Résistance d'un polycristal avec interfaces intergranulaires imparfaites

Dormieux, Luc; Sanahuja, Julien; Maalej, Yamen

doi:10.1016/j.crme.2006.11.005

Cited by 24 publications

(22 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Still, in the maximally stressed bundle, not the (first-order) average phase stresses r hyd;u;J ; as introduced below (8), but stress peaks govern the failure of the (u,0)-oriented hydrate phase [61]. Such peaks can be appropriately estimated through quadratic stress averages over suitably chosen subdomains of the RVE sc , such as 3D subdomains (bulk phases) [4,38,49] or 2D interfaces [15,20]. We here introduce quadratic (or second-order) averages over (u,0)-oriented hydrates, averaged, in the sense of (4), over all hydrates oriented in one direction (u,0), max x2X hyd;u;J r dev ðx; u; JÞ % r dev hyd;u;J ¼ lim…”

Section: Upscaling Of Strength From Hydrate Level To Shotcrete Levelmentioning

confidence: 99%

From micron-sized needle-shaped hydrates to meter-sized shotcrete tunnel shells: micromechanical upscaling of stiffness and strength of hydrating shotcrete

2008

View full text Add to dashboard Cite

Knowledge on the stresses in shotcrete tunnel shells is of great importance, as to assess their safety against severe cracking or failure. Estimation of these stresses from 3D optical displacement measurements requires shotcrete material models, which may preferentially consider variations in the water-cement and aggregate-cement ratios. Therefore, we employ two representative volume elements within a continuum micromechanics framework: the first one relates to cement paste (with a spherical material phase representing cement clinker grains, needle-shaped hydrate phases with isotropically distributed spatial orientations, a spherical water phase, and a spherical air phase; all being in mutual contact), and the second one relates to shotcrete (with phases representing cement paste and aggregates, whereby aggregate inclusions are embedded into a matrix made up by cement paste). Elasticity homogenization follows selfconsistent schemes (at the cement paste level) and MoriTanaka estimates (at the shotcrete level), and stress peaks in the hydrates related to quasi-brittle material failure are estimated by second-order phase averages derived from the RVE-related elastic energy. The latter permits upscaling from the hydrate strength to the shotcrete strength. Experimental data from resonant frequency tests, ultrasonics tests, adiabatic tests, uniaxial compression tests, and nanoindentation tests suggest that shotcrete elasticity and strength can be reasonably predicted from mixture-and hydration-independent elastic properties of aggregates, clinker, hydrates, water, and air, and from strength properties of hydrates. At the structural level, the micromechanics model, when combined with 3D displacement measurements, predicts that a decrease of the water-cement ratio increases the safety of the shotcrete tunnel shell.

show abstract

Section: Upscaling Of Strength From Hydrate Level To Shotcrete Levelmentioning

confidence: 99%

From micron-sized needle-shaped hydrates to meter-sized shotcrete tunnel shells: micromechanical upscaling of stiffness and strength of hydrating shotcrete

2008

View full text Add to dashboard Cite

show abstract

“…For further use, the quadratic average of the tangential part of the stress vector acting at grain contacts of the non‐coated grains, excluding once again the interface between the grains and the porous phase, also needs to be calculated. As shown in , adapting to the case of a REV containing elastic interfaces a method presented in , this average

\sqrt{{\overset{T_{t}^{2}}{true}}^{Q}}

can be deduced by differentiation of the macroscopic energy:

\sqrt{{\overset{true¯}{T_{t}^{2}}}^{Q}} = \sqrt{\frac{\frac{\partial k^{hom}^{- 1}}{\partial {(R k_{italictQ})}^{- 1}} Σ_{m}^{2} + \frac{\partial g^{hom}^{- 1}}{\partial {(R k_{italictQ})}^{- 1}} Σ_{d}^{2}}{3 f_{Q} ((), f_{Q} + f_{C}) ((), 2 f_{Q} + 2 f_{C} - 1)}}

where

Σ_{d} = \sqrt{(Σ - Σ_{m} 1) : (Σ - Σ_{m} 1) / 2}

.…”

