Publications

2002

• La mécanique des matériaux: échelles que j'aime...
  
  • Zaoui A.
  , 2002. No abstract provided
• Identification of a viscoplastic material behaviour under anisothermal conditions
  
  • Constantinescu Andrei
  • Verger Loick
  , 2002, pp.221-228.
• Post-buckling of an elastic plate over an inviscid and buoyant fluid
  
  • Leroy Yves
  • Guiton Martin
  • Triantafyllidis Nicolas
  International Journal of Solids and Structures, Elsevier, 2002, 39, pp.3873-3891. The model problem proposed to study the buckling of stratified geological layers consists of a linearly elastic plate, capable of accommodating finite rotations, resting over an inviscid and buoyant fluid. The Lyapunov–Schmidt–Koiter decomposition is applied to construct the bifurcated equilibrium solutions. The asymptotic analysis of the post-buckling reveals a decrease in the magnitude of the lateral compressive force during an overall shortening of the stratified structure. Buckling and post-buckling are not influenced by the presence of a vertical stress gradient in the elastic plate. (10.1016/S0020-7683(02)00185-3)
  DOI : 10.1016/S0020-7683(02)00185-3
• The influence of confinement on the bearing capacity of strip footings
  
  • Salençon Jean
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2002, 330, pp.319-326. The bearing capacity for a strip footing acting on a soil foundation with rigid boundaries at a finite distance is investigated within the framework of the Yield design theory both for a purely cohesive soil and for a frictional soil. It is shown that the analysis can be performed simply by referring to already existing results concerning the bearing capacity of a strip footing on a soil layer with limited thickness. Each bearing capacity factor in Terzaghi formula is increased by a factor that increases when the distance of the rigid boundary to the edge of the footing decreases. The bearing capacity is proved to be the more sensitive to this confining effect as the friction angle of the soil increases. From a physical point of view this theoretical analysis would show that, when effective, confinement reduces the depth of the soil layer involved in the collapse mechanism. (10.1016/S1631-0721(02)01459-6)
  DOI : 10.1016/S1631-0721(02)01459-6
• Confining effect on the bearing capacity of circular footings on a purely cohesive soil
  
  • Salençon Jean
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2002, 330, pp.521-525. The bearing capacity of axially symmetrical footings acting on a purely cohesive soil foundation contained by a rigid wall at a finite distance is investigated within the framework of the Yield design theory. Following the same tracks as in a preceding paper devoted to strip footings, the analysis is performed by referring to already existing results concerning the bearing capacity of a circular footing on a soil layer with limited thickness. It comes out that the bearing capacity factor determined by Eason and Shield for a rough circular footing on an unlimited soil foundation is increased by a correction factor that increases when the diameter of the container decreases. Comparison with the results obtained for strip footings acting on a purely cohesive soil in the same conditions shows that the confining effect is significantly lower for a circular footing than for a strip footing. (10.1016/S1631-0721(02)01495-X)
  DOI : 10.1016/S1631-0721(02)01495-X
• A novel inverse problems in emission imaging
  
  • Nguyen Mai K.
  • Truong T.T.
  • Bui Huy Duong
  , 2002. No abstract provided
• A 3D Micromechanical analysis of Stage I fatigue crack growth in reversed torsion
  
  • Doquet V.
  • Mignot F.
  • Frelat J.
  , 2002, pp.2673-2680. No abstract provided
• De l'Elasto-plasticité au Calcul à la rupture
  
  • Salençon Jean
  , 2002, pp.264. Cet ouvrage est une introduction à l'élasto-plasticité et au calcul à la rupture pour leurs applications à l'analyse du comportement des systèmes mécaniques, des structures et des ouvrages. Le comportement élasto-plastique y est d'abord présenté pour le milieu continu tridimensionnel dans le contexte de la transformation infinitésimale et de la règle d'écoulement plastique " associée ". Ce modèle est ensuite étendu aux milieux continus généralisés. En se plaçant dans le cadre d'hypothèses des petites perturbations, le comportement global d'un système constitué d'un tel matériau élasto-plastique soumis à un processus de chargement quasi-statique, exprimé en fonction des paramètres de chargement, répond au modèle élasto-plastique. L'écrouissage du système est dû à la fois à l'écrouissage propre du matériau et aux contraintes et déformations résiduelles engendrées par l'incompatibilité géométrique des déformations plastiques. (Afin de conserver à l'ouvrage la concision d'une introduction, on s'est ici abstenu de tout développement relatif aux méthodes employées dans les logiciels de résolution ou aux théorèmes d'adaptation). En l'absence d'écrouissage propre du matériau constitutif on met en évidence les chargements limites de ruine plastique du système. La théorie du calcul à la rupture élargit ce point de vue en considérant un système dont le matériau constitutif a des capacités de résistance limitées physiquement ou réglementairement. Les chargements extrêmes sont définis par la compatibilité de l'équilibre du système et de la résistance du matériau. Des théorèmes variationnels permettent de les déterminer. Cette théorie générale montre l'unité, souvent occultée par leurs présentations disjointes, des diverses méthodes mises en œuvre dans la pratique pour les milieux continus tridimensionnels ou bidimensionnels, pour les poutres, les plaques, etc. exposées dans de nombreux traités classiques. La pertinence pratique de l'approche par le calcul à la rupture du point de vue des applications dépend du phénomène physique qui limite la résistance ; cela est notamment pris en compte dans l'approche réglementaire de la sécurité aux états limites ultimes dont la théorie du calcul à la rupture constitue le socle fondamental.
• Underground storage regulations in France
  
