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.
• Wave-based crack imaging in elastic solids using 3D time-domain topological sensitivity
  
  • Bellis Cédric
  • Bonnet Marc
  , 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.
• 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.
• 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
• Étude de la multifissuration e délamination par l'approche variationnelle à la mécanique de la fracture
  
  • León Baldelli Andrés Alessandro
  • Bourdin Blaise
  • Marigo Jean-Jacques
  • Maurini Corrado
  , 2011, pp.8 p. ; Clé USB. Cette article traite de la fissuration transverse et délamination de couches minces par l'approche variationnelle à la mécanique de la rupture. La disposition des fissures et des zones délaminées est obtenue suivant un principe de minimisation. Les résultats analytiques en 1D, ainsi que ceux numériques obtenus par approximation avec des modèles d'endommagement permettent de retrouver les évidences expérimentales de périodicité des fissures et symétrie des domaines de délamination. See http://hal.archives-ouvertes.fr/docs/00/59/28/09/ANNEX/r_16IGUK76.pdf
• Analyse de stabilité d'une nappe fibrée en compression
  
  • Lignon Eric
  • Le Tallec Patrick
  • Triantafyllidis Nicolas
  , 2011, pp.8 p. ; Clé USB. L'objectif de ce travail est de modéliser le flambement de nappes fibrées lorsque les câbles sont soumis à une compression axiale. Nous réalisons une analyse de stabilité multi- échelles basée sur le résultat de [1], qui permet de réduire le problème à une cellule élémentaire 2D et de modéliser les modes propres sous forme d'ondes de Bloch. Nous avons choisi de nous placer dans le cas particulier d'une flexion circulaire, mais la méthode proposée est valable pour des chargement plus généraux.
• A method to measure elastic and dissipative material properties of sandwich structures and its numerical validation
  
  • Rébillat Marc
  • Boutillon Xavier
  , 2011, pp.8 p. ; Clé USB. A method to measure elastic and dissipative properties of the constituents of a sandwich structure is proposed and validated. The method relies on the comparison between (a) the modal frequen- cies and dampings of a thick plate as predicted by an extended Rayleigh-Ritz procedure and (b) the their values as given by experimentation or numerical simulation. On real plates, a one-point measurement of free vibrations is sufficient, provided that a high-resolution modal analysis [1] is used [2]. For valida- tion purposes, the experimental modal analysis is replaced by a finite-element model analysis (numerical measurement). Minimising the differences between the modal characteristics yields an estimation of the values of the elastic and dissipative material properties. Agreement between estimated and original mechanical parameters is shown to be good for the parameters which are influential in plate vibration. See http://hal.archives-ouvertes.fr/docs/00/59/28/82/ANNEX/r_0PBFPY04.pdf
• Mise en place d'un modèle de zone cohésive à base physique dans un bicristal de gamma-TiAl
  
  • Geoffroy Dominique
  • Chiaruttini Vincent
  • Crépin Jérôme
  • Héripré Eva
  • Roos Arjen
  , 2011, pp.8 p.. Ces travaux proposent d'étudier numériquement l'effet d'une fissure intragranulaire modélisée par des éléments cohésifs dans un bicristal de γ-TiAl. Les effets de la fissure, insérée dans le premier grain, sont étudiés dans le second grain à la suite d'un calcul de traction monotone en plasticité cristalline. Des critères de fissuration intragranulaire fonction de la déformation plastique équivalente induite par les macles sont étudiés afin de prédire la rupture du bicristal. L'état de contrainte normal au joint de grains est ensuite examiné afin d'évaluer la compétition entre la rupture intergranulaire et intragranulaire. See http://hal.archives-ouvertes.fr/docs/00/59/29/23/ANNEX/r_7L09K124.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