Publications

2011

• Monitoring micrometer-scale collagen organization in rat-tail tendon upon mechanical strain using second harmonic microscopy.
  
  • Goulam Houssen Yannick
  • Gusachenko Ivan
  • Schanne-Klein Marie-Claire
  • Allain Jean-Marc
  Journal of Biomechanics, Elsevier, 2011, 44 (11), pp.2047-52. We continuously monitored the microstructure of a rat-tail tendon during stretch/relaxation cycles. To that purpose, we implemented a new biomechanical device that combined SHG imaging and mechanical testing modalities. This multi-scale experimental device enabled simultaneous visualization of the collagen crimp morphology at the micrometer scale and measurement of macroscopic strain-stress response. We gradually increased the ultimate strain of the cycles and showed that preconditioning mostly occurs in the first stretching. This is accompanied by an increase of the crimp period in the SHG image. Our results indicate that preconditioning is due to a sliding of microstructures at the scale of a few fibrils and smaller, that changes the resting length of the fascicle. This sliding can reverse on long time scales. These results provide a proof of concept that continuous SHG imaging performed simultaneously with mechanical assay allows analysis of the relationship between macroscopic response and microscopic structure of tissues. (10.1016/j.jbiomech.2011.05.009)
  DOI : 10.1016/j.jbiomech.2011.05.009
• Measurement of relevant elastic and damping material properties in sandwich thick plates
  
  • Rébillat Marc
  • Boutillon Xavier
  Journal of Sound and Vibration, Elsevier, 2011, 330 (25), pp.6098-6121. An easy-to-implement method to measure relevant elastic and damping properties of the constituents of a sandwich structure, possibly with a heterogeneous core, is proposed. The method makes use of a one-point dynamical measurement on a thick-plate. The hysteretic model for each (possibly orthotropic) constituent is written generically as "E(1+jη)" for all mechanical parameters. The estimation method of the parameters relies on a mixed experimental/numerical procedure. The frequencies and dampings of the natural modes of the plate are obtained from experimental impulse responses by means of a high-resolution modal analysis technique. This allows for considerably more experimental data to be used. Numerical modes (frequencies, dampings, and modal shapes) are computed by means of an extended Rayleigh-Ritz procedure under the "light damping" hypothesis, for given values of the mechanical parameters. Minimising the differences between the modal characteristics yields an estimation of the values of the mechanical parameters describing the hysteretic behaviour. A sensitivity analysis assesses the reliability of the method for each parameter. Validations of the method are proposed by (a) applying it to virtual plates on which a finite-element model replaces the experimental modal analysis, (b) some comparisons with results obtained by static mechanical measurements, and (c) by comparing the results on different plates made of the same sandwich material. (10.1016/j.jsv.2011.07.015)
  DOI : 10.1016/j.jsv.2011.07.015
• Corrosion sous contrainte assistée par l'irradiation en milieu primaire d'un acier inoxydable austénitique
  
  • Le Millier Morgane
  • Calonne Olivier
  • Crépin Jérôme
  • Duhamel Cecilie
  • Fournier L.
  • Gaslain Fabrice
  • Héripré Eva
  • Pineau André
  • Vidalenc Y.
  , 2011, pp.97-102.
• A coupled Unscented Kalman Filter and modified Error in Constitutive Relation technique for structural dynamics identification
  
  • Alarcon Albert
  • Bodel Charles
  • Bonnet Marc
  , 2011, pp.2163-2168. This work arises from an industrial need for EDF (the French electric power company) to study the dynamics of complex structures, for which (noisy) measurements are used in an effort to alleviate the presence of Finite Element model uncertainties. Our work aims at formulating and implementing a strategy allowing optimal estimation of the structure dynamics and model parameters from available, imperfect, modelling and experimental information. One of the motivations of this work is to consider evolving model parameters. This introduces additional difficulties in the identification strategy, especially when evolution laws are a priori unknown. In the present work we propose a strategy to tackle with the above mentioned problem based in combining both the modified Error in Constitutive Relation (mECR) technique and the Unscented Kalman Filter (UKF). A numerical example of a reinforced concrete beam is presented to show how this strategy gives particularly good results to both locate and identify model errors such as structural damage and boundary conditions misspecification. Furthermore, we illustrate how this approach is adapted for the case of evolving damage with no prior knowledge of the evolution law.
• Système d'imagerie dynamique plasmonique et microscopique : application à l'étude de la motilité cellulaire
  
