Publications

2001

• Approches par les potentiels
  
  • Bornert Michel
  • Suquet P.
  , 2001, pp.45-90.
• Plasticité: approches en champ moyen
  
  • Zaoui A.
  , 2001, pp.17-44.
• Approche expérimentale de l'homogénisation
  
  • Bretheau T.
  , 2001, pp.147-169.
• Changement d'échelle: motivation et méthodologie
  
  • Zaoui A.
  , 2001, pp.19-39.
• On a predictive macroscopic contact-sliding wear model based on micromechanical considerations
  
  • Dragon-Louiset Marta
  International Journal of Solids and Structures, Elsevier, 2001, 38, pp.1625-1639. A model for the mild wear of two contacting solids and an analytical example are proposed in this article. The model includes the presence of an interface made of damaged materials, fluid and wear debris. It consists in a wear criterion, an interface law and complementary relations deduced from the mass conservation. A thermodynamical analysis provides energy-release rates associated with the evolution of the surfaces in contact and the mass fluxes due to wear. They are used as characteristic quantities in the formulation of the wear criterion and wear velocities. Given that the physics of the interface modify the global contact conditions, micromechanical considerations are developed and result in an interface law, modeling its evolution with an internal parameter: the volume fraction of wear debris. The relation between this parameter and wear velocities is obtained with the mass conservation equation, which completes the model and allows to apply it in a numerical simulation. As an example, a problem of a rigid punch sliding on an elastic worn-out half-plane is treated by means of integral equations, accounting on the presence of an interface according to the previous modeling. Stresses and strains are obtained analytically, as asymptotic expansion fields. (10.1016/S0020-7683(00)00065-2)
  DOI : 10.1016/S0020-7683(00)00065-2
• Grain-size-sensitive flow and shear-stress enhancement at the brittle-ductile transition of the continental crust
  
  • Gueydan Frédéric
  • Leroy Yves
  • Jolivet Laurent
  International Journal of Earth Sciences, Springer Verlag, 2001, 90 (1), pp.181-196. Localized shear zones along low-angle normal faults have been identified in regions of extension at the brittle–ductile transition of the continental crust. The possibility of the strain localizing at a depth of 10 km is interpreted here as a consequence of an increase in the equivalent shear stress applied to the flow of the lower crust. This enhancement of the flow stress is seen as a prerequisite for the triggering of brittle deformation mechanisms leading to strain localization. The lower crust rheology used to examine this stress increase is strain-rate, temperature and grain-size dependent, due to the coupling of dislocation and diffusion creep. The model structure proposed consists of a top layer, the upper crust, gliding rigidly above a bottom layer, the lower crust, which deforms in simple shear. During a short time interval (1400 years), the equivalent shear stress is found to increase by a factor of up to 3 (67 MPa for anorthite and 17 MPa for quartz). For anorthite, this stress could explain the activation of a Mohr-Coulomb failure with a friction coefficient of 0.2, which is reasonable at the depth of 10 km. Dislocation creep is activated during a rapid change in the prescribed velocity, whereas diffusion creep dominates if the velocity is held constant, highlighting the importance of grain-size sensitivity for lower crustal rheology. (10.1007/s005310000160)
  DOI : 10.1007/s005310000160
• Compared numerical techniques for FEM-BEM coupling
  
  • Mouhoubi Saida
  • Ulmet Laurent
  • Bonnet Marc
  , 2001, pp.249-258.
• Back analysis of loading parameters in shallow tunnels
  
  • Deng Desheng
  • Minh Duc Nguyen
  • Constantinescu Andrei
  , 2001 (1), pp.177-183. Convergence Confinement (CV-CF) Method is currently used in geo-engineering practice as a plane strain approximate tunnel calculation, for example, in the scope of a NATM construction procedure. However, although improvements have been recently achieved for some simple cases, this method is impeded by undetermination of the deconfining ratio value λo at the moment when support is laid. A back analysis method has been proposed on the basis of the Virtual Work Principle, in which the original CV-CF model is compared through an iterative process to a modified model in which the field measurements are prescribed. The parameter λo and the lateral stress ratio k0 of soil mass are back analysed. This method is very robust and works also for non linear rock mass behavior. For illustration of this back analysis method, 2D shallow tunnel calculation data are used as experimental data. (10.1201/9781003078562-21)
  DOI : 10.1201/9781003078562-21
• Experimental and numerical analysis of localization during sequential test for an IF-Ti steel
  
  • Hoc Thierry
  • Rey Collette
  • Raphanel Jean
  Acta Materialia, Elsevier, 2001, 49, pp.1835-1846. Localization of plastic deformation in polycrystals often occurs after a change of loading path. An experimental study using several techniques at different scales (scanning electron microscopy, microgrids, local orientation measurements, transmission electron microscopy) has been conducted on mild steel sheets (interstitial free titanium steel) prestrained by plane tension and then deformed by uniaxial tension along the first tensile axis or the transverse axis. In this way localization has been linked to microstructural anisotropy developed during the first loading path. A model based on crystalline plasticity has then been introduced in a finite element code (Abaqus) with a description of intragranular hardening linked to the evolution of the dislocation densities on each slip system. The simulations make use of a finite element representative pattern based on actual grain distribution in the aggregate. The computations predict a localization in good agreement with the experimental data and show a link between saturation of dislocation densities and concentration of plastic deformation. (10.1016/S1359-6454(01)00076-3)
  DOI : 10.1016/S1359-6454(01)00076-3
• Modelling an abrasive wear experiment by the boundary element method
  
