Publications

2003

• Identification de failles sismiques par une fonctionnelle de réciprocité généralisée
  
  • Bui Huy Duong
  • Constantinescu Andrei
  • Maigre Hubert
  , 2003, 1, pp.13-20.
• 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
• Mechanical constraints on the chronology of fracture activation in folded Devonian sandstone of the western Moroccan Anti-Atlas
  
  • Guiton M. L. E.
  • Sassi W.
  • Leroy Y. M.
  • Gauthier B. D. M.
  Journal of Structural Geology, Elsevier, 2003, 25, pp.1317-1330. The three-dimensional meter-scale fracture networks, observed on exposed folds between the towns of Tata and Akka, western Moroccan Anti-Atlas, consist mostly of planar discontinuities, which are sub-perpendicular to the bedding and partitioned in three main sets. The chronology of their activation is proposed in five stages since the Hercynian orogeny. Stage 1 predates folding and involves the horizontal compression of the Emsian sandstone. It involves fracture set I, composed of systematic joints parallel to the direction of compression. Stages 2–4 correspond to the folding and are marked in the outer-arc by the activation of fracture set II, composed mainly of joints parallel to the fold axial plane. Stage 5 is a regional shear event during which sets I and III, separated by an angle close to 60°, are activated in a conjugate manner. To throw light on the recurrent difficulty in discriminating between activation of inherited and new fractures, an elasto-plastic model is used to construct a stress path in the pervasively fractured medium idealized as a continuum. Each fracture set obeys the Mohr–Coulomb criterion truncated in tension to describe both sliding and opening activations. Finite-element simulations of a simple buckling event accounting for the field fracture sets are presented. It is shown that set I cannot be generated by folding and thus does belong to stage 1. Set II is activated at a later stage of folding than expected from the field interpretation. Set III cannot be activated during stage 2, confirming its role in stage 5. The advantages and limitations of the proposed modeling are finally discussed. (10.1016/S0191-8141(02)00155-4)
  DOI : 10.1016/S0191-8141(02)00155-4
• A shakedown analysis in hardening plasticity
  
  • Nguyen Quoc Son
  Journal of the Mechanics and Physics of Solids, Elsevier, 2003, 51, pp.101-125. The extension of classical shakedown theorems for hardening plasticity is interesting from both theoretical and practical aspects of the theory of plasticity. This problem has been much discussed in the literature. In particular, the model of generalized standard materials gives a convenient framework to derive appropriate results for common models of plasticity with strain-hardening. This paper gives a comprehensive presentation of the subject, in particular on general results which can be obtained in this framework. The extension of the static shakedown theorem to hardening plasticity is presented at first. It leads by min-max duality to the definition of dual static and kinematic safety coefficients in hardening plasticity. Dual static and kinematic approaches are discussed for common models of isotropic hardening, of limited or unlimited kinematic hardening. The kinematic approach also suggests for these models the introduction of a relaxed kinematic coefficient following a method due to Koiter. Some models for soils such as the Cam-clay model are discussed in the same spirit for applications in geomechanics. In particular, new appropriate results concerning the variational expressions of the dual kinematic coefficients are obtained. (10.1016/S0022-5096(02)00058-3)
  DOI : 10.1016/S0022-5096(02)00058-3
• 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
• 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
• 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.
• 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
• Bearing capacity of strip footings with horizontal confinement
  
  • Salençon Jean
  Comptes rendus de l’Académie des sciences. Série IIb, Mécanique, Elsevier, 2003, 331, pp.319-324. For a strip footing under axial loading, the bearing capacity is influenced by the presence of rigid walls confining the foundation soil. This problem is investigated within the framework of the theory of yield design, considering both a perfectly rough and a frictionless contact condition at the interfaces with the walls in the case of a purely cohesive soil. Upper bounds for the correction factor to be applied to the classical value of the bearing capacity are determined, as functions of the non-dimensional geometric parameter of the problem, through the kinematic approach, implementing virtual velocity fields inspired from the solution to the problem of inverted extrusion. In the perfectly rough case, it appears that the new upper bound is a significant improvement of those already available. A very simple relationship is established, which derives the upper bound for the frictionless walls from the upper bound for the rough walls. A general conclusion of the analysis is that, for the values of the geometric parameter that are likely to be encountered in practice, the increase in the bearing capacity due to the presence of the rigid walls remains very small. (10.1016/S1631-0721(03)00071-8)
  DOI : 10.1016/S1631-0721(03)00071-8
• 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
• 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
• Hydrostatic interaction of a wetting fluid and a circular crack in an elastic material
  
  • Feraille Fresnet Adélaïde
  • Bui Huy Duong
  • Ehrlacher Alain
  Mechanics of Materials, Elsevier, 2003, 35, pp.581-586. This paper focuses on a new analytical solution: the one of the hydrostatic-elastic problem for a wetting fluid inside a 3D penny shaped circular crack in an elastic infinite solid loaded in tension at infinity, when the vapor pressure and the variation of liquid mass can be neglected. With the surface tension phenomena, the liquid is near the crack tip and is generally in tension (negative pressure). (10.1016/S0167-6636(02)00281-8)
  DOI : 10.1016/S0167-6636(02)00281-8
• Analyse fréquentielle de la fatigue des structures
  
  • Moumni Ziad
  • Maitournam Habibou
  • Dang Van Ky
  , 2003, pp.191-198.
• Mechanical behaviour of polymer nanocomposites: a discrete simulation approach
  
  • Chabert E.
  • Gauthier R.
  • Dendievel R.
  • Chazeau Laurent
  • Cavaille J. Y.
  , 2003. No abstract provided
• Influence de la microstructure des alliages de zirconium sur leur sensibilité a la vitesse de déformation et a la température
  
  • Elbachiri K.
  • Crépin Jérôme
  • Rebeyrolle V.
  • Bretheau T.
  , 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
• 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
• 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
• Ondes de surface sous contact unilatéral et frottement de Coulomb
  
  • Nguyen Q. S.
  • Oueslati A.
  , 2003, pp.353-360 (tome 2). No abstract provided
• 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
• 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
• 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
• Stability and bifurcation with moving discontinuities
  
  • Stolz Claude
  • Pradeilles-Duval Rachel-Marie
  , 2003, pp.261-268. The propagation of moving surface inside a body is analysed in the framework of thermodynamics, when the moving surface is associated with an irreversible change of mechanical properties. The thermodynamical force associated to the propagation has the form of an energy release rate. Quasistatic rate boundary value problem is given when the propagation of the interface is governed by a normality rule. Extension to generalised media to study delamination is also investigated. (10.1007/0-387-26261-X_26)
  DOI : 10.1007/0-387-26261-X_26
• A study of cellular structures under impact loading
  
  • Abdennadher Salim
  • Zhao Han
  • Othman Ramzi
  , 2003. This paper presents the effect of inertia of cellular structures under impact loading. Experimental results under static and dynamic loading will be presented for square tubes made of a rate quasi-insensitive material (brass), the dynamic results being obtained using modified split Hopkinson pressure bar technique. The numeric simulation under Ls-dyna of those tests giving similar results will be also presented. Presented experimental, numeric results show that the inertia effect is a dominant factor responsible for the enhancement of crushing strength of cellular structures. (10.1051/jp4:20020733)
  DOI : 10.1051/jp4:20020733
• Modélisation du comportement dynamique d'une courroie de distribution
  
  • Bourgeois M.
  • Thomas J.-J.
  • Stolz Claude
  , 2003, pp.189-196 (tome 2). No abstract provided