Publications

2001

• Modelling rate-dependent effects in heterogeneous materials
  
  • Masson Renaud
  • Zaoui André
  , 2001.
• Influence of the test frequency and environment on mode II fatigue crack growth in a maraging steel
  
  • Doquet Véronique
  , 2001.
• Identification of constitutive parameters in engineering problems
  
  • Constantinescu Andrei
  • Lecampion Brice
  • Verger Laetitia
  • Tardieu Nicolas
  , 2001.
• Wear modelling of contact plan/plan between graphite and titanium alloy
  
  • Serre Ingrid
  • Bonnet Marc
  • Celati N.
  • Duval Rachel-Marie Pradeilles
  , 2001, pp.287-293.
• Nondestructive evaluation of rock material instability
  
  • Luong M. P.
  , 2001, pp.463-466. No abstract provided
• Increasing the maximum strain measured with elastic and viscoelastic bars
  
  • Ohtman Ramzi
  • Bussac Marie-Noëlle
  • Collet Pierre
  • Gary Gérard
  , 2001, pp.49-56. A new method has been developed for separating dispersive waves in elastic and viscoelastic rods from multi-point strain and velocity measurements. Knowing then the basic waves, the stress, the strain, the displacement and the particle velocity can be calculated at any point of the bar. The method is based on the assumption of one dimensional and single mode dispersive wave propagation and it takes account of the wave dispersion. It is shown that the method is stable with respect to noise, so that the measuring time is increased considerably. Subsequently, the maximum strain which can be measured in a material tested with a classical SHPB (Split Hopkinson Pressure Bar) set-up is also increased and is no longer limited by the length of the bars. The method is illustrated here by applying it successfully to the analysis of a real test of aluminum honeycomb. It can also be applied to other kinds of one-dimensional and single-mode dispersive waves such as flexural waves in beams and acoustic waves in wave-guides.
• Infrared observation of the mechanical performance of tennis strings
  
  • Luong M. P.
  , 2001, pp.624-635. No abstract provided
• Comportement mécanique non linéaire et homogénéisation
  
  • Bornert Michel
  , 2001.
• Fatigue Analysis of Welded Structures during Random Loadings
  
  • Zarka Joseph
  • Karaouni Habib
  , 2001.
• A Salt-cavern abandonment test
  
  • Bérest Pierre
  • Bergues Jean
  • Brouard Benoît
  • Durup Gerard
  • Guerber Benoît
  International Journal of Rock Mechanics and Mining Sciences, Pergamon and Elsevier, 2001, 38 (3), pp.357-368. Thousands of caverns have been leached out from deep salt formations. They are used for saturated brine production and/or hydrocarbons storage. They will be abandoned some day: the access well will be plugged with cement, isolating a large bubble of saturated brine. The later evolution of such a bubble raises serious concerns for environmental protection; salt creep and brine thermal expansion can lead to brine pressure build-up and rock-mass fracture, then brine seepage can lead to pollution of overlying water-bearing strata. Taking into account salt formation permeability leads to less pessimistic scenarios. An 18-month test has been performed on a deep brine-filled cavern. The objective was to measure the brine equilibrium pressure reached when the cavern is closed. Such an equilibrium is reached when salt mass creep, which leads to cavern shrinkage, balances brine permeation through the cavern wall. This objective was met by imposing different pressure levels and observing whether the pressure increased (or decreased) with respect to time. Data misinterpretation (i.e., a well leak instead of a cavern-proper leak) was precluded by a special monitoring system. The observed equilibrium pressure was significantly smaller than geostatic pressure, alleviating any fracture risk for a sealed and abandoned cavern in this salt formation. (10.1016/S1365-1609(01)00004-1)
  DOI : 10.1016/S1365-1609(01)00004-1
• Homogénéisation des milieux aléatoires : bornes et estimations
  
  • Bornert Michel
  • Bretheau Thierry
  • Gilormini Pierre
  , 2001, pp.133-222.
• Stability of a quasi-static evolution of a visco-elastic, visco-plastic or elastic-plastic solid
  
  • Abed-Meraim Farid
  • Nguyen Quoc Son
  , 2001, pp.1-14. The problem of stability of a quasi-static evolution of a solid is discussed in the framework of standard plasticity and visco-plasticity. General results concerning the criterion of second variation of energy are presented. Two different approaches are considered to discuss this problem for visco-elastic, visco-plastic or elastic-plastic solids. The first approach is based upon the linearization method and gives the asymptotic stability of the evolution of a visco-elastic solid when the associated dissipation potential is quadratic and positive-definite. The second approach introduces a direct analysis of the evolution in a nonsmooth but convex framework of plasticity and visco-plasticity. (10.1007/978-1-4613-0275-9_1)
  DOI : 10.1007/978-1-4613-0275-9_1
• Approche par contrôle optimal des structures élastoviscoplastiques sous chargement cyclique
  
  • Peigney Michaël
  • Stolz Claude
  Comptes Rendus de l'Academie des Sciences Serie II, Gauthier-Villars, 2001, 329, pp.643-648. On utilise l'approche par contrôle optimal pour étudier le comportement de structures élastoplastiques sous chargement cyclique. L'état asymptotique est ainsi obtenu comme solution d'un problème approché cohérent avec une discrétisation spatiale. Dans ce cadre, on montre que les seuls points stationnaires de la fonctionnelle à minimiser sont les minima globaux. (10.1016/S1620-7742(01)01381-2)
  DOI : 10.1016/S1620-7742(01)01381-2
• Action d'une conduite circulaire sur un sol cohérent
  
