity in a fluid-saturated geomaterial." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2163 (March 8, 2014): 20130634. http://dx.doi.org/10.1098/rspa.2013.0634.
Abstract:
In this paper, we examine the coupled thermo-poromechanical behaviour of a fluid-saturated porous medium of infinite extent bounded internally by a fluid-filled cavity. The mechanical behaviour of the porous skeleton can either be Hookean elastic or elasto-plastic, with a constitutive response corresponding to a modified Cam Clay plasticity model. The fluid within the cavity can be subjected simultaneously to a temperature rise and a pressure pulse. The paper presents analytical results for the spherically symmetric thermo-poroelasticity problem and these are used to validate the thermo-poroelasticity module of a computational code. We proceed to examine the thermo-poroelasto-plasticity problem. Results presented in the paper illustrate the interaction between thermal and mechanical phenomena and their influence on the cavity fluid pressure and the skeletal stresses at the cavity boundary. The paper presents solutions that will be of value in benchmarking exercises.
19
Selvadurai, A. P. S., and Jueun Kim. "Poromechanical behaviour of a surficial geological barrier during fluid injection into an underlying poroelastic storage formation." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2187 (March 2016): 20150418. http://dx.doi.org/10.1098/rspa.2015.0418.
Abstract:
A competent low permeability and chemically inert geological barrier is an essential component of any strategy for the deep geological disposal of fluidized hazardous material and greenhouse gases. While the processes of injection are important to the assessment of the sequestration potential of the storage formation, the performance of the caprock is important to the containment potential, which can be compromised by the development of cracks and other defects that might be activated during and after injection. This paper presents a mathematical modelling approach that can be used to assess the state of stress in a surficial caprock during injection of a fluid to the interior of a poroelastic storage formation. Important information related to time-dependent evolution of the stress state and displacements of the surficial caprock with injection rates, and the stress state in the storage formation can be obtained from the theoretical developments. Most importantly, numerical results illustrate the influence of poromechanics on the development of adverse stress states in the geological barrier. The results obtained from the mathematical analysis illustrate that the surface heave increases as the hydraulic conductivity of the caprock decreases, whereas the surface heave decreases as the shear modulus of the caprock increases. The results also illustrate the influence of poromechanics on the development of adverse stress states in the caprock.
20
Lion, Maxime, Beatrice Ledesert, Frederic Skoczylas, Philippe Recourt, and Thierry Dubois. "How does micropetrography help us to understand the permeability and poromechanical behaviour of a rock?" Terra Nova 16, no. 6 (December 2004): 351–57. http://dx.doi.org/10.1111/j.1365-3121.2004.00573.x.
21
Ratner, Alon, Richard Beaumont, and Iain Masters. "Dynamic Mechanical Compression Impulse of Lithium-Ion Pouch Cells." Energies 13, no. 8 (April 23, 2020): 2105. http://dx.doi.org/10.3390/en13082105.
Abstract:
Strain rate sensitivity has been widely recognized as a significant feature of the dynamic mechanical properties of lithium-ion cells, which are important for their accurate representation in automotive crash simulations. This research sought to improve the precision with which dynamic mechanical properties can be determined from drop tower impact testing through the use of a diaphragm to minimize transient shock loads and to constrain off-axis motion of the indenter, specialized impact absorbers to reduce noise, and observation of displacement with a high speed camera. Inert pouch cells showed strain rate sensitivity in an increased stiffness during impact tests that was consistent with the poromechanical interaction of the porous structure of the jellyroll with the liquid electrolyte. The impact behaviour of the inert pouch cells was similar to that of an Expanded Polypropylene foam (EPP), with the exception that the inert pouch cells did not show hysteretic recovery under the weight of the indenter. This suggests that the dynamic mechanical behaviour of the inert pouch cells is analogous to a highly damped foam.
22
Carmeliet, J. "Poromechanical approach describing the moisture influence on the non-linear quasi-static and dynamic behaviour of porous building materials." Materials and Structures 37, no. 268 (March 27, 2004): 271–80. http://dx.doi.org/10.1617/14166.
23
Carmeliet, J., and K. Van Den Abeele. "Poromechanical approach describing the moisture influence on the non-linear quasi-static and dynamic behaviour of porous building materials." Materials and Structures 37, no. 4 (May 2004): 271–80. http://dx.doi.org/10.1007/bf02480635.
24
Xie, Wei, Huaizhi Su, Chenfei Shao, and Sen Zheng. "Numerical Analysis and Poromechanics Calculation for Saturated Mortar Involved with Sub-Freezing Temperature." Materials 15, no. 22 (November 8, 2022): 7885. http://dx.doi.org/10.3390/ma15227885.
Abstract:
The individual coupling processes of two-phase materials are controlled to some extent by damage theory. However, the existing theory is not sufficient to explain the effect of pore pressure on mortar materials under freeze-thaw action. In order to predict the resistance of saturated mortars during rapid cooling and to describe the physical behavior of the pore structure, the authors derived in detail the governing equations of saturated mortars during freezing in the framework of the pore elasticity theory and analyzed the sensitivity of physical parameters to the influence of temperature stresses by means of stress-strain calculations. In addition, the effects of phase change and latent heat of freezing on the local thermodynamic equilibrium are considered, and a mathematical model is established for quantitatively simulating the temperature distribution of the specimen. This model is reformulated and extended in the current work to intuitively reveal the effect of concrete dimensions on the temperature hysteresis effect. The results of the numerical model calculations show that during the freezing process, for the specimen with dimensions of 50 mm × 50 mm × 50 mm and a water-cement ratio of 0.6, the maximum temperature difference from center to surface is 10 °C, the maximum vertical strain on the surface is 4.27 × 10−4, and the maximum pore water pressure at the center of the specimen is 76 MPa. The model calculation results present a similar pattern to the physical interpretation and reference results, thus effectively evaluating the freezing damage process of saturated mortar.