  • Bérest P.
  , 2002, pp.1-13. No abstract provided
• Etude micromécanique de la disparition du seuil de fissuration par fatigue dans un alliage de titane biphasé
  
  • Mignot F.
  • Doquet V.
  • Sarrazin-Baudoux C.
  • Petit J.
  , 2002. No abstract provided
• Une formulation symétrique pour le couplage éléments finis - éléments de frontière en mécanique.
  
  • Mouhoubi Saida
  • Bonnet Marc
  • Ulmet Laurent
  Revue Européenne des Éléments Finis, HERMÈS / LAVOISIER, 2002, 11, pp.277-289. Cet article présente une procédure, basée sur les équations intégrales variationnelles symétriques régularisées en élasticité tridimensionnelle, permettant de construire la matrice de rigidité d'un super-élément. Celle-ci ne porte que sur les déplacements nodaux à la frontière du domaine définissant le super-élément, supposé élastique et sans force de volume. Cette technique a été implantée dans l'environnement CAST3M, y compris dans le cas où le domaine élastique contient une fissure. Trois exemples numériques tridimensionnels sont présentés: cavité sphérique pressurisée en milieu infini élastoplastique, assemblage, cylindre avec fissure. (10.3166/reef.11.277-289)
  DOI : 10.3166/reef.11.277-289
• Définition de la perméabilité équivalente des massifs fracturés par des méthodes d'homogénéisation
  
  • Pouya Ahmad
  • Alexis Courtois
  Comptes Rendus de l'Académie des Sciences - Series III - Sciences de la Vie, Elsevier, 2002, 334, pp.975-979. In the methods used for determination of the hydraulic behaviour at large scale of fractured rock masses, based on the simulation of flow in a fracture network, the mean flux and mean pressure gradient in the network are not rigorously determined. A method is given for deriving these quantities, in a heterogeneous permeable block, from pressure and flux values on the boundary of the block. A block conductivity tensor is then defined based on the condition of linear variation of the pressure on the boundary of the block. It is shown that this conductivity tensor is symmetric and positive definite. An example of application to a model of fractured medium is given. (10.1016/S1631-0713(02)01839-4)
  DOI : 10.1016/S1631-0713(02)01839-4
• Performance parasismique des structures en béton armé
  
  • Luong M. P.
  , 2002. No abstract provided
• Utilisation des ensembles flous pour les calculs en géotechnique
  
  • Maïolino S.
  • Faure R.-M.
  , 2002. No abstract provided
• Tribological and corrosion wear of graphite ring against Ti6Al4V disk in artificial sea water
  
  • Serre I.
  • Celati N.
  • Pradeilles-Duval R. M.
  Wear, Elsevier, 2002, 252, pp.711-718. Severe degradations result from the friction of two antagonists in sea water environment. It is proposed to evaluate materials resistance to wear with a tribocorrosion experimental set-up which is mechanically and electrochemically instrumented. The method is illustrated with graphite and Ti6Al4V. The deposition of graphite on Ti6Al4V samples is observed and modifies the contact characteristics. Processes of graphite wear due to mechanical effect are characterised. Observations clearly indicate that Ti6Al4V degradations depend on the electrochemical potential imposed and more precisely on the electrochemical conditions in the contact zone. (10.1016/S0043-1648(02)00030-3)
  DOI : 10.1016/S0043-1648(02)00030-3
• Continuum micromechanics: survey
  
  • Zaoui André
  Journal of Engineering Mechanics - ASCE, American Society of Civil Engineers, 2002, 128 (8), pp.808-816. The foundations of classical homogenization techniques, which aim at predicting the overall behavior of heterogeneous materials from that of their constituents, are reviewed. After introductory definitions and a methodological preamble, attention is focused on linear elasticity, for which the basic principles of estimating and bounding the overall properties are introduced and illustrated. In this context, special recourse is made for that to the solution of the inclusion and inhomogeneity problems as reported by Eshelby in 1957. Approaches proposed recently to account in a better way for the structural morphology of the considered materials are briefly mentioned. The case of linear elasticity with eigenstrains is then discussed: several applications, including heterogeneous thermoelasticity, can be investigated within this framework. Finally, outlines of nonlinear micromechanics are briefly reported from a historical point of view: from rate-independent elastoplasticity to nonlinear elasticity and viscoplasticity, examples of a fruitful interaction between the search for new estimates and the derivation of rigorous bounds are given and the crucial question of the description of intraphase heterogeneity is emphasized. Viscoelastic coupling and rate-dependent effects are briefly discussed in conclusion. (10.1061/(ASCE)0733-9399(2002)128:8(808))
  DOI : 10.1061/(ASCE)0733-9399(2002)128:8(808)
• Analyse expérimentale des longueurs caractéristiques d'interaction
  