  • Salençon Jean
  , 2001, 2001-08-31, pp.1311-1314. On s'intéresse à la détermination théorique de la capacité portante d'un sol homogène, isotrope, purement cohérent sur lequel repose une conduite circulaire. Les deux conditions extrêmes de contact à l'interface entre la conduite et le sol (interface lisse sans résistance à la traction et interface totalement adhérente) sont envisagées ce qui permet d'encadrer la solution du problème réel. On a appliqué les méthodes d'approche par l'intérieur statique et d'approche par l'extérieur cinématique de la théorie du calcul à la rupture pour une analyse paramétrique en fonction de la profondeur d'enfoncement de la conduite. Les évaluations par défaut et par excès ainsi obtenues montrent que l'effet de la gravité est purement additif, égal à la simple «poussée d'Archimède» exercée par le sol et améliorent, dans le cas de l'interface lisse, les résultats antérieurs de Mur1l: Wagner & Randolph.
• On the behaviour characterisation of polymeric foams over a large range of strain rates
  
  • Zhao Han
  • Gary Gérard
  , 2001, pp.23-28. The testing and modelling of the mechanical behaviour of some polymeric foams involved in the automotive industry are presented. A variety of current experimental arrangements over a large range of strain rates have been reviewed. Recent improvements of a particularly useful technique for impact loading–the split Hopkinson bar–are presented. A phenomenological model is developed to describe experimental data. Difficulties for 3-dimensional testing and modelling are also discussed.
• Etude de systèmes avec surfaces de discontinuités mobiles sous chargement thermomécanique
  
  • Peigney Michaël
  • Stolz C.
  , 2001. No abstract provided
• Study of the creep behavior of a possible host clayey rock
  
  • Gasc-Barbier M.
  • Chanchole S.
  • Lecampion B.
  • Bérest P.
  • Hoteit N.
  , 2001. No abstract provided
• Fatigue Analysis during One-parametered Loadings
  
  • Zarka Joseph
  • Karaouni Habib
  , 2001.
• Effet de la fréquence et de l'environnement sur la propagation des fissures de fatigue en mode II dans un acier maraging
  
  • Doquet V.
  , 2001. No abstract provided
• Un outil de la mécanique des matériaux : la micro-extensométrie
  
  • Bretheau Thierry
  • Crépin Jérôme
  • Doumalin Pascal
  • Bornert Michel
  , 2001.
• Application du principe du maximum de vraisemblance à la séparation des ondes dans les barres
  
  • Othman Ramzi
  • Bussac Marie-Noëlle
  • Collet Pierre
  • Gary Gérard
  , 2001.
• Techniques of Infrared Thermography
  
  • Luong M. P.
  , 2001, pp.342-357.
• Application du contrôle optimal à l'identification d'un chargement thermique
  
  • Delattre Benoît
  • Ivaldi Damien
  • Stolz Claude
  , 2001, 11 (2-4), pp.165-172. La détermination du champ de température sur certaines pièces d'un moteur est obtenue par la résolution d'un problème inverse. Une alternative aux méthodes expérimentales coûteuses utilisées aujourd'hui est la méthode du contrôle optimal qui permet d'estimer le champ de température à partir de quantités mesurées sur pièce. Différents tests préfigurent des possibilités de prédiction et de fiabilité de la méthode. (10.3166/reef.11.393-404)
  DOI : 10.3166/reef.11.393-404
• Solid-fluid phase transformation within grain boundaries during compaction by pressure solution
  
  • Ghoussoub Joumana
  • Leroy Yves
  Journal of the Mechanics and Physics of Solids, Elsevier, 2001, 49 (10), pp.2385-2430. The overall compaction of porous rocks due to intergranular pressure solution (IPS) results from the dissolution of minerals within contact regions and the diffusive transport through the grain boundary of the dissolved species towards the fluid-filled pore space. The grain boundary structure can be imagined to be composed of dry contact zones, thin fluid films and fluid-filled cavities. The connectiveness and tortuosity of this structure determine the effective diffusivity of grain contacts and thus the potential of porous rock to compact by the action of IPS. The evolution in time of the grain-boundary structure, and thus of the effective diffusivity, is discussed here with the help of two 2D initial- and boundary-value problems which are solved by analytical and numerical means. The evolution of the solid–fluid interfaces within the grain boundary is governed by a phase transformation between the non-hydrostatically stressed elastic solid and the trapped fluid assumed in mechanical equilibrium. The characteristic time is provided by a linear kinetic law. The evolution of the structure away from a state of thermodynamic equilibrium during a loading normal to the grain boundary is found to occur in two steps. The first one consists of a diffuse morphology evolution in time and results in an enhancement of any initial stress concentration. The second step is characterized by a rapid and localized dissolution in the region of stress concentration. The latency period prior to localization is governed by the magnitude of the non-hydrostatic remote stress as well as the microstructural geometric factor responsible for the initial stress concentration at the solid–fluid interface. The localized dissolution is shown to provide a mechanism for the fluid to penetrate a previously dry contact region by marginal dissolution and thus to create a fluid film. However, the newly formed thin fluid layer is found to be unstable pointing to a possible repeated reorganization or dynamic evolution of the grain boundary internal structure during the action of IPS. (10.1016/S0022-5096(01)00012-6)
  DOI : 10.1016/S0022-5096(01)00012-6
• Affaissement en surface lors du creusement d'un souterrain
  
  • Bérest Pierre
  • Ghoreychi Mehdi
  • Habib Pierre
  Revue française de Géotechnique, edp sciences, 2001, 92, pp.41-47. L’affaissement à long terme de la surface du sol au-dessus d’un tunnel est comparé à l’affaissement instantané au moment du creusement dans le cadre de l’élasticité linéaire. Les résultats numériques montrent, sur des exemples vraisemblables, que si des déplacements importants sont décelés en surface, il s’agit très probablement de déformations irréversibles. (10.1051/geotech/2000092041)
  DOI : 10.1051/geotech/2000092041