25
Vadillo-Sáenz, M. E., P. F. Aguilar-Gasteum, M. A. Díaz-Viera, and M. Coronado. "Permeability simulation in an elastic deformable sandstone under stress changes." Suplemento de la Revista Mexicana de Física 1, no. 2 (July 16, 2020): 25–33. http://dx.doi.org/10.31349/suplrevmexfis.1.2.25.
Abstract:
Fluid flow and rock mechanics become coupled in various important phenomena in Geosciences. In order to study this coupling, laboratory work has been carried out in triaxial cells along the years for various rock and fluid types at different confinement stress and pore pressure conditions. In a similar way, poromechanic models have been developed to simulate them, in which constitutive porosity and permeability correlation models in terms of strain, stress and fluid pressure have to be provided. However, to date, the applicability of the available correlation models to describe this phenomenon in different types of rock remains to be analyzed. In this work, a single-phase poroelastic model is applied to simulate a published geomechanical test performed in sandstones to examine the capacity of commonly used constitutive porosity and permeability correlations to describe the behavior of a homogeneous poroelastic medium. After discussing the results, we conclude that for this sandstone, the best permeability constitutive correlation model is Walder and Nur.
26
Zadran, Sekandar, Joško Ožbolt, and Serena Gambarelli. "Numerical Analysis of the Freezing Behavior of Saturated Cementitious Materials with Different Amounts of Chloride." Materials 16, no. 19 (October 8, 2023): 6594. http://dx.doi.org/10.3390/ma16196594.
Abstract:
The freezing behavior of cement paste saturated with different chloride concentrations is investigated numerically with a coupled 3D hygro-thermo-mechanical FE analysis. The mathematical formulation of the freezing processes in the context of poromechanics takes into account the water (hydraulic) and ice pore pressures, as well as the distribution of heat (temperature) and strains. These quantities are calculated numerically based on three coupled differential equations, namely the static equilibrium equation and the equations for the transport of water and heat. The coupling between the mechanical (loading) and the non-mechanical processes (freezing) is performed using a staggered solution scheme. The proposed numerical approach is first validated using numerical and experimental studies from the literature dealing with two different cement pastes saturated with different amounts of chloride. The validated model is then used to investigate the effects of liquid water permeability, total porosity and pore size distribution on the freezing behavior of hardened cement paste. The results show that liquid water permeability has a strong effect on the pore pressure and deformation of the hardened cement paste. It is also shown that by decreasing the total porosity, the material becomes denser and contracts more as the temperature decreases, leading to a decrease in freezing strain. The results of this paper will provide important findings for the development of a simplified engineering model to investigate the mechanism that leads to freeze–thaw salt-induced damage to concrete structures in the framework of the DFG-funded research project.
27
Sharifi, Javad. "Dynamic-to-static modeling." GEOPHYSICS 87, no. 2 (February 10, 2022): MR63—MR72. http://dx.doi.org/10.1190/geo2020-0778.1.
Abstract:
Dynamic-to-static (DTS) modulus conversion has long been recognized as a complicated and challenging task in reservoir characterization and seismic geomechanics, and many single- and two-variable regression equations have been proposed. In practice, however, the form and constants of the regression equation are variable from case to case. I have introduced a methodology for estimating the static moduli called DTS modeling. The methodology is validated by laboratory tests (ultrasonic and triaxial compression tests) to obtain dynamic and quasistatic bulk and Young’s (elasticity) moduli. Then, rock deformation phenomena are simulated considering different parameters affecting the process. The dynamic behavior is further modeled using rock physics methods. Unlike conventional DTS conversion procedures, this method considers a wide range of factors affecting the relationship between dynamic and static moduli, including strain amplitude, dispersion, rock failure mechanism, pore shape, crack parameters, poromechanics, and upscaling. A comparison of data from laboratory and in situ tests and estimation results indicates promising findings. The accuracy of the results is assessed by analysis of variance. In addition to modeling static moduli, DTS can be used to verify static and dynamic moduli values with appropriate accuracy when core data are not available.
28
Maghoul, Pooneh, and Behrouz Gatmiri. "Theory of a Time Domain Boundary Element Development for the Dynamic Analysis of Coupled Multiphase Porous Media." Journal of Multiscale Modelling 08, no. 03n04 (September 2017): 1750007. http://dx.doi.org/10.1142/s175697371750007x.
Abstract:
This paper presents an advanced formulation of the time-domain two-dimensional (2D) boundary element method (BEM) for an elastic, homogeneous unsaturated soil subjected to dynamic loadings. Unlike the usual time-domain BEM, the present formulation applies a convolution quadrature which requires only the Laplace-domain instead of the time-domain fundamental solutions. The coupled equations governing the dynamic behavior of unsaturated soils ignoring contributions of the inertia effects of the fluids (water and air) are derived based on the poromechanics theory within the framework of a suction-based mathematical model. In this formulation, the solid skeleton displacements [Formula: see text], water pressure [Formula: see text] and air pressure [Formula: see text] are presumed to be independent variables. The fundamental solutions in Laplace transformed-domain for such a dynamic [Formula: see text] theory have been obtained previously by authors. Then, the BE formulation in time is derived after regularization by partial integrations and time and spatial discretizations. Thereafter, the BE formulation is implemented in a 2D boundary element code (PORO-BEM) for the numerical solution. To verify the accuracy of this implementation, the displacement response obtained by the boundary element formulation is verified by comparison with the elastodynamics problem.
29
Pashazad, Hossein, and Xiaoyu Song. "Shear Banding and Cracking in Unsaturated Porous Media through a Nonlocal THM Meshfree Paradigm." Geosciences 14, no. 4 (April 9, 2024): 103. http://dx.doi.org/10.3390/geosciences14040103.
