Publications

2003

• Génie parasismique : aspects dynamiques et vibratoires en génie civil
  
  • Luong Minh-Phong
  , 2003, pp.3 tomes. Actes du colloque AFPS 2003. Plus de 160 communications ont été présentées, réparties selon les thèmes suivants : - Géosciences (vol. 1) : sismologie générale et aléa déterministe ; mouvements sismiques pour l'ingénieur ; effets de site classiques ; interaction sol-structure et effet de site "urbains" ; géotechnique parasismique (sols, fondations et ouvrages). - Dynamique des structures et conception (vol. 2) : méthodes d'analyse et de modélisation (analyse simplifiée et indicateurs de nocivité, méthodes spécifiques) ; expérimentation ; constructions métalliques ; équipements industriels et structures particulières ; ponts. - Gestion de l'existant et du risque (vol. 3) : diagnostic et renforcement de l'existant ; existant nucléaire ; méthode d'estimation de la vulnérabilité à grande échelle ; scénarios et vulnérabilité urbaine ; aspects socio-économiques ; vers un nouveau zonage sismique de la France. - Benchmark Camus (vol. 3).
• 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
• Identification de failles sismiques par une fonctionnelle de réciprocité généralisée
  
  • Bui Huy Duong
  • Constantinescu Andrei
  • Maigre Hubert
  , 2003, 1, pp.13-20.
• Microstructure influence on the damage initiation in unirradiated zirconium alloys
  
  • Elbachiri K.
  • Crépin Jérôme
  • Rebeyrolle V.
  • Bretheau T.
  , 2003. No abstract provided
• Identification de lois de comportement cristallines à partir du couplage EBSD/microextensometrie/Eléments Finis. Application au zirconium grade 702
  
  • Dexet M.
  • Crépin Jérôme
  • Gélébart L.
  , 2003. No abstract provided
• 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
• 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
• 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.
• 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
• An example of stick-slip and stick-slip-separation waves
  
  • Moirot Franck
  • Son Nguyen Quoc
  • Oueslati Abdelbacet
  European Journal of Mechanics - A/Solids, Elsevier, 2003, 22, pp.107-118. The dynamical problem of a brake-like mechanical system composed of an elastic cylindrical tube with Coulomb's friction in contact with a rigid and rotating cylinder is considered. This model problem enables us to give an example of non-trivial periodic solutions in the form of stick-slip or stick-slip-separation waves propagating on the contact surface. A semi-analytical analysis of stick-slip waves is obtained when the system of governing equations is reduced by condensation to a simpler system involving only the contact displacements. This reduced system, of only one space variable in addition to time, can be solved almost analytically and gives some interesting informations on the existence and the characteristics of stick-slip waves such as the wave numbers on the circumference, stick and slip proportions, wave celerities, tangential and normal forces. It is shown in particular that the stick-slip-separation solutions would occur for small normal pressures or high rotational speeds. Since the analytical discussion becomes cumbersome in this case, a second approach based on numerical analysis by the finite element method is performed. The existence and the characteristics of stick-slip and stick-slip-separation waves are discussed numerically.
• 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
• 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
• 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
• Planar crack identification for the transient heat equation
  
  • Ben Abda A.
  • Bui Huy Duong
  Journal of Inverse and Ill-posed Problems, De Gruyter, 2003, 11, pp.27-31. We consider the inverse problem of crack determination related to the non-destructive thermal testing of materials process. Using arbitrary transient heat flux applied to the external boundary and measuring the induced planar cracks. (10.1515/156939403322004919)
  DOI : 10.1515/156939403322004919
• Optimal dip based on dissipation of backthrusts and hinges in fold-and-thrust belts
  
  • Maillot Bertrand
  • Leroy Yves
  Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2003, 108 (B6), pp.2320. Back thrusts and hinges are two types of transition between rigid sections of hanging walls observed in fold‐and‐thrust belts. Back thrusts are typical of frictional and homogeneous solids and hinges of creeping and layered materials. Our objective is to study the orientation of these transitions for the special case of a lower flat‐ramp transition in a fault‐bend fold with the following general two‐step methodology. In the first step, the forces acting on the transition are determined using equilibrium of each rigid section. In the second step, the optimal dip of the transition is obtained by minimizing the total dissipation of the structure. The three sources of dissipation, of comparable magnitude, are at the transition, on the flat, and on the ramp. For frictional material flows, the back thrusts are velocity discontinuities with optimal dips always less than half the complementary ramp angle, leading to hanging wall thickening. The optimal dip agrees well with the results of physical analogue and numerical experiments. For creeping and layered materials, it is shown that a destabilizing deformation mechanism, selected to be flexural slip, is necessary for the strain to localize and the existence of hinges to be justified. Activation of flexural slip reduces dissipation at the transition and affects the optimal transition dip. The two‐step methodology proposed here could be seen as a first attempt in producing mechanically balanced cross sections accounting for material rheology. This approach should complement the now classical kinematic models of folding. (10.1029/2002JB002199)
  DOI : 10.1029/2002JB002199
• Etude expérimentale des micro-mécanismes d'endommagement et de rupture des zircaloys hydrurés
  