  • Doumalin P.
  • Bornert Michel
  • Crépin Jérôme
  , 2002. No abstract provided
• Une méthode de calcul de structures soumises a des chargements mobiles
  
  • Nguyen-Tajan Mac-Lan
  • Maitournam Habibou
  • Thomas Jean Jacques
  Revue Européenne des Éléments Finis, HERMÈS / LAVOISIER, 2002, 11, pp.247-261. Le travail présenté dans cet article s'inscrit dans une étude globale de la tenue en service d'un disque de frein automobile. Celui-ci subit des chargements thermomécaniques responsables de divers types d'endommagement : faïençage, fissures radiales sur les pistes de frottement, rupture du bol. La prédiction numérique de ces avaries exige d'abord la mise au point de méthodes numériques adaptées aux problèmes de structures soumises à des chargements thermomécaniques mobiles. Celles-ci consistent en des algorithmes eulériens qui sont présentés et décrits. (10.3166/reef.11.247-261)
  DOI : 10.3166/reef.11.247-261
• A micromechanical model for the TiAl lamellar grain
  
  • Gélébart Lionel
  • Bornert Michel
  • Crépin Jérôme
  • Bretheau Thierry
  , 2002.
• Crack shape sensitivity by the adjoint variable method using a boundary-only formula
  
  • Rus Carlborg G.
  • Bonnet Marc
  • Gallego Roberto
  , 2002. No abstract provided
• A new viscoelastic law used for thermomechanical analysis in the automotive industry
  
  • Verger Loick
  • Constantinescu Andrei
  • Pommier Benjamin
  , 2002.
• Approche expérimentale et modélisation micromécanique du comportement des matériaux
  
  • Equipe Micromécanique Xx
  , 2002.
• Computational basis for elastodynamic identification in a semi-infinite solid
  
  • Nintcheu Fata S.
  • Guzina B. B.
  • Bonnet Marc
  , 2002. No abstract provided
• Nondestructive evaluation of material instability of a deep argillaceous rock
  
  • Luong M. P.
  • Eytard J. C.
  , 2002, pp.67-76. No abstract provided
• Sensitivity analysis for shape perturbation of cavity or internal crack using BIE and adjoint variable approach
  
  • Bonnet Marc
  • Burczynski T.
  • Nowakowski M.
  International Journal of Solids and Structures, Elsevier, 2002, 39, pp.2365-2385. This paper deals with the application of the adjoint variable approach to sensitivity analysis of objective functions used for defect detection from knowledge of supplementary boundary data, in connection with the use of BIE/BEM formulations for the relevant forward problem. The main objective is to establish expressions for crack shape sensitivity, based on the adjoint variable approach, that are suitable for BEM implementation. In order to do so, it is useful to consider first the case of a cavity defect, for which such boundary-only sensitivity expressions are obtained for general initial geometry and shape perturbations. The analysis made in the cavity defect case is then seen to break down in the limiting case of a crack. However, a closer analysis reveals that sensitivity formulas suitable for BEM implementation can still be established. First, particular sensitivity formulas are obtained for special shape transformations (translation, rotation or expansion of the crack) for either two- or three-dimensional geometries which, except for the case of crack expansion together with dynamical governing equations, are made only of surface integrals (three-dimensional geometries) or line integrals (two-dimensional geometries). Next, arbitrary shape transformations are accommodated by using an additive decomposition of the transformation velocity over a tubular neighbourhood of the crack front, which leads to sensitivity formulas. This leads to sensitivity formulas involving integrals on the crack, the tubular neighbourhood and its boundary. Finally, the limiting case of the latter results when the tubular neighbourhood shrinks around the crack front is shown to yield a sensitivity formula involving the stress intensity factors of both the forward and the adjoint solutions. Classical path-independent integrals are recovered as special cases. The main exposition is done in connection with the scalar transient wave equation. The results are then extended to the linear time-domain elastodynamics framework. Linear static governing equations are contained as obvious special cases. Numerical results for crack shape sensitivity computation are presented for two-dimensional time-domain elastodynamics. (10.1016/S0020-7683(02)00131-2)
  DOI : 10.1016/S0020-7683(02)00131-2