Publications

2003

• Contribution du fluage à froid et de l'hydrogène à la fissuration anormale du Ti 6246 sous chargement cyclique à fort Kmax
  
  • Doquet V.
  • Mignot F.
  • Sarrazin-Baudoux C.
  , 2003. No abstract provided
• Couplage EBSD - micro-extensométrie et identification de lois cristallines
  
  • Roos A.
  • Hoc T.
  • Gélébart L.
  • Crépin Jérôme
  • Bornert Michel
  • Bretheau T.
  , 2003. No abstract provided
• Caractérisation de la répartition de la déformation dans les matériaux hétérogènes
  
  • Doumalin Pascal
  • Bornert Michel
  • Crépin Jérôme
  Mechanics & Industry, EDP Sciences, 2003, 4, pp.607-617. On présente une méthode originale de caractérisation de la répartition de la déformation dans les matériaux hétérogènes, basée sur l'adaptation des techniques statistiques de caractérisation morphologique par covariance à 2 points aux champs locaux de déformation mesurés par microextensométrie MEB. Elle permet de montrer que le comportement mécanique n'est pas uniquement la conséquence d'interactions très locales entre grains ou domaines de phases voisins, mais résulte aussi de phénomènes à plus grande portée. (10.1016/j.mecind.2003.09.002)
  DOI : 10.1016/j.mecind.2003.09.002
• Thermomechanical properties of polycarbonate under dynamic loading
  
  • Lerch V.
  • Gary G.
  • Hervé P.
  Journal de Physique IV Proceedings, EDP Sciences, 2003, 110, pp.159-164. In the present study, dynamic compression tests have been performed on polycarbonate (PC) specimen for strain rates in the range of 500 to 2000s -1 and on aluminum for a strain rate around 1300s -1 using a Split Hopkinson Pressure Bar (SHPB). Temperature measurement has been carried out using a fast response infrared optical pyrometer which is able to measure the surface temperature rise of a specimen during the tests. The temperature data shows that the mechanical work is not completely converted into heat. It implies the existence of a stored energy within the material and possibly a subsequent delay for the conversion of mechanical work into heat. (10.1051/jp4:20020687)
  DOI : 10.1051/jp4:20020687
• Linear stability analysis in fluid-structure interaction with transpiration. Part II: Numerical analysis and applications
  
  • Fernández Miguel Angel
  • Le Tallec Patrick
  Computer Methods in Applied Mechanics and Engineering, Elsevier, 2003, 192 (43), pp.4837-4873. This paper constitutes the numerical counterpart of the mathematical framework introduced in Part I. We address the problem of flutter analysis of a coupled fluid-structure system involving an incompressible Newtonian fluid and a reduced structure. We use the Linearization Principle approach developed in Part I, particularly suited for fluid-structure problems involving moving boundaries. Thus, the stability analysis is reduced to the computation of the leftmost eigenvalues of a coupled eigenproblem of minimal complexity. This eigenproblem involves the linearized incompressible Navier-Stokes equations and those of a reduced linear structure. The coupling is realized through specific transpiration interface conditions. The eigenproblem is discretized using a finite element approximation and its smallest real part eigenvalues are computed by combining a generalized Cayley transform and an implicit restarted Arnoldi method. Finally, we report three numerical experiments : a structure immersed in a fluid at rest, a cantilever pipe conveying a fluid flow and a rectangular bridge deck profile under wind effects. The numerical results are compared to former approaches and experimental data. The quality of these numerical results is very satisfactory and promising. (10.1016/j.cma.2003.08.001)
  DOI : 10.1016/j.cma.2003.08.001
• Statistical and Numerical analysis of the nonlinear behaviour of a porous materials with a heterogeneous distribution of pores
  