Abstract:
The mechanical behavior of unsaturated porous media under non-isothermal conditions plays a vital role in geo-hazards and geo-energy engineering (e.g., landslides triggered by fire and geothermal energy harvest and foundations). Temperature increase can trigger localized failure and cracking in unsaturated porous media. This article investigates the shear banding and cracking in unsaturated porous media under non-isothermal conditions through a thermo–hydro–mechanical (THM) periporomechanics (PPM) paradigm. PPM is a nonlocal formulation of classical poromechanics using integral equations, which is robust in simulating continuous and discontinuous deformation in porous media. As a new contribution, we formulate a nonlocal THM constitutive model for unsaturated porous media in the PPM paradigm in this study. The THM meshfree paradigm is implemented through an explicit Lagrangian meshfree algorithm. The return mapping algorithm is used to implement the nonlocal THM constitutive model numerically. Numerical examples are presented to assess the capability of the proposed THM mesh-free paradigm for modeling shear banding and cracking in unsaturated porous media under non-isothermal conditions. The numerical results are examined to study the effect of temperature variations on the formation of shear banding and cracking in unsaturated porous media.
30
Dagher, Elias Ernest, Julio Ángel Infante Sedano, and Thanh Son Nguyen. "A Mathematical Model of Gas and Water Flow in a Swelling Geomaterial—Part 2. Process Simulation." Minerals 10, no. 1 (December 29, 2019): 32. http://dx.doi.org/10.3390/min10010032.
Abstract:
Gases can potentially generate in a deep geological repository (DGR) for the long-term containment of radioactive waste. Natural and engineered barriers provide containment of the waste by mitigating contaminant migration. However, if gas pressures exceed the mechanical strength of these barriers, preferential flow pathways for both the gases and the porewater could form, providing a source of potential exposure to people and the environment. Expansive soils, such as bentonite-based materials, are widely considered as sealing materials. Understanding the long-term performance of these seals as barriers against gas migration is an important component in the design and the long-term safety assessment of a DGR. This study proposes a hydro-mechanical mathematical model for migration of gas through a low-permeable swelling geomaterial based on the theoretical framework of poromechanics. Using the finite element method, the model is used to simulate 1D flow through a confined cylindrical sample of near-saturated low-permeable soil under a constant volume boundary stress condition. The study expands upon previous work by the authors by assessing the influence of heterogeneity, the Klinkenberg “slip flow” effect, and a swelling stress on flow behavior. Based on the results, this study provides fundamental insight into a number of factors that may influence two-phase flow.
31
Nasir, O., T. S. Nguyen, J. D. Barnichon, and A. Millard. "Simulation of hydromechanical behaviour of bentonite seals for containment of radioactive wastes." Canadian Geotechnical Journal 54, no. 8 (August 2017): 1055–70. http://dx.doi.org/10.1139/cgj-2016-0102.
Abstract:
Geological disposal of radioactive wastes relies on a multiple barrier system to provide long-term containment and isolation of the wastes. The excavation of the repository creates openings and disturbed zones in the host rock formations that need to be properly sealed. Bentonite-based materials are being considered worldwide as a preferred type of sealing material, since they possess desirable characteristics such as low permeability, high sorption capability, and swelling potential allowing them to close internal cracks and gaps at interfaces with other materials. The French Institute for Radiation Protection and Nuclear Safety (IRSN) has led an experimental program consisting of a series of laboratory and large in situ experiments to assess the hydromechanical behaviour of bentonite seals. The experiments consisted of the forced re-saturation of pre-fabricated blocks of bentonite–sand mixture, with technological voids between bentonite seals and the walls of the steel cell (in the laboratory tests) and between bentonite seals and the host rock (in the in situ experiment). Relative humidity and total stress were monitored during both tests. The Canadian Nuclear Safety Commission (CNSC) collaborated with Geofirma Engineering, IRSN, and Commissariat à l’énergie atomique (CEA) to develop a mathematical model to simulate the experiments. The model was developed within the framework of poromechanics, with the inclusion of partial saturation characteristics and swelling potential to simulate the behaviour of the bentonite-based material. The model results were in good agreement with the experimental measurements for relative humidity and swelling stresses. The model also predicted the closure of technological voids and gaps due to swelling. Although swelling into the technological voids leads to an increase in permeability, that permeability remains low and insignificant from a safety perspective.
32
Chen, Bowen, Hicham Chaouki, Donald Picard, Julien Lauzon-Gauthier, Houshang Alamdari, and Mario Fafard. "Modeling of Thermo-Chemo-Mechanical Properties of Anode Mixture during the Baking Process." Materials 14, no. 15 (August 2, 2021): 4320. http://dx.doi.org/10.3390/ma14154320.
Abstract:
In the Hall–Héroult process, prebaked carbon anodes are utilized to produce primary aluminium. The quality of the anode plays a crucial role in the efficiency of electrowinning primary aluminium. In the production of anodes, the anode baking is considered as the stage most frequently causing anode problems. During the baking process, the anode undergoes complex physicochemical transformations. Moreover, the anode at a lower position, imposed by loading pressures from upper anodes, will creep during this process. Thus, the production of high-quality anodes demands efficient control of their baking process. This paper aims to investigate the thermo-chemo-mechanical properties of the anode paste mixture at high temperatures. These properties include kinetic parameters of pitch pyrolysis such as the activation energy and the pre-exponential factor, the thermal expansion coefficient (TEC) and relevant mechanical parameters related to the elastic, the viscoelastic and the viscoplastic behaviours of the anode. For this purpose, experiments consisting of the thermogravimetric analysis, the dilatometry and the creep test were carried out. Based on the obtained results, the forementioned parameters were identified. Relevant mechanical parameters were expressed as a function of a new variable, called the shrinking index, which is related to the volatile released in open and closed pores of the anode. This variable would be used to highlight the chemo-mechanical coupling effect of the anode mixture. New insights into the phenomena such as the expansion due to the increase of the pore pressure and the chemical shrinkage of the anode during the baking process were also gained in this work. These investigations pave the way for modeling the thermo-chemo-poromechanical behaviour of the anode during the baking process.
