Publications

2003

• Mechanical behaviour of polymer nanocomposites: a discrete simulation approach
  
  • Chabert E.
  • Gauthier R.
  • Dendievel R.
  • Chazeau Laurent
  • Cavaille J. Y.
  , 2003. No abstract provided
• Distribution inter et intra-granulaire des déformations élastiques dans un acier charge élastiquement: analyse par diffraction et homogénéisation
  
  • Castelnau O.
  • Letouze N.
  • Crépin Jérôme
  • Caldemaison D.
  • Ceretti M.
  • Brenner R.
  , 2003. No abstract provided
• Influence de la microstructure dans l'initiation de l'endommagement des alliages de zirconium non irradies
  
  • Elbachiri K.
  • Crépin Jérôme
  • Rebeyrolle V.
  • Bretheau T.
  , 2003. No abstract provided
• Ondes de surface sous contact unilatéral et frottement de Coulomb
  
  • Nguyen Q. S.
  • Oueslati A.
  , 2003, pp.353-360 (tome 2). No abstract provided
• Analyse fréquentielle de la fatigue des structures
  
  • Moumni Ziad
  • Maitournam Habibou
  • Dang Van Ky
  , 2003, pp.191-198.
• Identification of behavior by inverse method performed on local deformation, Dislocations plasticity and metal forming
  
  • Hoc T.
  • Crépin Jérôme
  • Zaoui A.
  , 2003, pp.433-435. No abstract provided
• Growth and cellular differentiation: a physical-biochemical conundrum? The example of the hand
  
  • Schwartz Laurent H
  • Maitournam Habibou
  • Stolz C.
  • Steayert J. M.
  • Ho Ba Tho Marie-Christine
  • Halphen Bernard
  Medical Hypotheses, Elsevier, 2003, 61, pp.45-51. Currently, the predominant hypothesis explains cellular differentiation as an essentially genetic intracellular process. The goal of this paper is to suggest that cell growth and differentiation may be, simply, the result of physical and chemical constraints. Bone growth occurs at the level of cartilage conjunction (growth plate) in a zone of lesser constrain. It appears that this growth also induces muscle, tendon, nerve and skin elongation. This cartilage growth by itself seems to explain the elongation of the hand. Growth stops at puberty likely because of feed-back from an increasing muscle load. The ossification (that is differentiation of cartilage into bone) appears to result from the shear stress induced. The study of bone age, obtained by X-ray picture of the hand, shows that ossification of epiphyses is very precise both in time and space. Computer modelization suggests that this ossification occurs where shear stress is greatest. The cartilage which does not ossify (joint, nose, larynx, ear, bronchus, etc.) is not exposed to high shear. Shear stress induces the secretion of extracellular matrix and a change of the biochemical environment of the cell. Precipitation of calcium phosphate, as in ossification, seems related to the alkalosis induced by shear stress. To speak in more general terms, loss of cellular differentiation, as occurs with cancer, can result from a change in the physical–chemical environments. (10.1016/S0306-9877(03)00102-6)
  DOI : 10.1016/S0306-9877(03)00102-6
• An estimate of maximum ground surface motion
  
  • Pecker Alain
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2003, 331, pp.661-666. The increasing need for probability seismic hazard assessment (PSHA) of critical facilities sometimes leads to unrealistic earthquake scenarios with very high induced ground motions. From a physical standpoint these high motions cannot exist because of the limiting resistance capacity of the soil strata through which the seismic waves travel. A simple analytical model is proposed to estimate a bound to the maximum ground surface acceleration that any soil deposit can transfer. (10.1016/j.crme.2003.08.001)
  DOI : 10.1016/j.crme.2003.08.001
• Nonhydrostatic stabilization of an orthorhombic phase of zirconia
  
  • Fadda Giuseppe
  • Truskinowsky Lev
  • Zanzotto Giovanni
  Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2003, 68 (13). An explicit polynomial strain-energy function for tetragonal-orthorhombic-monoclinic zirconia (ZrO2), calibrated from the conventional hydrostatic p−T phase diagram, is used to study the effects of nonhydrostatic loading on the phase equilibria in this material. Several representative sections of the phase diagram of ZrO2 in temperature and stress space, containing both triple and critical points, are computed. A new orthorhombic structure of ZrO2 is predicted to be the most stable phase for a variety of experimentally accessible shear loads, in a wide range of temperatures and pressures. (10.1103/PhysRevB.68.134106)
  DOI : 10.1103/PhysRevB.68.134106
• Explicit Kinetic Relation from “First Principles”
  
  • Truskinovsky L.
  • Vainchtein A.
  , 2003. We study a fully inertial discrete model of a martensitic phase transition which takes into account interactions of first and second nearest neighbors. Although the model is Hamiltonian at the microscale, it generates a nontrivial macroscopic relation between the velocity of the martensitic phase boundary and the conjugate configurational force. The apparent dissipation is due to the induced radiation of lattice waves carrying energy away from the front. (10.1007/0-387-26261-X_5)
  DOI : 10.1007/0-387-26261-X_5
• 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
• 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
• An `affine' micromechanical approach for the prediction of the elastoplastic behaviour of polycrystals at finite strain
  
  • Auslender F.
  • Bornert Michel
  • Hoc T.
  • Masson Renaud
  • Zaoui A.
  , 2003.
• La microextensométrie : un outil de la mécanique des matériaux
  
  • Bretheau T.
  • Crépin Jérôme
  • Doumalin P.
  • Bornert Michel
  Revue de Métallurgie, EDP Sciences, 2003, 5, pp.567-575. On présente ici une technique expérimentale, tant qualitative que quantitative, permettant de caractériser le champ de déformation dans un matériau hétérogène, sur un domaine représentatif de sa microstructure. Cette technique utilise la microscopie électronique à balayage, la microélectrolithographie, l’analyse d’image et des moyens d’essais mécaniques in situ. Si elle permet, en relation avec une analyse microstructurale, de mettre en évidence les différents mécanismes responsables de la plasticité et/ou de l’endommagement des matériaux, son utilisation quantitative en fait un outil essentiel de validation des modèles de prédiction de comportement, que ce soit à l’échelle locale ou à l’échelle macroscopique. Enfin, la connaissance du champ de déplacement expérimentalement mesuré permet d’améliorer sensiblement le résultat des simulations numériques par éléments finis par une meilleure prise en compte des conditions aux limites imposées sur le bord de la cellule modélisée. (10.1051/metal:2003110)
  DOI : 10.1051/metal:2003110
• Analysis of continental midcrustal strain localization induced by microfracturing and reaction-softening
  
  • Gueydan F.
  • Leroy Y. M.
  • Jolivet J.
  • Agard Philippe
  Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2003, 108 (B2), pp.2064. (10.1029/2001JB000611)
  DOI : 10.1029/2001JB000611