  • Bilger Nicolas
  • Bornert Michel
  • Auslender François
  • Michel Jean-Claude
  • Moulinec Hervé
  • Suquet Pierre
  • Zaoui André
  , 2003. The yield stress of a ductile 2D porous material with a heterogeneous distribution of pores is investigated by means of a numerical tool based on the Fast Fourier Transform. Random distributions of circular voids, with a uniform or variable pore size and with overlapping or clearly separated pores, are compared, for a same overall porosity, to microstructures obtained as the intersection of the previous ones with a boolean scheme with a larger characteristic size. For pure shear and even more under purely hydrostatic load, the numerical simulations show that the pore distribution has a strong effect on the yield stress, with the so-called “Hashin Composite Cylinders Assemblage” being the hardest microstructure and the connected clusters the softest, while disconnected clusters lead to intermediate responses. An image analysis tool for the statistical characterization of the pore distribution is then proposed. It is based on the distribution function of the distance function, the width of which increases with the presence of clusters. An additional analysis allows one to distinguish microstructures with connected clusters from those with disconnected ones.
• Testing with SHPB from quasi-static to dynamic strain rates
  
  • Ohtman R.
  • Bussac M. N.
  • Collet P.
  • Gary G.
  Journal de Physique IV Proceedings, EDP Sciences, 2003, 110, pp.397-404. We have developed a new method for separating dispersive waves in elastic and viscoelastic rods from three-point strain and one-point velocity measurements. Stress, strain, displacement and velocity, which were supposed to be homogenous in a rod section, were therefore determined at any point ofthe bar. This method is based on the assumption of a one dimensional and single mode dispersive wave propagation. This method was used in the frequency domain and took into account wave dispersion. It was shown to be stable with respect to noise. 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 more limited by the length of the bars. The method was used to evaluate the rate sensitivity ofaluminum honeycomb over a wide range ofstrain-rates (from 10 -2 to 1000 s -1). (10.1051/jp4:20020726)
  DOI : 10.1051/jp4:20020726
• Ondes adhérence-glissement-décollement sous contact unilatéral frottant
  
  • Oueslati Abdelbacet
  • Nguyen Quoc Son
  • Baillet Laurent
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2003, 331 (2), pp.133-140. Il s'agit d'une étude numérique sur la réponse dynamique d'un système de deux cylindres coaxiaux, en rotation relative avec contact unilatéral frottant suivant la loi de Coulomb. On complète les résultats semi-analytiques antérieurs obtenus dans Moirot, Nguyen, C. R. Acad. Sci. Paris Sér. IIb 328 (2000) 663–669, sur les ondes adhérence–glissement en simulant par le calcul numérique la transition dynamique du système à partir d'un état initial quelconque vers la propagation d'une onde de surface. Le cas des ondes adhérence–glissement–décollement est examiné. (10.1016/S1631-0721(02)00009-8)
  DOI : 10.1016/S1631-0721(02)00009-8
• Creep of polycrystalline anorthite and diopside
  
  • Dimanov Alexandre
  • Lavie Marie-Pierre
  • Ingrin Jannick
  • Dresen Georg
  • Jaoul Olivier
  Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2003, 108 (B1), pp.doi:10.10292002JB001815. (10.1029/2002JB001815)
  DOI : 10.1029/2002JB001815
• Peierls-Nabarro landscape for martensitic phase transitions
  
  • Truskinowsky Lev
  • Vainchtein Anna
  Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2003, 67 (17). We consider a prototypical model of a martensitic phase transition, which takes discreteness and nonlocality into account and allows one to reconstruct explicitly the Peierls-Nabarro energy landscape for the phase boundaries. We solve the discrete problem exactly and obtain a simple expression for the critical Peierls force that is necessary to release a lattice-trapped phase boundary. The model suggests specific relations between the microscopic parameters of the lattice and the size of the hysteresis in martensitic materials, which we verify for the cubic-$β'_1$-monoclinic phase transition in Cu-Al-Ni alloy. (10.1103/physrevb.67.172103)
  DOI : 10.1103/physrevb.67.172103
• The treatment of 'pinching locking' in 3D-shell elements
  