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Bulle, Raphaël, Gioacchino Alotta, Gregorio Marchiori, Matteo Berni, Nicola F. Lopomo, Stefano Zaffagnini, Stéphane P. A. Bordas, and Olga Barrera. "The Human Meniscus Behaves as a Functionally Graded Fractional Porous Medium under Confined Compression Conditions." Applied Sciences 11, no. 20 (October 11, 2021): 9405. http://dx.doi.org/10.3390/app11209405.
Abstract:
In this study, we observe that the poromechanical parameters in human meniscus vary spatially throughout the tissue. The response is anisotropic and the porosity is functionally graded. To draw these conclusions, we measured the anisotropic permeability and the “aggregate modulus” of the tissue, i.e., the stiffness of the material at equilibrium, after the interstitial fluid has ceased flowing. We estimated those parameters within the central portion of the meniscus in three directions (i.e., vertical, radial and circumferential) by fitting an enhanced model on stress relation confined compression tests. We noticed that a classical biphasic model was not sufficient to reproduce the observed experimental behaviour. We propose a poroelastic model based on the assumption that the fluid flow inside the human meniscus is described by a fractional porous medium equation analogous to Darcy’s law, which involves fractional operators. The fluid flux is then time-dependent for a constant applied pressure gradient (in contrast with the classical Darcy’s law, which describes a time independent fluid flux relation). We show that a fractional poroelastic model is well-suited to describe the flow within the meniscus and to identify the associated parameters (i.e., the order of the time derivative and the permeability). The results indicate that mean values of λβ,β in the central body are λβ=5.5443×10−10m4Ns1−β, β=0.0434, while, in the posterior and anterior regions, are λβ=2.851×10−10m4Ns1−β, β=0.0326 and λβ=1.2636×10−10m4Ns1−β, β=0.0232, respectively. Furthermore, numerical simulations show that the fluid flux diffusion is facilitated in the central part of the meniscus and hindered in the posterior and anterior regions.
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Dagher, E. E., T. S. Nguyen, and J. A. Infante Sedano. "Development of a mathematical model for gas migration (two-phase flow) in natural and engineered barriers for radioactive waste disposal." Geological Society, London, Special Publications 482, no. 1 (November 29, 2018): 115–48. http://dx.doi.org/10.1144/sp482.14.
Abstract:
AbstractIn a deep geological repository (DGR) for the long-term containment of radioactive waste, gases could be generated through a number of processes. If gas production exceeds the containment capacity of the engineered barriers or host rock, these gases could migrate through these barriers and potentially expose people and the environment to radioactivity. Expansive soils, such as bentonite-based materials, are currently the preferred choice of seal materials. Understanding the long-term performance of these seals as barriers against gas migration is an important component in the design and long-term safety assessment of a DGR. This study proposes a hydro-mechanical linear poro-elastic visco-capillary mathematical model for advective-diffusive controlled two-phase flow through a low-permeability expansive soil. It is based on the theoretical framework of poromechanics, incorporates Darcy's Law for both the porewater and poregas, and a modified Bishop's effective stress principle. Using the finite element method (FEM), the model was used to numerically simulate 1D flow through a low-permeability expansive soil. The results were verified against experimental results found in the current literature. Parametric studies were performed to determine the influence on the flow behaviour. Based on the results, the mathematical model looks promising and will be improved to model flow through preferential pathways.
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Witrant, E., P. Martinerie, C. Hogan, J. C. Laube, K. Kawamura, E. Capron, S. A. Montzka, et al. "A new multi-gas constrained model of trace gas non-homogeneous transport in firn: evaluation and behavior at eleven polar sites." Atmospheric Chemistry and Physics Discussions 11, no. 8 (August 16, 2011): 23029–80. http://dx.doi.org/10.5194/acpd-11-23029-2011.
Abstract:
Abstract. Insoluble trace gases are trapped in polar ice at the firn-ice transition, at approximately 50 to 100 m below the surface, depending primarily on the site temperature and snow accumulation. Due to the different time scales for snow accumulation versus diffusion of gases through the snowpack, age differences between gases and the ice in which they are "trapped" can be large; e.g. several thousand years in central Antarctica (a low snow accumulation area). Models of trace gas diffusion in polar firn are used to relate firn air and ice core records of trace gases to their atmospheric history. We propose a new diffusion model based on the following contributions. First, the airflow transport model is revised in a poromechanics framework with specific emphasis on the non-homogeneous properties (convective layer, depth-dependent diffusivity and lock-in zone) and an almost-stagnant behavior described by Darcy's law (gravity effect). We then derive a non-linear least square multi-gas optimization scheme to calculate the effective firn diffusivity (automatic diffusivity tuning). The improvements associated with the additional constraints gained by the multi-gas approach are investigated (up to eleven gases for a single site are included in the optimization process). The model is applied to measured data from four Arctic (Devon Island, NEEM, North GRIP, Summit) and seven Antarctic (DE08, Berkner Island, Siple Dome, Dronning Maud Land, South Pole, Dome C, Vostok) sites and the depth-dependent diffusivity profiles are calculated. Among these different sites, a relationship between an increasing thickness of the lock-in zone defined from the isotopic composition of molecular nitrogen in firn air (denoted δ15N) and the snow accumulation rate is obtained, in accordance with observations. It is associated with reduced diffusivity depth-gradients in deep firn, which decreases gas density depth-gradients, at high accumulation rate sites. This has implications for the understanding of δ15N of N2 records in ice cores, in relation with past variations of the snow accumulation rate. Although the extent of layering is clearly a primary control on the thickness of the lock-in zone, our new approach that allows calculation of an estimated lock-in depth may lead to a better constraint on the age difference between the ice and entrapped gases.
