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Communication dans un congrès

Matériaux composites alumine/aluminium à gradient de fonction : modélisation numérique pour le calcul de la conductivité thermique effective

Nabil Ferguen, Emmanuel Bellenger, Mohamed Guessasma, Claudia Cogné, Christine Pelegris, Christian Courtois, Olivier Rigo

Ce travail propose de développer de nouveaux matériaux fonctionnels dans le domaine du transfert de chaleur. Ces matériaux à gestion de flux de chaleur doivent être capables de conduire à un management thermique. Un modèle numérique est développé permettant de simuler le procédé expérimental d…

CFM 2011 - 20ème Congrès Français de Mécanique, Aug 2011, Besançon, France. ⟨hal-03422866⟩

Article dans une revue

Stochastic perturbation of sweeping process and a convergence result for an associated numerical scheme

Frederic Bernicot, Juliette Venel

Here we present well-posedness results for first order stochastic differential inclusions, more precisely for sweeping process with a stochastic perturbation. These results are provided in combining both deterministic sweeping process theory and methods concerning the reflection of a Brownian…

Journal of Differential Equations, 2011, 251 (4-5), pp.1195-1224. ⟨10.1016/j.jde.2011.03.010⟩. ⟨hal-00448064⟩

Article dans une revue

Singular behavior of the solution of the Cauchy-Dirichlet heat equation in weighted L^p -Sobolev spaces

Colette De Coster, Serge Nicaise

We consider the heat equation on a polygonal domain Ω of the plane in weighted L^p-Sobolev spaces ∂_t u − ∆u = h, in Ω × ]0, T [, u = 0, on ∂Ω × [0, T ], u(•, 0) = 0, in Ω. Here h belongs to L^p (0, T ; L^p_µ (Ω)), where L^p_µ (Ω) = {v ∈ L^p_loc (Ω) : r^µ v ∈ L^p (Ω)}, with a real parameter µ and r…

Bulletin of the Belgian Mathematical Society - Simon Stevin, 2011, 18, pp.769-780. ⟨hal-03721680⟩

Article dans une revue

An extended finite element method for 2D edge elements

Stephanie Lohrengel, François Lefèvre, Serge Nicaise

A new extended Finite Element Method based on two-dimensional edge elements is presented and applied to solve the time-harmonic Maxwell equations in domains with cracks. Error analysis is performed and shows the method to be convergent with an order of at least O(h1/2-η). The implementation of the…

International Journal of Numerical Analysis and Modeling, 2011, 8 (4), pp.641-645. ⟨hal-01888373⟩

Article dans une revue

Optimal convergence analysis for the extended finite element method

Serge Nicaise, Yves Renard, Elie Chahine

We establish some optimal a priori error estimate on some variants of the eXtended Finite Element Method (Xfem), namely the Xfem with a cut-off function and the standard Xfem with a fixed enrichment area. The results are established for the Lame system (homogeneous isotropic elasticity) and the…

International Journal for Numerical Methods in Engineering, 2011, 86, pp.528-548. ⟨10.1002/nme.3092⟩. ⟨hal-00339853v2⟩

Thèse

Étude des phénomènes de transport dans un réacteur catalytique pilote de type filaire, Study of the external transport phenomena in a catalytic pilot single pellet string reactor

Ana Isabel Fernandes Hipolito

L’extrapolation des réacteurs catalytiques nécessite l’acquisition des données cinétiques sur des réacteurs à petite échelle dans les conditions opératoires industrielles. Le critère de dimensionnement utilisé lors de la réduction d’échelle est la conservation de la vitesse volumique horaire, ce…, Small size fixed-bed reactors are a common choice for testing industrial supported catalyst under industrial operating conditions. The most common criterion for reactor’s scale-down is based on the conservation of the liquid hourly space velocity which leads to a very low fluid flow velocity at the…

Alimentation et Nutrition. Université Claude Bernard - Lyon I, 2010. Français. ⟨NNT : 2010LYO10285⟩. ⟨tel-00733810⟩

Thèse

Synthèses par voies solide et hydrothermale pour céramiques de type BNT - BT - BKT, Solid state and hydrothermal syntheses for BNT - BT - BKT based ceramics

Jean-François Trelcat

Ce travail a pour objet l’étude de l’un des systèmes les plus prometteurs en tant que substitut au PZT, le ternaire Bi0,5Na0,5TiO3 - BaTiO3 - Bi0,5K0,5TiO3. La première partie de la thèse s’est focalisée sur la synthèse par voie solide de ce système et a permis une estimation plus affinée de la…, This study focuses on the study of one of the most promising systems as an alternative to PZT, the Bi0,5Na0,5TiO3 - BaTiO3 - Bi0,5K0,5TiO3 ternary system. The first part of the thesis consists on the solid state synthesis of this system and has allowed a more accurate estimation of the morphotropic…

Sciences de l'ingénieur [physics]. Université de Valenciennes et du Hainaut-Cambrésis, 2010. Français. ⟨NNT : 2010VALE0029⟩. ⟨tel-03009476⟩

Pré-publication, Document de travail

A posteriori error estimates for a finite element approximation of transmission problems with sign changing coefficients

Serge Nicaise, Juliette Venel

We perform the a posteriori error analysis of residual type of a transmission problem with sign changing coefficients. According to [6] if the contrast is large enough, the continuous problem can be transformed into a coercive one. We further show that a similar property holds for the discrete…

2010. ⟨hal-00517989⟩

Article dans une revue

Nonlinearity and scaling behavior in a soft lead zirconate titanate piezoceramic

Abdelowahed Hajjaji, Daniel Guyomar, Samira Touhtouh, Sebastien Pruvost, Yahia Boughaleb, Mohamed Rguiti, Christian Courtois, Anne Leriche, Khalil Benkhouja

Lead oxide-based ferroelectrics, represented by lead zirconate titanate [Pb(Zr,Ti)O3] or PZT), are the most widely used materials for piezoelectric actuators, sensors, and transducers due to their excellent piezoelectric properties. Most of these piezoelectric materials are employed under a variety…

Journal of Applied Physics, 2010, 108 (6), ⟨10.1063/1.3486510⟩. ⟨hal-04283059⟩

Article dans une revue

A posteriori error estimator based on gradient recovery by averaging for discontinuous Galerkin methods

Emmanuel Creusé, Serge Nicaise

We consider some (anisotropic and piecewise constant) diffusion problems in domains of R^2, approximated by a discontinuous Galerkin method with polynomials of any fixed degree. We propose an a posteriori error estimator based on gradient recovery by averaging. It is shown that this estimator gives…

Journal of Computational and Applied Mathematics, 2010, 234 (10), pp.2903-2915. ⟨10.1016/j.cam.2010.03.027⟩. ⟨hal-00768641⟩