  • Chapelle Dominique
  • Ferent Anca
  • Le Tallec Patrick
  ESAIM: Mathematical Modelling and Numerical Analysis, Société de Mathématiques Appliquées et Industrielles (SMAI) / EDP, 2003, 37 (1), pp.143-158. We consider a family of shell finite elements with quadratic displacements across the thickness. These elements are very attractive, but compared to standard general shell elements they face another source of numerical locking in addition to shear and membrane locking. This additional locking phenomenon - that we call ''pinching locking'' - is the subject of this paper and we analyse a numerical strategy designed to overcome this difficulty. Using a model problem in which only this specific source of locking is present, we are able to obtain error estimates independent of the thickness parameter, which shows that pinching locking is effectively treated. This is also confirmed by some numerical experiments of which we give an account. (10.1051/m2an:2003015)
  DOI : 10.1051/m2an:2003015
• Etude micromécanique de la disparition du seuil de fissuration par fatigue dans un alliage de titane biphasé à fort K_max
  
  • Mignot Frédéric
  • Doquet Véronique
  • Sarrazin-Baudoux Christine
  • Petit Jean
  Journal de Physique IV Proceedings, EDP Sciences, 2003, 106, pp.33-42. L'alliage Ti6246 présente, lors d'essais de fissuration par fatigue à K_max constant et ΔK décroissant un comportement atypique : lorsque K_max> 0.7K_IC, on observe, sous air comme sous vide, au lieu du seuil attendu, un régime de propagation à vitesse constante, dix fois plus élevée à l'ambiante qu'à 500°C. Le fluage, qui se manifeste dès l'ambiante dans cet alliage semble jouer un rôle dans ce phénomène. Toutefois, des analyses par spectrométrie de masse d'ions secondaires font apparaître une sur-concentration en hydrogène au voisinage d'une fissure développée dans le régime anormal. Des essais de fissuration, traction et fluage sont donc entrepris sur le matériau brut, appauvri ou enrichi en hydrogène, pour partie dans la chambre d'un microscope électronique à balayage, dans le but d'explorer ce phénomène. On constate qu'un enrichissement en hydrogène augmente la ductilité du matériau et sa tendance au fluage à l'ambiante et un enrichissement plus prononcé la diminue. (10.1051/jp4:20030213)
  DOI : 10.1051/jp4:20030213
• Crystallographic fatigue crack growth in a polycrystal: simulations based on FEM and discrete dislocation dynamics
  
  • Bertolino Graciela
  • Doquet Véronique
  • Sauzay Maxime
  , 2003. An attempt to model the variability of short cracks development in high-cycle fatigue is made by coupling finite element calculations of the stresses ahead of a microcrack in a polycrystal with simulations of crack growth along slip planes based on discrete dislocations dynamics. The model predicts a large scatter in growth rates related to the roughness of the crack path. It also describes the influence of the mean grain size and the fact that overloads may suppress the endurance limit by allowing arrested cracks to cross the grain boundaries.
• Remarques sur les contraintes résiduelles
  
  • Bérest Pierre
  • Vouille Gérard
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2003, 331 (6), pp.455-460. Les contraintes résiduelles observées dans les solides peuvent résulter de déformations initiales non compatibles. Elles sont alors déterminées, en général, par le tenseur d'incompatibilité du tenseur des déformations initiales. Toutefois, réciproquement, la nullité du tenseur d'incompatibilité ne suffit pas pour conclure à l'absence de contraintes résiduelles, dans le cas où le solide est non simplement connexe, ou présente des surfaces de discontinuité. Plusieurs exemples sont présentés. (10.1016/S1631-0721(03)00090-1)
  DOI : 10.1016/S1631-0721(03)00090-1
• Linear stability analysis in fluid-structure interaction with transpiration. Part I: Formulation and mathematical analysis
  