  • Serre I.
  • Bonnet Marc
  • Pradeilles-Duval R. M.
  Comptes Rendus de l'Academie des Sciences Serie II, Gauthier-Villars, 2001, 329, pp.803-808. This Note presents a computational technique for simulating friction-induced wear in a tribology experiment on a plan/plan, ring-on-disc contact configuration. The boundary element method results in modest computing times and facilitates the mesh modifications used for tracking the wear profile evolution. A typical wear simulation result is presented and discussed. (10.1016/S1620-7742(01)01402-7)
  DOI : 10.1016/S1620-7742(01)01402-7
• Materially nonlinear analyses
  
  • Bonnet Marc
  , 2001.
• In-situ salt permeability testing
  
  • Brouard B.
  • Bérest P.
  • Durup G.
  , 2001, pp.139-157. No abstract provided
• Simulation de l'usure sous frottement : utilisation des éléments de frontière
  
  • Serre I.
  • Bonnet Marc
  • Pradeilles-Duval R. M.
  , 2001, pp.245-252. No abstract provided
• Unified approach for low and high cycle fatigue
  
  • Constantinescu Andrei
  • Dang Van Ky
  • Maitournam Habibou
  , 2001.
• Homogénéisation en mécanique des matériaux, Tome 2 : Comportements non linéaires et problèmes ouverts
  
  • Bornert Michel
  • Bretheau T.
  • Gilormini P.
  , 2001, pp.250 pages.
• Fatigue Analysis of Structures during Random Loadings
  
  • Zarka J.
  • Karaouni H.
  , 2001. No abstract provided
• A thermodynamic analysis of wear
  
  • Bui Huy Duong
  • Dragon-Louiset Marta
  • Stolz Claude
  , 2001, 2, pp.768-776. Wear phenomena due to contact and relative motion between two solids depend on the loading conditions and material mechanical behaviours and are charaterized by a loss of materials. Particles are detached from sound solids when some criteria are satisfied at the boundaries of the solids along the contact area. The evolution of the damaged surface is investigated in a thermomechanical analysis. This framework proposes a definition of mechanical local quantities, which can be usefull for the characterisation of wear process. Interface behaviour is analyzed. (10.1016/B978-012443341-0/50077-6)
  DOI : 10.1016/B978-012443341-0/50077-6
• Etude du comportement asymptotique de structures élastoviscoplastiques sous chargement cyclique : utilisation du contrôle optimal
  
  • Peigney Michaël
  • Stolz C.
  , 2001, pp.327-334. No abstract provided
• Moving discontinuities : applications to fracture and wear
  
  • Stolz C.
  , 2001.
• Modèles simplifiés par programmation génétique : prise en compte du sens physique
  
  • Ratle A.
  • Sebag Michèle
  , 2001, pp.821-828. No abstract provided
• On the identification of elastoviscoplastic constitutive laws from indentation tests
  
  • Constantinescu Andreï
  • Tardieu Nicolas
  Inverse Problems in Engineering, Informa UK (Taylor & Francis), 2001, 9 (1), pp.19-44. This paper addresses the identification of the parameters of a nonlinear constitutive law from indentation tests. The identification problem is considered as a constrained minimization problem and the gradient is computed using the adjoint state method, in spite of the difficulties of the underlying contact problem. This provides a general framework to perform optimization in some problems involving contact conditions and nonlinear material behaviour. The case of a Maxwell viscoelastic and a Norton-Hoff elastoviscoplastic constitutive law are treated extensively and a series of numerical identification examples are shown. (10.1080/174159701088027751)
  DOI : 10.1080/174159701088027751
• Assessment of Welded Structures by a Local Multiaxial Fatigue Approach
  
  • Dang Van Ky
  • Bignonnet André
  • Fayard Jean-Luc
  • Janosch Jean-Jacques
  Fatigue and Fracture of Engineering Materials and Structures, Wiley-Blackwell, 2001, 24 (5), pp.369-376. A new local multiaxial computing method for the fatigue assessment of welded structures is presented. This approach is based on the use of an equivalent stress derived from the multiaxial fatigue criterion proposed by Dang Van for plain machined specimens. Application to fillet welds allows a better description of the influence of local geometries and residual stress states. These factors are related to the weld process and the quality of the weld. This approach, associated with definite shell finite element meshing rules in order to take account of the increase of local rigidity introduced by the weld, is also successfully used to assess the fatigue resistance of welded automotive structures. (10.1046/j.1460-2695.2001.00399.x)
  DOI : 10.1046/j.1460-2695.2001.00399.x
• Détermination de cycle limite par une méthode cyclique directe
  
  • Pommier Benjamin
  • Maitournam Habibou
  • Gaombalet Jérôme
  , 2001, pp.335-342.