  • Moreau Julien
  • Allain Jean-Marc
  • Gulvady R.
  • Duval Aurélien
  • Bellemain Alain
  • Canva Michael
  , 2011.
• Modal energy transfer from geometrical nonlinearities in a tree-like structure
  
  • Theckes Benoît
  • de Langre Emmanuel
  • Boutillon Xavier
  , 2011, pp.2 p.. A modal energy transfer mechanism caused by geometrical nonlinearities is identified and characterized in a cantilever Y-shaped structure. Dynamical analysis of a simple two-degree-of-freedom model allow to assess the parameters regulating this mechanism. A numerical simulation of the dynamics of a finite-element model exhibits the same mechanism.
• Wave-based crack imaging in elastic solids using 3D time-domain topological sensitivity
  
  • Bellis Cédric
  • Bonnet Marc
  , 2011.
• Énergie: des solutions réalistes pour un développement durable ?
  
  • Salençon Jean
  Bulletin de l'Académie des Sciences et Lettres de Montpellier, Académie des Sciences et Lettres de Montpellier, 2011, 42, pp.302-323.
• Audio, visual, and audio-visual egocentric distance perception in virtual environments
  
  • Rébillat Marc
  • Boutillon Xavier
  • Corteel Etienne
  • Katz Brian F,g
  , 2011, pp.482. Previous studies have shown that in real environments, distances are visually correctly estimated. In visual (V) virtual environments (VEs), distances are systematically underestimated. In audio (A) real and virtual environments, near distances (< 2m) are overestimated whereas far distances (>2 m) are underestimated. However, little is known regarding combined A and V interactions on the egocentric distance perception in VEs. In this paper we present a study of A, V, and AV egocentric distance perception in VEs. AV rendering is provided via the SMART-I2 platform using tracked passive visual stereoscopy and acoustical wave field synthesis (WFS). Distances are estimated using triangulated blind walking under A, V, and AV conditions. Distance compressions similar to those found in previous studies are observed under each rendering condition. The audio and visual modalities appears to be of similar precision for distance estimations in virtual environments. This casts doubts on the commonly accepted visual capture theory in distance perception.
• Global and local synthetic descriptions of the piano soundboard
  
  • Ege Kerem
  • Boutillon Xavier
  , 2011 (000138), pp.473-478. Up to around 1.1 kHz, the soundboard of the piano behaves like a homogeneous plate whereas upper in frequency, it can be described as a set of waveguides defined by the ribs. In consequence: a) The acoustical coincidence phenomenon is deeply modified in comparison with that occurring in homogeneous plates since the dispersion curve of a waveguide can present none, one, or two coincidence frequencies. This may result in a nonuniformity of the soundboard radiation in the treble range, corresponding to the so-called killer octave, where a good sustain is difficult to obtain. b) The mobility (mechanical admittance) in the direction normal to the soundboard can be synthesised with only a small number of parameters. It compares well with published measurements (Giordano, JASA, 1998), in particular the step-like falloff of the local impedance due to the localisation of the waves between ribs. c) The synthesised mobility has the same features as those which can be derived independantly, according to Skudrzyk (JASA, 1980) and Langley (JSV, 1994). This approach avoids the detailed description of the soundboard, based on a very large number of parameters. It can be used to predict global changes of the driving point mobility, and possibly of the sound radiation in the treble range, resulting from structural modifications.
• Simultaneous reflection microscopy and surface plasmon resonance imagery: study on cell motility
  