Section: Effective Friction Coefficient Of a Clayey Sand Gougementioning

confidence: 99%

Nonlinear homogenization approach to the friction coefficient of a quartz‐clay fault gouge

Barthélémy

Souque

Daniel

2012

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

SUMMARY This study aims at building a theoretical framework allowing for estimation of the macroscopic friction coefficient of a mixed quartz/clay fault gouge from the description of the microstructure and from relevant properties at the lower scale. The effect of clay content is particularly highlighted through two opposite morphology cases. The first one corresponds to a grain framework‐supported microstructure with a predominant content of quartz grains forming a connected structure and some clay filling the intergranular space. The second considered morphology corresponds to a clay matrix‐supported microstructure in which quartz grains are embedded. The friction coefficient of the gouge is derived with respect to the clay content for both morphologies because of theoretical homogenization techniques. The models prove to be in good agreement with experimental results from the literature. Copyright © 2012 John Wiley & Sons, Ltd.

show abstract

“…In turn, the non linear problem can be solved using secant or affine methods (Suquet, 1995(Suquet, , 1997 which rely on the solution to the associated linear problem. These methods proved successful to predict the strength of heterogeneous material, even in the presence of interface effects (Barth el emy, 2005; Barth el emy and Dormieux, 2004;Dormieux et al, 2010Dormieux et al, , 2006Dormieux et al, . 2007He et al, 2013;Maalej et al, 2009;Maghous et al, 2009;Sanahuja and Dormieux, 2005).…”

Section: Introductionmentioning

confidence: 96%

“…Such imperfect interfaces can be characterized by a criterion the stress vector acting on the interface must not exceed. Thanks to homogenization methods, the strength of granular geomaterials has been investigated, successively considering the cases of rigid grains interfaced by a Tresca criterion (Dormieux et al, 2007), a2 frictional criterion (Maalej et al, 2009) or a cohesive frictional criterion (He et al, 2013), as well as the competition between Tresca interfacial and Von Mises intragranular strength (Dormieux et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Strength of a matrix with elliptic criterion reinforced by rigid inclusions with imperfect interfaces

Bignonnet¹,

Dormieux²,

Lemarchand³

2015

European Journal of Mechanics - A/Solids

Self Cite

View full text Add to dashboard Cite

International audienceElliptic effective strength criteria in the mean-deviatoric stress plane are encountered in porous media for a granular material made of rigid grains with cohesive frictional interfaces or a material with pores in a Drucker-Prager matrix. The macroscopic strength criterion of a heterogeneous material comprising a matrix with elliptic strength criterion reinforced by rigid inclusions with perfect or imperfect interfaces is studied. Considered imperfect interfaces follow either a Tresca or a Mohr-Coulomb strength criterion. Derived macroscopic criteria are shown to be a combination of a larger ellipse, which corresponds to the criterion for perfectly bounded interfaces, conditionally truncated by a smaller ellipse resulting from the activation of interfacial mechanisms. The activation of the interfacial mechanisms depends on the matrix and interfaces strength properties, inclusions concentration, as well as the macroscopic strain triaxiality ratio

show abstract

Résistance d'un polycristal avec interfaces intergranulaires imparfaites

Cited by 24 publications

References 10 publications

From micron-sized needle-shaped hydrates to meter-sized shotcrete tunnel shells: micromechanical upscaling of stiffness and strength of hydrating shotcrete

From micron-sized needle-shaped hydrates to meter-sized shotcrete tunnel shells: micromechanical upscaling of stiffness and strength of hydrating shotcrete

Nonlinear homogenization approach to the friction coefficient of a quartz‐clay fault gouge

Strength of a matrix with elliptic criterion reinforced by rigid inclusions with imperfect interfaces

Contact Info

Product

Resources

About