  • Fernández Miguel Angel
  • Le Tallec Patrick
  Computer Methods in Applied Mechanics and Engineering, Elsevier, 2003, 192 (43), pp.4805-4835,. The aim of this work is to provide a new Linearization Principle approach particularly suited for problems in fluid-structure stability. The complexity here, and the main difference with respect to the classical approach, comes from the fact that the full non-linear fluid equations are written in a moving (i.e. time dependent) domain. The underlying idea of our approach uses transpiration techniques [J. Fluid Mech. 4 (1958) 383 ; G. Mortchéléwicz, Application of linearized Euler equations to flutter, in : 85th AGARD SMP Meeting, Aalborg, Denmark, 1997 ; P. Raj, B. Harris, Using surface transpiration with an Euler method for cost-effective aerodynamic analysis, in : AIAA 24th Applied Aerodynamics Conference, number 93-3506, Monterey, Canada, 1993 ; AIAA 27(6) (1989) 777], with the formalization and linearization recently developed in [Rév. Européenne Élém. Finis, 9(6-7) (2000) 681, A. Dervieux (Ed.), Fluid-Structure Interaction, Kogan Page Science, London, 2003 (Chapter 3)]. This allows us to obtain a new grid independent coupled spectral problem involving the linearized Navier-Stokes equations and those of a reduced linear structure. The coupling is realized through specific transpiration conditions acting on a fixed interface, while keeping a fixed fluid domain. We provide a rigorous mathematical treatment of this eigenproblem. We prove that the corresponding eigenmodes, characterizing the free evolution of the system, can be obtained from the characteristic values of a compact operator acting on a Hilbert space. Moreover, we localize the eigenfrequencies of the system in a parabolic region of the complex plan centered along the positive real axis. (10.1016/j.cma.2003.07.001)
  DOI : 10.1016/j.cma.2003.07.001
• Prise en compte de la rugosité dans le prévision de la tenue en fatigue des roulements
  
  • Thoquenne Guillaume
  • Lubrecht Ton
  • Dang Van Ky
  • Maitournam Habibou
  • Peyrac Catherine
  • Lieurade Henri-Paul
  , 2003.
• A “Numerical Mesoscope” for the Investigation of Local Fields in Rate-Dependent Elastoplastic Materials at Finite Strain
  
  • Haddadi Halim
  • Teodosiu Cristian
  • Héraud S.
  • Allais L.
  • Zaoui André
  , 2001, 108, pp.311-320. We propose a “numerical mesoscope” which could be used for the analysis of the local mechanical fields over small critical areas of microheterogeneous materials, in order to predict the local initiation of specific deformation or damage mechanisms. The subdomain under investigation is embedded in a very large homogeneous matrix obeying the overall behavior of the studied material, as determined experimentally. This matrix is subjected to homogeneous stress or strain boundary conditions and the homogeneous elements of the subdomain and their interfaces are given their known or assumed constitutive behavior. A finite element analysis is then performed on the whole body by making use of different constitutive equations within the subdomain and in the surrounding matrix. The general methodology of this approach is reported and applied to a metallic rate-dependent elastoplastic polycrystal and to microheterogeneous subdomains consisting of given multicrystalline patterns whose grains obey crystalline elastoplastic constitutive equations of Schmid type at finite strain. Application to the intergranular creep damage of a stainless steel shows a good agreement between the largest computed normal stresses on the grain boundaries and the observed debonded boundaries of the actual material. (10.1007/978-94-017-0297-3_28)
  DOI : 10.1007/978-94-017-0297-3_28
• Modélisation de la fatigue des matériaux à mémoire de forme
  
  • Moumni Ziad
  • Maitournam Habibou
  • Dang Van Ky
  , 2003, 1, pp.413-419.
• Modeling the dynamics of piano keys
  
  • Brenon Céline
  • Boutillon Xavier
  , 2003. The models of piano keys available in the literature are crude: two degrees of freedom and a very few dynamical or geometrical parameters. Experiments on different piano mechanisms (upright, grand, one type of numerical keyboard) exhibit strong differences in the two successive phases of the key motion which are controlled by the finger. Understanding the controllability of the escapement velocity (typically a few percents for professional pianists), the differences between upright and grand pianos, the rationale for the numerous independent adjustments by technicians, and the feel by the pianist require sophisticated modeling. In addition to the inertia of the six independently moving parts of a grand piano mechanism, a careful modeling of friction at pivots and between the jack and the roll, of damping and nonlinearities in felts, and of internal springs will be presented. Simulations will be confronted to the measurements of the motions of the different parts. Currently, the first phase of the motion and the transition to the second phase are well understood while some progress must still be made in order to describe correctly this short but important phase before the escapement of the hammer. [Work done in part at the Laboratory for Musical Acoustics, Paris.] (10.1121/1.4777652)
  DOI : 10.1121/1.4777652
• Fissuration par fatigue d'un acier pour application ferroviaire: effet synérgétique des modes d'ouverture et de cisaillement sous chargement séquentiel
  
