Publications

2000

• Identification d'une distribution axisymétrique de contraintes de contact élastique
  
  • Ben Abdallah Jallel
  • Bonnet Marc
  , 2000.
• Tenue d'ancrages LMS sur fonds coralliens indurés
  
  • Luong Minh-Phong
  • Habib Pierre
  Rev. Franç. Géotech., 2000, 89, pp.29-32. Cet article rapporte une expérimentation en vraie grandeur d’un système d’ancrage LMS à forte capacité de tenue dans un fond marin constitué de calcaires coralliens indurés de la Polynésie française. Les résultats ont mis en évidence la possibilité de reprise des efforts dans des zones où la compacité du terrain exclut la mise en œuvre des ancres marines traditionnelles. La sécurité de tenue ne dépend pratiquement pas de la couche superficielle souvent hétérogène. La reprise des efforts verticaux réduit très sensiblement la longueur des lignes de mouillage. Le poids réduit de l’ancrage, grâce à une efficacité exceptionnelle (> 100), est un avantage technique et économique de mise en œuvre, extrêmement appréciable par rapport aux ancres marines de type classique. (10.1051/geotech/1999089029)
  DOI : 10.1051/geotech/1999089029
• Stability Analysis of Incipient Folding and Faulting of an Elasto-Plastic Layer on a Viscous Substratum
  
  • Leroy Yves
  • Triantafyllidis Nicolas
  , 2000, pp.109-139. The initiation of two modes of instability, viz. folding and faulting, is investigated theoretically for an elasto-plastic, frictional- cohesive layer which is underlain by a viscous substratum. The destabilizing factors that are allowed to come into play are the tectonic stress, buoyancy forces resulting from a gravitationally unstable density stratification, and the redistribution of material at the top surface by erosion and deposition processes. The bending stiffness of the overburden, a non-linear function of stress, has a stabilizing influence. A variational formulation of the stability problem allows one to detect the onset of global modes of instability, such as folds and surface modes for compression as well as neck-type modes for extension. Predictions of these global modes remain valid as long as the local condition of strong ellipticity is satisfied. Failure of this condition marks the onset of discontinuities in the velocity field, which are characteristic of localized faulting. The sensitivity of these predictions to the assumed behaviour of the overburden and substratum materials is explored for a prototype representative of a dip section through the Campos salt basin on the Brazilian continental margin. These results illustrate the importance of a proper selection of analogue materials for the design of physical laboratory models. This point is underscored by employing a deformation theory of plasticity which could be seen to reproduce in a simple manner the accommodation of bulk deformation by slip along a population of pervasive small faults in sedimentary rocks as well as in analogue materials, such as sands, used in the laboratory. A historical account of the use of deformation theories of plasticity in stability analyses and a derivation of the relevant incremental moduli are also given in this paper. (10.1007/978-3-642-59617-9_6)
  DOI : 10.1007/978-3-642-59617-9_6
• Low cycle fatigue behaviour of β treated zirconium: partial irreversibility of twinning and consequences for damage
  
  • Crépin Jérôme
  • Bretheau Thierry
  • Caldemaison Daniel
  • Ferrer Franck
  Acta Materialia, Elsevier, 2000, 48, pp.505-516. The aim of this study is to understand the low cycle fatigue behaviour of β treated zirconium. It focuses especially on the contribution of twinning mechanisms. In situ fatigue tests performed inside a scanning electron microscope allow the observation of the activation of twins and their partial reversibility, depending on the applied stress. Moreover, the acoustic signature (shape factor) of the different twinning systems has been characterized allowing the following of inception and evolution of twins during the fatigue tests. Finally, the consequence of such a partial irreversibility on damage and crack localization is shown. (10.1016/S1359-6454(99)00358-4)
  DOI : 10.1016/S1359-6454(99)00358-4
• Modeling of the thermomechanical behaviour of a 7xxx aluminum alloy in welding conditions
  