  • Moreau Julien
  • Allain Jean-Marc
  • Gulvady R.
  • Duval Aurélien
  • Bellemain Alain
  • Canva Michael
  , 2011.
• From initiation of cracks to fatigue propagation: the interest of cohesive zone models
  
  • Marigo Jean-Jacques
  , 2011.
• Homogenized Interface Model Describing Inhomogeneities Periodically Distributed on a Surface
  
  • David Martin
  • Marigo Jean-Jacques
  • Pideri Catherine
  , 2011.
• Numerical Algorithm to Study the Stability of Damage Problems
  
  • Beaurain Jérôme
  • Marigo Jean-Jacques
  • Kazymyrenko Kyrylo
  , 2011.
• Damage approaches by thick level-set : analytical solutions and simulations
  
  • Stolz Claude
  • Moes Nicolas
  , 2011.
• Damage growth as an interface problem the thick level set approach
  
  • Bernard Paul Emile
  • Chevaugeon Nicolas
  • Moes Nicolas
  • Stolz Claude
  , 2011.
• Influence du procédé d'injection dans la simulation mécanique de thermoplastiques chargés en fibres de verre courtes
  
  • Launay Antoine
  • Maitournam Habibou
  • Marco Yann
  • Raoult Ida
  , 2011, pp.8 p. ; Clé USB. Les thermoplastiques renforcés en fibres de verre courtes présentent un comportement mécanique fortement non-linéaire lorsqu'ils sont soumis à des chargements cycliques, sous différentes conditions hygrothermiques. Une loi de comportement phénoménologique est proposée de façon à décrire différents mécanismes physiques, tells que la viscoplasticité, l'écrouissage ou l'adoucissement cyclique. La microstructure anisotrope, conséquence de la mise en forme par injection, est prise en compte dans le modèle par l'intermédiaire de tenseurs d'orientation.
• Comportement asymptotique des structures soumises à des chargements thermo-mécaniques cycliques
  
  • Benoit Aurélie
  • Maitournam Habibou
  • Rémy Luc
  • Oger Frédéric
  , 2011, pp.8 p.. Les structures soumises à des chargements cycliques présentent différents types de comportement asymptotique : l'adaptation, l'accommodation ou le rochet. Cette étude vise à caractériser ces différents comportements et à les identifier pour une structure soumise à des chargements thermomécaniques cycliques et dont le matériau possède des caractéristiques mécaniques variant avec la température. Les définitions proposées sont ensuite illustrées sur quelques cas simples.
• Glissement intermateriaux lors de simulations ALE en grandes déformations et grandes vitesses
  
  • Folzan Gauthier
  • Le Tallec Patrick
  • Perlat Jean-Philippe
  , 2011, pp.7 p. ; Clé USB. Lors de simulations de milieux multimatériaux en grandes déformations avec une méthode ALE, l'interface entre les matériaux peut se retrouver à l'intérieur des mailles de calcul. Il faut donc mettre en place une stratégie spécifique dans ces mailles mixtes. La méthode proposée, basée sur les éléments finis enrichis permet d'avoir un champ de vitesse propre à chaque matériau y compris dans les mailles mixtes. La réunion des différents champs de vitesse peut présenter une discontinuité sur l'interface ce qui donne la liberté nécessaire à la simulation du glissement entre les matériaux. See http://hal.archives-ouvertes.fr/docs/00/59/27/08/ANNEX/r_MF58LJ0L.pdf
• Modélisations quasi-continues du comportement dynamique d'un réseau atomique de simple micro-structure
  