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Witrant, E., P. Martinerie, C. Hogan, J. C. Laube, K. Kawamura, E. Capron, S. A. Montzka, et al. "A new multi-gas constrained model of trace gas non-homogeneous transport in firn: evaluation and behaviour at eleven polar sites." Atmospheric Chemistry and Physics 12, no. 23 (December 4, 2012): 11465–83. http://dx.doi.org/10.5194/acp-12-11465-2012.
Abstract:
Abstract. Insoluble trace gases are trapped in polar ice at the firn-ice transition, at approximately 50 to 100 m below the surface, depending primarily on the site temperature and snow accumulation. Models of trace gas transport in polar firn are used to relate firn air and ice core records of trace gases to their atmospheric history. We propose a new model based on the following contributions. First, the firn air transport model is revised in a poromechanics framework with emphasis on the non-homogeneous properties and the treatment of gravitational settling. We then derive a nonlinear least square multi-gas optimisation scheme to calculate the effective firn diffusivity (automatic diffusivity tuning). The improvements gained by the multi-gas approach are investigated (up to ten gases for a single site are included in the optimisation process). We apply the model to four Arctic (Devon Island, NEEM, North GRIP, Summit) and seven Antarctic (DE08, Berkner Island, Siple Dome, Dronning Maud Land, South Pole, Dome C, Vostok) sites and calculate their respective depth-dependent diffusivity profiles. Among these different sites, a relationship is inferred between the snow accumulation rate and an increasing thickness of the lock-in zone defined from the isotopic composition of molecular nitrogen in firn air (denoted δ15N). It is associated with a reduced diffusivity value and an increased ratio of advective to diffusive flux in deep firn, which is particularly important at high accumulation rate sites. This has implications for the understanding of δ15N of N2 records in ice cores, in relation with past variations of the snow accumulation rate. As the snow accumulation rate is clearly a primary control on the thickness of the lock-in zone, our new approach that allows for the estimation of the lock-in zone width as a function of accumulation may lead to a better constraint on the age difference between the ice and entrapped gases.
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Winhausen, L., K. Khaledi, M. Jalali, M. Bretthauer, and F. Amann. "The Anisotropic Behavior of a Clay Shale: Strength, Hydro‐Mechanical Couplings and Failure Processes." Journal of Geophysical Research: Solid Earth 128, no. 11 (November 2023). http://dx.doi.org/10.1029/2023jb027382.
Abstract:
AbstractMany rocks exhibit a structural composition, which leads to an anisotropic behavior of different properties. A proper understanding of the directional dependency of these properties is required to analyze and predict the failure behavior of the rock mass upon stress changes during many geo‐engineering applications. This study investigates the selected host rock for nuclear waste disposal in Switzerland, Opalinus Clay, for its anisotropic unconfined compressive and tensile strength, poromechanical response, and effective shear strength in an extensive laboratory testing campaign. The results show the lowest unconfined compressive strength at angles of 30°–45° between the bedding plane and the compressive load direction, whereby the lowest tensile strength is found to be normal to the bedding orientation. Triaxial consolidated‐undrained compression tests reveal an anisotropic poromechanical behavior as well as peak and residual effective strength values, which are largely controlled by the orientation of the bedding plane with respect to the maximum principal stress. The magnitude of excess pore water pressures and dilation are both functions of loading configuration. The comparison of peak strength values for different loading angles indicates that the lowest effective shear strength can be expected at a loading configuration of approximately 45° between bedding orientation and the loading axis. The variation in the hydro‐mechanical response is associated with the microstructure controlling the poroelasticity and the failure processes. The results provide a deeper understanding of failure in anisotropic rocks contributing to the development of constitutive models for predicting the rock mass response.
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Shi, Yuhao, and Thomas Wallmersperger. "A finite strain chemo-poro-mechanical framework for the chemically stimulated permeation of fluid in polymer gels." Journal of Intelligent Material Systems and Structures, May 8, 2022, 1045389X2210933. http://dx.doi.org/10.1177/1045389x221093347.
Abstract:
Polyelectrolyte polymer gels can significantly increase or decrease their volume by an external stimulus. The reason for this ability is the multiphasic structure of the gel. In the present work, a chemo-electro-poromechanical model is presented, which is supposed to map the swelling behavior of chemically stimulated polymer gels. The presented model was implemented in COMSOL Multiphysics®, and the swelling behavior of an acrylamide gel was simulated afterward. The mechanical parameters were obtained from experimental data using a least square optimization while the other material parameters were calibrated to the experimentally determined swelling behavior.
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Pandey, Rohit, and Satya Harpalani. "Understanding poromechanical response of a biogenic coalbed methane reservoir." International Journal of Coal Science & Technology 11, no. 1 (April 17, 2024). http://dx.doi.org/10.1007/s40789-024-00686-w.
Abstract:
AbstractBiogenic coalbed methane (BCBM) reservoirs aim to produce methane from in situ coal deposits following microbial conversion of coal. Success of BCBM reservoirs requires economic methane production within an acceptable timeframe. The work reported here quantifies the findings of previously published qualitative work, where it was found that bioconversion induces strains in the pore, matrix and bulk scales. Using imaging and dynamic strain monitoring techniques, the bioconversion induced strain is quantified here. To understand the effect of these strains from a reservoir geomechanics perspective, a corresponding poromechanical model is developed. Furthermore, findings of imaging experiments are validated using core-flooding flow experiments. Finally, expected field-scale behavior of the permeability response of a BCBM operation is modeled and analyzed. The results of the study indicated that, for Illinois coals, bioconversion induced strains result in a decrease in fracture porosity, resulting in a detrimental permeability drop in excess of 60% during bioconversion, which festers itself exponentially throughout its producing life. Results indicate that reservoirs with high initial permeability that will support higher Darcian flowrates, would be better suited for coal bioconversion, thereby providing a site-selection criteria for BCBM operations.