  • Aubert S.
  • Archambault P.
  • Stolz Claude
  • Petitpas E.
  , 2000.
• Modèles micromécaniques de l'interface d'un système tribologique dans une approche thermodynamique de l'usure continue
  
  • Dragon-Louiset Marta
  Mechanics & Industry, EDP Sciences, 2000, 1 (1), pp.37-42. Cette étude s'inscrit dans une approche énergétique de l'usure de glissement proposant un modèle prédictif du phénomène. Concernant l'interface de deux corps soumis au contact et au frottement, elle cherche à caractériser un comportement moyen et homogénéisé du milieu granulaire, appelé troisième corps. Dans ce cadre, la description de ce milieu comme étant celle d'un fluide visqueux est proposée. On fait l'inventaire de lois de variation de la viscosité d'une suspension avec la fraction volumique des particules qu'elle contient, utilisables dans l'étude du troisième corps.
• Analyzing Relational Learning in the Phase Transition Framework
  
  • Giordana Attilio
  • Saitta Lorenza
  • Sebag Michèle
  • Botta Marco
  , 2000, pp.311-318. A key step of relational learning is testing whether a candidate hypothesis covers a given example. The covering test is equivalent to a Constraint Satisfaction Problem (CSP), which shows a phase transition in correspondence of critical values of some order parameters. This paper investigates the effects of the phase transition in the covering test on the complexity and feasibility of learning in first order logic languages. Several hundreds of artificial learning problems have been generated. FOIL and other learners have been applied to these problems. The experiments show the presence of a failure region, where all considered learners systematically fail to identify the target concept. Furthermore, the phase transition region behaves as an attractor for the learning search, whatever the target concept and the search strategy be. Interpretations of these findings are proposed and discussed.
• Standard dissipative systems and stability analysis
  
  • Nguyen Quoc Son
  , 2000, pp.343-354. Stability and bifurcation analyses are discussed here for time-independent standard dissipative systems of materials and structures. This discussion is illustrated by some simple applications in plasticity and fracture mechanics. (10.1007/0-306-46946-4_26)
  DOI : 10.1007/0-306-46946-4_26
• Thermodynamical description of moving discontinuities : applications to fracture and wear
  
  • Stolz C.
  , 2000. No abstract provided
• Simulation of hard particle impact on a TI-6Al-4V substrate coated by a tungsten film
  
  • Graff G.
  • Stolz C.
  • Pradeilles Duval R. M.
  • Sainte Catherine M.-C.
  , 2000. No abstract provided
• On Prandl's lifting equation arising in wear mechanics
  
  • Dragon-Louiset Marta
  • Bui Hui Duong
  • Stolz Claude
  Archives of Mechanics, 2000, 52 (4-5), pp.547-567. A sliding wear contact between a rigid punch and an elastic half plane in presence of a thin aggregate film composed of solid debris and a lubricant fluid is studied. The model based on any wear criterion and constitutive law of the film suggested by micromechnanics approximations. The mechanical system is governed by the evolution of the volume fraction of debris, considered as an internal state variable. The key step iterative computations for solving the non linear system of equations is based on the solution of the fundamental integro-differential equation for the compressive normal stress. Uniqueness of the solution of the integrodifferential equation is then proved. It is shown that there is a profound relationship between the latter equation and Prand'l lifting equation in aerodynamics : both equations cn be solved by Chebyshev's series, and experimentally by similar elaectrical setups. Mathematically, it is found that both equations are related to real and imaginary components of some complex potential, respectively, and to weakly adjoint integro-differential oprators.
• An elasto-plastic modelling for lamellar crystalline materials
  
  • Gélébart L.
  • Bretheau T.
  • Crépin Jérôme
  • Bornert Michel
  , 2000. No abstract provided
• Influence of thickness on crystallographic and mechanical properties of PVD tungsten coatings
  
  • Ganne T.
  • Crépin Jérôme
  • Zaoui A.
  • Pradeilles-Duval R. M.
  , 2000, pp.413-418. No abstract provided
• Mathematical Aspects of Boundary Element Methods
  