  • Doquet V.
  • Pommier S.
  , 2003. No abstract provided
• Analytical methods for dynamic response of underground structures
  
  • Kurose A.
  • Bérest P.
  • Brouard B.
  , 2003, pp.263-276 (tome 1). No abstract provided
• Identification numérique des fissures planes en élastodynamique
  
  • Bui Huy Duong
  • Constantinescu Andrei
  • Maigre Hubert
  , 2003, 1, pp.201-208.
• On the stress-wave imaging of cavities in a semi-infinite solid
  
  • Guzina B. B.
  • Nintcheu Fata S.
  • Bonnet Marc
  International Journal of Solids and Structures, Elsevier, 2003, 40, pp.1505-1523. The problem of mapping underground cavities from surface seismic measurements is investigated within the framework of a regularized boundary integral equation (BIE) method. With the ground modeled as a uniform elastic half-space, the inverse analysis of elastic waves scattered by a three-dimensional void is formulated as a task of minimizing the misfit between experimental observations and theoretical predictions for an assumed void geometry. For an accurate treatment of the gradient search technique employed to solve the inverse problem, sensitivities of the predictive BIE model with respect to cavity parameters are evaluated semi-analytically using an adjoint problem approach and a continuum kinematics description. Several key features of the formulation, including the rigorous treatment of the radiation condition for semi-infinite solids, modeling of an illuminating seismic wave field, and treatment of the prior information, are highlighted. A set of numerical examples with spherical and ellipsoidal cavity geometries is included to illustrate the performance of the method. It is shown that the featured adjoint problem approach reduces the computational requirements by an order of magnitude relative to conventional finite-difference estimates, thus rendering the three-dimensional elastic-wave imaging of solids tractable for engineering applications. (10.1016/S0020-7683(02)00650-9)
  DOI : 10.1016/S0020-7683(02)00650-9
• Numerical and experimental modal analysis of the reed and pipe of a clarinet
  
  • Facchinetti Matteo
  • Boutillon Xavier
  • Constantinescu Andrei
  Journal of the Acoustical Society of America, Acoustical Society of America, 2003, 113 (5), pp.2874-2883. A modal computation of a complete clarinet is presented by the association of finite-elementmodels of the reed and of part of the pipe with a lumped-element model of the rest of the pipe. In the first part, we compare modal computations of the reed and the air inside the mouthpiece and barrel with measurements performed by holographic interferometry. In the second part, the complete clarinet is modeled by adjoining a series of lumped elements for the remaining part of the pipe. The parameters of the lumped-resonator model are determined from acoustic impedance measurements. Computed eigenmodes of the whole system show that modal patterns of the reed differ significantly whether it is alone or coupled to air. Some modes exhibit mostly reed motion and a small contribution of the acoustic pressure inside the pipe. Resonance frequencies measured on a clarinet with the mouthpiece replaced by the cylinder of equal volume differ significantly from the computed eigenfrequencies of the clarinet taking the actual shape of the mouthpiece into account and from those including the (linear) dynamics of the reed. This suggests revisiting the customary quality index based on the alignment of the peaks of the input acoustical impedance curve. (10.1121/1.1560212)
  DOI : 10.1121/1.1560212
• Identification of rock mass properties in elasto-plasticity
  
  • Deng D.
  • Nguyen Minh D.
  Computers and Geotechnics, Elsevier, 2003, 30, pp.27-40. A simple and effective back analysis method has been proposed on the basis of a new criterion of identification, the minimization of error on the virtual work principle. This method works for both linear elastic and nonlinear elasto-plastic problems. The elasto-plastic rock mass properties for different criteria of plasticity can be well identified based on field measurements. (10.1016/S0266-352X(02)00033-2)
  DOI : 10.1016/S0266-352X(02)00033-2