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Shi, Yuhao, and Thomas Wallmersperger. "Poromechanical modeling of fluid penetration in chemo-responsive gels: Parameter optimization and applications." Journal of Intelligent Material Systems and Structures, November 6, 2023. http://dx.doi.org/10.1177/1045389x231201039.
Abstract:
As an important category of smart materials, stimuli-responsive hydrogels are highly concerned due to their extensive application possibilities and their outstanding biocompatibilities. The ability of responsive hydrogels about significant volume change by external stimuli inspires the design of electronic devices, for example, as sensors and actuators. The modeling of the hydrogel behavior enables the optimization of corresponding applications. In the present research, on the basis of the experimentally determined material parameters, a chemo-poromechanical model was implemented in COMSOL Multiphysics® to investigate the constricted swelling of hydrogels. The swelling kinetics affected by the diffusion coefficient is discussed in detail with numerical simulations.
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Avilés-Rojas, Nibaldo, and Daniel E. Hurtado. "Whole-lung finite-element models for mechanical ventilation and respiratory research applications." Frontiers in Physiology 13 (October 4, 2022). http://dx.doi.org/10.3389/fphys.2022.984286.
Abstract:
Mechanical ventilation has been a vital treatment for Covid-19 patients with respiratory failure. Lungs assisted with mechanical ventilators present a wide variability in their response that strongly depends on air-tissue interactions, which motivates the creation of simulation tools to enhance the design of ventilatory protocols. In this work, we aim to create anatomical computational models of the lungs that predict clinically-relevant respiratory variables. To this end, we formulate a continuum poromechanical framework that seamlessly accounts for the air-tissue interaction in the lung parenchyma. Based on this formulation, we construct anatomical finite-element models of the human lungs from computed-tomography images. We simulate the 3D response of lungs connected to mechanical ventilation, from which we recover physiological parameters of high clinical relevance. In particular, we provide a framework to estimate respiratory-system compliance and resistance from continuum lung dynamic simulations. We further study our computational framework in the simulation of the supersyringe method to construct pressure-volume curves. In addition, we run these simulations using several state-of-the-art lung tissue models to understand how the choice of constitutive models impacts the whole-organ mechanical response. We show that the proposed lung model predicts physiological variables, such as airway pressure, flow and volume, that capture many distinctive features observed in mechanical ventilation and the supersyringe method. We further conclude that some constitutive lung tissue models may not adequately capture the physiological behavior of lungs, as measured in terms of lung respiratory-system compliance. Our findings constitute a proof of concept that finite-element poromechanical models of the lungs can be predictive of clinically-relevant variables in respiratory medicine.
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Chen, Bowen, Hicham Chaouki, Donald Picard, Donald Ziegler, Houshang Alamdari, and Mario Fafard. "Thermo-Chemo-Poromechanical Modeling of the Anode Mixture During the Baking Process: Constitutive Laws and Governing Equations." Journal of Applied Mechanics 87, no. 1 (October 14, 2019). http://dx.doi.org/10.1115/1.4044665.
Abstract:
Abstract Aluminum is reduced from alumina by the Hall–Héroult electrolysis process in which the anode is utilized as the positive electrode. The quality of the prebaked anode plays a crucial rule in the efficiency of the aluminum electrolysis process. To produce high-quality anodes in the aluminum industry, the anode baking process calls for a deep understanding of mechanisms that govern the evolution of the anode mixture properties under the high-temperature condition. Therefore, the aim of this paper is to establish a thermo-chemo-poromechanical model for the baking anode by using the theory of reactive porous media based on the theory of mixtures within the thermodynamic framework. For this purpose, an internal state variable called “shrinking index” is defined to characterize the chemical progress of the pitch pyrolysis in the anode skeleton, and the Clausius–Duhem inequality is developed according to the Lagrangian formalism. By introducing a reduced Green–Lagrange strain tensor, a Lagrangian free energy is formulated to found a set of state equations. Then, the thermodynamic dissipation for this pyrolyzing solid–gas mixture is derived, and a constitutive model linking the chemical pyrolysis with the mechanical behavior is achieved. A dissipation potential is consistently defined to ensure the non-negativeness of the thermodynamic dissipation and to obtain the constitutive laws for viscous behaviors. Field equations governing the volatile diffusion and the heat transfer through the draining mixture body are derived from the entropy balance.
43
Rey, Justine, and Matthieu Vandamme. "On the Shrinkage and Stiffening of a Cellulose Sponge Upon Drying." Journal of Applied Mechanics 80, no. 2 (February 6, 2013). http://dx.doi.org/10.1115/1.4007906.
Abstract:
Everyone can observe the peculiar effect of water on a sponge: upon drying, a sponge shrinks and stiffens; it swells and softens upon wetting. In this work, we aim to explain and model this behavior by using the Biot–Coussy poromechanical framework. We measure the volume and the bulk modulus of sponges at different water contents. Upon drying, the volume of the sponge decreases by more than half and its bulk modulus increases by almost two orders of magnitude. We develop a partially saturated microporomechanical model of the sponge undergoing finite transformations. The model compares well with the experimental data. We show that about half of the stiffening of the sponge upon drying is due to geometrical nonlinearities induced by a closing of the pores under the action of capillary pressure. The other half of the stiffening can be explained by the nonlinear elastic properties of the cellulose material itself.
44
Patte, Cécile, Pierre-Yves Brillet, Catalin Fetita, Jean-François Bernaudin, Thomas Gille, Hilario Nunes, Dominique Chapelle, and Martin Genet. "Estimation of Regional Pulmonary Compliance in Idiopathic Pulmonary Fibrosis Based on Personalized Lung Poromechanical Modeling." Journal of Biomechanical Engineering 144, no. 9 (March 30, 2022). http://dx.doi.org/10.1115/1.4054106.