  • Bonnet Marc
  , 2000. (10.1201/9780429332449)
  DOI : 10.1201/9780429332449
• La bonne tension des cordes
  
  • Luong Minh-Phong
  Revue européenne des textiles à usages techniques, sports et loisirs, 2000, 36, pp.48-50.
• Intelligent numerical simulations in engineering problems
  
  • Zarka J.
  , 2000.
• Dynamic tensile testing of sheet metal
  
  • Mouro Pierre
  • Gary Gérard
  • Zhao Han
  Journal de Physique IV Proceedings, EDP Sciences, 2000, 10, pp.149-153. The testing of sheet metal at high strain rates requires the use of the SHPB set-up. This technique provides satisfactory results as far as the compression and shear are concerned. A modified SHPB set-up is presented here, which extends the scope of this technique to the tensile loading of sheet metals. In this case, many measurement problems arise due to the way in which the specimen is connected to the bars, which never completely prevents unexpected slipping and is liable to induce interference waves due to an impedance mismatch. The technique described here was based on the "hat specimen" technique proposed by Lindholm [l]. A two-dimensional "hat shaped" specimen is subjected to compression loading. A tensile state is induced in a symmetrically necked area, where higher strains are concentrated. Connecting supports of an appropriate shape are attached to the bars. They have the same impedance as that of the bars to avoid the occurrence of any interference waves. The "hat" shape prevents sliding, and to ensure perfect initial contact conditions, the complete system is elastically pre-stressed. A special method of wave analysis is then used to determine the forces and displacements occurring at the specimen ends from the strain signals recorded in the bars. (10.1051/jp4:2000925)
  DOI : 10.1051/jp4:2000925
• An example of stick-slip waves
  
  • Moirot Franck
  • Son Nguyen Quoc
  Comptes Rendus de l'Academie des Sciences Serie II, Gauthier-Villars, 2000, 328, pp.663-669. An analytical solution representing a family of stick-slip waves is obtained in a simple example modeling the dynamic behaviour of an elastic tube in contact with Coulomb friction with a rigid rotating cylinder. This family of waves represents the auto-excited periodic responses of the system. (10.1016/S1620-7742(00)01238-1)
  DOI : 10.1016/S1620-7742(00)01238-1
• On a new methodology for quantitative modeling of fretting fatigue
  
  • Dang Van Ky
  • Maitournam Habibou
  , 2000, pp.538-552. A new intrinsic methodology for the prediction of fretting fatigue failure of a structure is presented. It is based, first, on the evaluation of local relevant thermomechanical parameters by new thermoelastoplastic computational methods (direct cyclic method) and, second, on the systematic use of the Dang Van multiaxial high-cycle fatigue criterion. For the validation of this proposal, numerical simulations of fretting fatigue tests on a particular experimental setup considered as a structure are performed. The resulting prediction of the experimental fretting fatigue map in relation to plastic and fatigue material properties is good. (10.1520/STP14753S)
  DOI : 10.1520/STP14753S
• Science et règlement
  
  • Salençon Jean
  , 2000, pp.213-221.
• A critical study of SHPB test on the materials involved in crash problems
  
  • Zhao H.
  • Gary G.
  , 2000. No abstract provided
• Plasticity of zirconium at intermediate temperatures: effect of a small quantity of sulfur
  
  • Ferrer F.
  • Bretheau Th.
  • Crépin Jérôme
  • Barbu A.
  , 2000. No abstract provided
• Intelligent modelling of woven materials
  
  • Zarka Joseph
  • Doux Thierry
  , 2000.
• Optimal design of a beam with a direct link to CAD
  
  • Zarka J.
  • Hablot J. M.
  , 2000. No abstract provided
• Quelques exemples de vibrations et d'instabilité induites par le frottement
  
  • Nguyen Q. S.
  , 2000. No abstract provided