  • Charlotte Miguel
  • Truskinovsky Lev
  , 2011, pp.8 p. ; Clé USB. Le comportement dynamique non-trivial d'une simple chaîne monoatomique linéairement élastique est homogénéisé/continualisé en tenant compte de ses propriétés dispersives. Celles-ci sont peu ou mal connues et violent l'interprétation de causalité d'Einstein dans le cas d'un domaine non-borné. Nous démontrons que ce comportement "granulaire" peut-être interprété, dans différentes modélisations continues, par la présence de pseudo-forces inertielles post-newtoniennes ignorées des couplages numériques multi-échelles qui se fondent sur une hypothétique décomposition hamiltonienne des énergies. See http://hal.archives-ouvertes.fr/docs/00/59/28/16/ANNEX/r_AR7IKB7D.pdf
• Magnetorheological Elastomers: Experiments and Modeling
  
  • Danas Kostas
  • Kankanala Sunny
  • Triantafyllidis Nicolas
  , 2011, pp.8 p. ; Clé USB. Magnetorheological elastomers (MREs) are ferromagnetic particle impregnated elastomers whose mechanical properties are altered by the application of external magnetic fields. Due to their magnetoelastic coupling response MREs are finding an increasing number of engineering applications. The objective of this work is : (a) the experimental study of transversely isotropic MREs (i.e., the particles form chains along a certain direction) that are subjected to prestressing and arbitrary magnetic fields and (b), the phenomenological modeling of these materials using transversely isotropic energy functions. See http://hal.archives-ouvertes.fr/docs/00/59/26/92/ANNEX/r_NHEKI0N4.pdf
• Approches par maillage conforme en mécanique non-linéaire de la rupture : méthode G-theta et modèle de zone cohésive
  
  • Chiaruttini Vincent
  • Guilie Joachim
  • Frédéric Feyel
  • Bonnet Marc
  • Le Tallec Patrick
  , 2011, pp.8 p. ; Clé USB. On présente deux approches pour la fissuration en élastoplasticité : l'une basée sur l'introduction d'une grandeur énergétique caractéristique de la fissuration pertinente dans ce contexte, l'autre associant remaillage adaptatif et prédiction de trajet de fissuration pour un modèle cohésif. Ces approches, mises en œuvre dans le code aux éléments finis Zset/Zebulon, sont évaluées sur des problèmes représentatifs simples. See http://hal.archives-ouvertes.fr/docs/00/59/29/29/ANNEX/r_905JKSQE.pdf
• Identification de fissures dans des milieux homogènes ou bimatériaux par sensibilité topologique élastodynamique temporelle
  
  • Bellis Cédric
  • Bonnet Marc
  , 2011, pp.7 p. ; Clé USB. Le concept de sensibilité topologique quantifie la perturbation induite à une fonction coût donnée lors de l'introduction d'un défaut infinitésimal dans un domaine sain de référence, et peut être uti- lisé pour définir une fonction indicatrice de défauts. Cette communication présente une extension de cette notion à l'identification 3D de fissures dans des solides homogènes ainsi qu'à l'interface de bimatériaux. Des simulations numériques élastodynamiques 3D montreront que cette formulation nouvelle permet une identification simple et fiable des emplacements et des orientations locales des fissures recherchées.
• Sur le mystère de la solution linéarisée pour détecter un défaut volumique
  
  • Bui Huy Duong
  , 2011, pp.Clé USB. See http://hal.archives-ouvertes.fr/docs/00/59/27/44/ANNEX/r_Y3CZM4FK.pdf
• Failure of elasto-plastic porous materials subjected to triaxial loading conditions
  
  • Danas Kostas
  • Ponte Castaneda Pedro
  , 2011, pp.2 p. ; Clé USB. This work makes use of the recently proposed second-order nonlinear homogenization model (SOM) for (visco)plastic porous materials [1] to study the influence of the Lode parameter and the stress triaxiality on the failure of metallic materials. This model is based on the "second-order" or "generalized secant" homogenization method [2] and is capable of handling general "ellipsoidal" microstructures (i.e., particulate microstructures with more general orthotropic overall anisotropy) and general three-dimensional loading conditions. See http://hal.archives-ouvertes.fr/docs/00/59/26/93/ANNEX/r_A1B5O25U.pdf