Abstract:
Abstract Pulmonary function is tightly linked to the lung mechanical behavior, especially large deformation during breathing. Interstitial lung diseases, such as idiopathic pulmonary fibrosis (IPF), have an impact on the pulmonary mechanics and consequently alter lung function. However, IPF remains poorly understood, poorly diagnosed, and poorly treated. Currently, the mechanical impact of such diseases is assessed by pressure–volume curves, giving only global information. We developed a poromechanical model of the lung that can be personalized to a patient based on routine clinical data. The personalization pipeline uses clinical data, mainly computed tomography (CT) images at two time steps and involves the formulation of an inverse problem to estimate regional compliances. The estimation problem can be formulated both in terms of “effective”, i.e., without considering the mixture porosity, or “rescaled,” i.e., where the first-order effect of the porosity has been taken into account, compliances. Regional compliances are estimated for one control subject and three IPF patients, allowing to quantify the IPF-induced tissue stiffening. This personalized model could be used in the clinic as an objective and quantitative tool for IPF diagnosis.
45
Bonaldi, Francesco, Jérôme Droniou, and Roland Masson. "Numerical analysis of a mixed-dimensional poromechanical model with frictionless contact at matrix–fracture interfaces." Mathematics of Computation, March 7, 2024. http://dx.doi.org/10.1090/mcom/3949.
Abstract:
We present a complete numerical analysis for a general discretization of a coupled flow–mechanics model in fractured porous media, considering single-phase flows and including frictionless contact at matrix–fracture interfaces, as well as nonlinear poromechanical coupling. Fractures are described as planar surfaces, yielding the so-called mixed- or hybrid-dimensional models. Small displacements and a linear elastic behavior are considered for the matrix. The model accounts for discontinuous fluid pressures at matrix–fracture interfaces in order to cover a wide range of normal fracture conductivities. The numerical analysis is carried out in the Gradient Discretization framework (see J. Droniou, R. Eymard, T. Gallouët, C. Guichard, and R. Herbin [The gradient discretisation method, Springer, Cham, 2018]), encompassing a large family of conforming and nonconforming discretizations. The convergence result also yields, as a by-product, the existence of a weak solution to the continuous model. A numerical experiment in 2D is presented to support the obtained result, employing a Hybrid Finite Volume scheme for the flow and second-order finite elements ( P 2 \mathbb {P}_2 ) for the mechanical displacement coupled with face-wise constant ( P 0 \mathbb P_0 ) Lagrange multipliers on fractures, representing normal stresses, to discretize the contact conditions.
46
Sarvaramini, Erfan, Maurice B. Dusseault, and Robert Gracie. "Characterizing the Stimulated Reservoir Volume During Hydraulic Fracturing-Connecting the Pressure Fall-Off Phase to the Geomechanics of Fracturing." Journal of Applied Mechanics 85, no. 10 (July 3, 2018). http://dx.doi.org/10.1115/1.4040479.
Abstract:
Microseismic imaging of the hydraulic fracturing operation in the naturally fractured rocks confirms the existence of a stimulated volume (SV) of enhanced permeability. The simulation and characterization of the SV evolution is uniquely challenging given the uncertainty in the nature of the rock mass fabrics as well as the complex fracturing behavior of shear and tensile nature, irreversible plastic deformation and damage. In this paper, the simulation of the SV evolution is achieved using a nonlocal poromechanical plasticity model. Effects of the natural fracture network are incorporated via a nonlocal plasticity characteristic length, ℓ. A nonlocal Drucker–Prager failure model is implemented in the framework of Biot's theory using a new implicit C0 finite element method. First, the behavior of the SV for a two-dimensional (2D) geomechanical injection problem is simulated and the resulting SV is assessed. It is shown that breakdown pressure and stable fracturing pressure are the natural outcomes of the model and both depend upon ℓ. Next, the post-shut-in behavior of the SV is analyzed using the pressure and pressure derivative plots. A bilinear flow regime is observed and it is used to estimate the flow capacity of the SV. The results show that the flow capacity of the SV increases as ℓ decreases (i.e., as the SV behaves more like a single hydraulic fracture); however, for 0.1m≤ℓ≤1m, the calculated flow capacity indicates that the conductivity of the SV is finite. Finally, it is observed that as ℓ tends to zero, the flow capacity of the SV tends to infinity and the SV behaves like a single infinitely conducting fracture.
47
Bardella, Lorenzo, and Andrea Panteghini. "Electrochemo-poromechanics of ionic polymer metal composites: Identification of the model parameters." Smart Materials and Structures, October 16, 2023. http://dx.doi.org/10.1088/1361-665x/ad0396.
Abstract:
Abstract We propose a procedure to identify the parameters of a model for the multiphysics response of ionic polymer metal composites (IPMCs). Aiming at computational efficiency and accuracy, the procedure combines analytical structural mechanics and fully-coupled electrochemo-poromechanics, additionally resorting to an evolutionary algorithm. Specifically, we consider the finite-deformation electrochemo-poromechanical theory recently developed by our group, which couples the linear momentum balance, the mass balances of solvent and mobile ions, and the Gauss law. Remarkably, the theory constitutively accounts for the cross-diffusion of solvent and mobile ions. This, in conjunction with a generalized finite element implementation that we have recently proposed, allows us to accurately capture the boundary layers of ions and solvent concentrations occurring at the membrane-electrode interfaces, which govern the IPMC behaviour in actuation and short-circuit sensing. Thus, we can explore the IPMC behaviour under external actions consistent with applications and obtain accurate predictions with a reasonable computational cost for wide ranges of model parameters. We focus on experimental data from the literature that are concerned with Nafion-Pt IPMCs of variable membrane thickness and subjected to peak voltage drop across the electrodes ranging from 2 to 3.5 V (under alternating current). Importantly, the considered tests deal with both the tip displacement of cantilever IPMCs and the blocking force of propped-cantilever IPMCs. Overall, the adopted theory and the proposed procedure allow unprecedented agreement between predictions and experimental data, thus marking a step forward in the IPMC characterisation.