  • Racine A.
  • Bornert Michel
  • Sainte-Catherine C.
  • Caldemaison D.
  Journal de Physique IV Proceedings, EDP Sciences, 2003, 106, pp.109-118. Afin de mieux comprendre les mécanismes d'endommagement et de rupture des Zircaloy, des essais de traction sur anneaux ont été réalisés in-situ sous MEB sur des éprouvettes de tube de gainage de combustible, contenant environ 150 ppm d'hydrogène et avec différentes orientations d'hydrures : de circonférentielle à radiale. Ces essais ont mis en évidence deux modes de rupture selon l'orientation des hydrures. Les éprouvettes avec hydrures radiaux (perpendiculaires à la sollicitation) rompent brutalement par propagation d'une fissure suivant un chemin d'hydrures radiaux alignés. Les niveaux de déformation au voisinage de la fissure, estimés par des techniques de micro-électrolithographie associées à celle d'analyse par corrélation d'images, sont très faibles, de l'ordre du %. En revanche, dans celles avec hydrures circonférentiels (suivant l'axe de sollicitation), les effets de structure prédominent : des bandes de cisaillement macroscopique apparaissent, dans lesquelles la déformation se localise. En dehors de ces zones de localisation intense, la déformation reste inférieure à 10% et très peu d'endommagement par germination de cavités ou fissuration d'hydrures a été observé. Les hétérogénéités du champ local de déformation, corrélées à la présence des hydrures, semblent établir l'influence de ceux-ci sur le mode de déformation local, mais ces observations nécessitent d'être confirmées. (10.1051/jp4:20030221)
  DOI : 10.1051/jp4:20030221
• Exploiting partial or complete geometrical symmetry in 3D symmetric Galerkin indirect BEM formulations
  
  • Bonnet Marc
  International Journal for Numerical Methods in Engineering, Wiley, 2003, 57, pp.1053-1083. Procedures based on group representation theory, allowing the exploitation of geometrical symmetry in symmetric Galerkin BEM formulations, are investigated. In particular, this investigation is based on the weaker assumption of partial geometrical symmetry, where the boundary has two disconnected components, one of which is symmetric; e.g. this can be very useful for defect identification problems. The main development is expounded in the context of 3D Neumann elastostatic problems, considered as model problems; and then extended to SGBIE formulations for Dirichlet and/or scalar problems. Both Abelian and non-Abelian finite symmetry groups are considered. The effectiveness of the present approach is demonstrated through numerical examples, where both partial and complete symmetry are considered, in connection with both Abelian and non-Abelian symmetry groups. (10.1002/nme.716)
  DOI : 10.1002/nme.716
• A procedure for identifying the plastic behaviour of single crystals from the local response of polycrystals
  
  • Hoc Thierry
  • Crépin Jérôme
  • Gélébart Lionel
  • Zaoui André
  Acta Materialia, Elsevier, 2003, 51, pp.5479-5490. The overall and local tensile responses of an α iron multicrystalline sample are investigated in order to derive the plastic constitutive equations for the constituent single crystals. The macroscopic stress–strain curve and some statistical characteristics of the strain field measured on the sample surface are compared with their simulated counterparts. The optimal values of the material parameters of four types of hardening laws are derived by a minimization procedure. The best results are obtained with a nonlinear anisotropic law which uses the dislocation densities on the slip systems. This procedure is then validated on a fine-grained polycrystalline sample of a similar material by using the measured displacement field on the edge of a selected area as boundary conditions for finite element method (FEM) computation. The resulting optimal material parameters for the single crystal are found to be consistent with the values available in the literature, and the whole simulated strain fields as well as the evolution of the crystallographic texture, is compared satisfactorily with the experimental data. (10.1016/S1359-6454(03)00413-0)
  DOI : 10.1016/S1359-6454(03)00413-0
• Materially Nonlinear Analysis
  
  • Bonnet Marc
  , 2003, pp.55-114. This chapter presents a review of domain-boundary element techniques for solving materially nonlinear solid mechanics problems. Quasi-static and dynamic formulations are addressed, with emphasis on the use of implicit constitutive integration techniques and the local and global consistent tangent operators. Symmetric Galerkin BEM formulations are also presented. A section is devoted to steady-state elastoplastic calculations for moving loads, and another to the simulation of abrasive wear, both types of nonlinear analyses being well-suited to D/BEM treatments. Another section deals with energy methods in fracture mechanics. Finally, a symmetric formulation for BEM-FEM coupling is presented as another way to use BEM, this time combined with FEM, for materially nonlinear analyses. (10.1007/978-3-7091-2790-2_2)
  DOI : 10.1007/978-3-7091-2790-2_2