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Agofack, Nicolaine, Pierre Cerasi, Eyvind Sønstebø, and Jørn Stenebråten. "Thermo-Poromechanical Properties of Pierre II Shale." Rock Mechanics and Rock Engineering, August 10, 2022. http://dx.doi.org/10.1007/s00603-022-02994-6.
Abstract:
AbstractDuring the injection of carbon dioxide (CO2) for CO2 capture and storage (CCS) operations, the near-well (including casing, cement, and rock around it) can undergo several thermal loadings. These loadings can significantly increase or decrease the pore pressure and can thus lead to mechanical failure of the cement sheath and rock formation. When these failures appear in the caprock, they can compromise the integrity of the storage site. The understanding of thermo-mechanical behaviour of a potential caprock shale is, therefore, of great importance for the success of CCS operations. In this paper, experiments were performed on Pierre II shale, under confining and initial pore pressures comparable to field conditions. A 60 °C loading amplitude (between 30 and 90 °C) was applied on the shale material both under undrained and drained conditions. The results, analysed within the framework of anisotropic thermo-poro-elasticity, highlight the anisotropic behaviour of the thermal expansion coefficients, as well as of the Skempton coefficient. The thermal pressurization coefficient was also evaluated and showed a potential pore pressure change as high as 0.11 MPa/°C.
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Manzanal, Diego, Jean-Michel Pereira, and Juan Cruz Barría. "Analysis of biopolymer modified oil cement under supercritical CO2." Symposium on Energy Geotechnics 2023, October 4, 2023, 1–2. http://dx.doi.org/10.59490/seg.2023.645.
Abstract:
Storing CO2 in deep underground reservoirs is key to reducing emissions to the atmosphere and standing against climate change. However, the risk of CO2 leakage from geological reservoirs to other rock formations requires a careful long-term analysis of the system. Mostly, oil well cement used for the operation must withstand the carbonation process that changes its poromechanical behavior over time, possibly affecting the system’s integrity.The use of nanoadditives for cement, such as bacterial nanocellulose (BNC), has been increasing in recent years. This biopolymer has particular properties that can improve cement performance, like high mechanical properties and thermal resistance. For this reason, and in light of the problems that carbonation may pose in the long term in the context of geological storage of CO2 studies were carried out under supercritical CO2 conditions analyzing the behavior of cement with nanocellulose additions.Rheological, mechanical, thermal, and microstructural tests were performed on samples with different percentages of BNC [1]. Subsequently, cylindrical specimens were subjected to supercritical CO2 conditions (20 MPa and 90 °C) with different percentages of nanocellulose using two curing methods, one long-term curing at low temperature [2] and one short-term curing at high temperature [3].These results showed that BNC produces an increase in slurry viscosity but retains a greater amount of water which aids in its subsequent hydration. This could be observed in its microstructure, where a greater amount of hydration products, a higher degree of hydration, and a decrease in porosity were observed. It is likely that this increase in hydration was the reason that cements with nanocellulose had a uniaxial compressive strength up to 20% higher than neat cement. It was also observed that higher BNC contents improve the thermo-mechanical behavior under oscillating bending stress. After carbonation, the microstructure shows that the capillary porosity decreases steadily to values of 5%, which reduces the penetration of carbonic acid into the sample. All cements showed a reduction in mechanical strength, but cements with BNC had a lower degree of carbonation and better mechanical behavior, because of the lower capillary porosity prior to carbonation (Figure 1). However, these effects were not observed when the cement was subjected to a curing process under unfavorable conditions at high temperatures. In this case, the large increase in porosity dulls the short-term hydration effects and the strength of cements with nanocellulose is lower prior to the carbonation process. After carbonation, a relative increase in the strength of the samples with BNC is higher, however, it is still below the strength of neat cement [4]. These experimental studies were simulated using a coupled chemo-hydro-mechanical model. The model simulates the carbonation front advance in cement subjected to supercritical CO2 and the changes generated by the chemical reactions using the classic balance equations of continuum mechanics relative to mass, momentum, entropy, and energy. Simultaneous dissolution of portlandite and C-S-H, dissolution of calcite, and a damage model were considered. The carbonation progress of the samples was represented and an extrapolation was made to an oil well based on the parameters obtained from the experiments and simulations.
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Siddiqui, Mohammad A. Q., Klaus Regenauer-Lieb, and Hamid Roshan. "Thermo-Hydro-Chemo-Mechanical (THCM) Continuum Modelling of Subsurface Rocks: A Focus On Thermodynamics-based Constitutive Models." Applied Mechanics Reviews, January 23, 2023, 1–62. http://dx.doi.org/10.1115/1.4056726.
Abstract:
Abstract Accurate multi-physics modelling is necessary to simulate and predict the long-term behaviour of subsurface porous rocks. Despite decades of modelling subsurface multi-physics processes in porous rocks, there are still considerable uncertainties and challenges remaining partly because of the way the constitutive equations describing such processes are derived (thermodynamically or phenomenologically) and treated (continuum or discrete) regardless of the way they are solved (e.g. finite-element or finite-volume methods). We review here continuum multi-physics models covering aspects of poromechanics, chemo-poromechanics, thermo-poromechanics, and thermo-chemo-poromechanics. We focus on models that are derived based on thermodynamics to signify the importance of such a basis and discuss the limitations of the phenomenological models and how thermodynamics-based modelling can overcome such limitations. The review highlights that the experimental determination of thermodynamics response coefficients (coupling or constitutive coefficients) and field applicability of the developed thermodynamics models are significant research gaps to be addressed. Verification and validation of the constitutive models, preferably through physical experiments, is yet to be comprehensively realized which is further discussed in this review. The review also shows the versatility of the multi-physics models to address issues from shale gas production to CO2 sequestration and energy storage and highlights the need for inclusion of thermodynamically consistent damage mechanics, coupling of chemical and mechanical damage and two-phase fluid flow in multi-physics models.