Publications

2014

• FLUAGE DU SEL GEMME SOUS CHARGEMENT CYCLIQUE
  
  • Djizanne Hippolyte
  • Valli Pierre
  , 2014. Dans le cadre du projet SACRE (Stockage d'Air Comprimé pour le Réseau Electrique) du programme STOCK-E 2010 (Stockage innovant de l'énergie) de l'Agence Nationale de la Recherche (ANR), des essais mécaniques sont réalisés sur des éprouvettes de sel gemme au Laboratoire de Mécanique des Solides (LMS) à l'Ecole Polytechnique. L'objectif de ces essais est de mieux comprendre le fluage en extension du sel sous chargement cyclique. Le comportement rhéologique du sel est supposé élasto-viscoplastique et très sensible aux variations de température. Le choix de faire des essais en extension au cours desquels la pression de confinement est supérieure à la force axiale est argumenté. La méthode expérimentale, les matériaux et les équipements utilisés sont décrits ; quelques résultats sont ensuite interprétés et enfin les difficultés rencontrées et les perspectives scientifiques sont présentées.
• The out-of-plane deformation in pure aluminium oligocrystal and its influence on thermographic measurement
  
  • Wang X.G
  • Witz Jean-Francois
  • El Bartali Ahmed
  • Dufrenoy Philippe
  • Charkaluk E.
  , 2014.
• 3D strain patterning in polycristalline halite
  
  • Ababacar Gaye
  • Bornert Michel
  • Dimanov Alexandre
  • Ludwig Wolfgang
  • Bourcier M.
  • Gharbi H.
  • Héripré Eva
  • Picard D.
  • Raphanel Jean
  • Sab Karam
  , 2014.
• Atomistic Level Simulations of the Effect of Filler Particle Size on the Properties of Nanocomposites
  
  • Brown D.
  • Marcadon V.
  • Mele P.
  • Hervé E.
  • Zaoui A.
  • Albérola N. D.
  , 2014.
• Multiscale investigation of ductile fracture mechanisms and strain localization under shear loading in 2024-T351 aluminum alloy and 36NiCrMo16 steel
  
  • Papasidero Jessica
  • Doquet Véronique
  • Lepeer Sebastien
  Materials Science and Engineering: A, Elsevier, 2014. Ductile fracture mechanisms under shear loading have been investigated in 2024-T351 aluminum alloy and 36NiCrMo16 steel through interrupted torsion tests followed by SEM observations and through direct monitoring of damage during in situ torsion tests in a SEM. Strain localization was observed at meso-scale, but also at micro-and sub-grain scale. A significant axial elongation was measured in both materials during the torsion tests. This " Swift effect " might partly explain why in the aluminum alloy most voids elongate in one direction and shrink in the orthogonal one but do not completely collapse and why some voids even grow. The crystallographic texture and its evolutions – quite significant in the ductile 36NiCrMo16 steel – play a significant role. No void nucleation was observed in steel. Microcracks initiated at an early stage but did not grow up to a large shear strain. Due to some reorientations, clusters of grains sharing the same orientation appeared. This favored shear bands development and microcracks growth. & (10.1016/j.msea.2014.05.032)
  DOI : 10.1016/j.msea.2014.05.032
• Reconstruction of elastic moduli from noisy full-field measurements
  
  • G. Bal
  • Bellis Cédric
  • Imperiale Sebastien
  • Monard François
  , 2014. no abstract
• High order theta schemes for linear wave equation
  
  • Chabassier Juliette
  • Imperiale S.
  , 2014, pp.1-2.
• Modeling and simulating the dynamics of the grand piano action
  
  • Thorin Anders
  • Boutillon Xavier
  • Lozada José
  • Merlhiot Xavier
  , 2014. The grand piano action has been developed empirically over two centuries. In its modern version, it provides a remarkably accurate control of the hammer velocity and its impact time. By means of an elementary 1-DOF model, we show why it is mostly preferable to consider and simulate the dynamics by computing the reaction force in response to a motion imposed by the finger rather than the opposite. We present a complete dynamical model based on that proposed earlier by Lozada: 6 rotating bodies (key, damper, whippen, jack, escapement lever, hammer), pivots subject to dry and viscous friction, 13 contact zones with reacting and dissipative forces, 3 of them (hammer-jack, jack-escapement button, hammer-check) being also subject to Coulomb friction. This model introduces discontinuities on the velocities. The problems raised by the usual regular-dynamics formulation are discussed and a non-smooth dynamics approach is proposed. The results of the numerical simulation of the model are in very good agreement with the measurements for levels of playing ranging from piano to forte.
• Microtomographie, essais in situ et mesures de champs volumiques
  
  • Bornert Michel
  • Lenoir Nicolas
  • Bruchon J.-F.
  • Pereira Jean-Michel
  • Vandamme Matthieu
  • Delage Pierre
  • Caré Sabine
  • Chateau Camille
  • Nguyen T.T.
  , 2014.
• Probabilistic thermal-mechanical fatigue criterion for lost foam casting aluminium alloys based on 2D/3D porosities distribution
  
  • Szmytka F.
  • Limodin N.
  • Wang L.
  • Osmond P.
  • Adrien J.
  • Charkaluk E.
  • Buffiere Jean-Yves
  , 2014, 12. (10.1051/matecconf/20141205005)
  DOI : 10.1051/matecconf/20141205005
• Coupling of experimental measurements to study the influence of microscopic defects on the fatigue damage in A319 Al-Si alloy
  
  • Wang Long
  • Limodin Nathalie
  • Bartali Ahmed El
  • Charkaluk Eric
  • Buffiere Jean-Yves
  , 2014, 12. (10.1051/matecconf/20141204012)
  DOI : 10.1051/matecconf/20141204012
• Influence of crosslinking and plasticizing on the viscoelasticity of highly filled elastomers
  
  • Azoug Aurélie
  • Nevière Robert
  • Pradeilles-Duval Rachel-Marie
  • Constantinescu Andrei
  Journal of Applied Polymer Science, Wiley, 2014, 131 (12), pp.40392-1-9. Solid propellants, like all highly filled elastomers, exhibit a complex nonlinear viscoelastic behavior. The aim of this study was to establish the relationships between the structure and properties, which is needed to construct a robust constitutive law for these materials. An extensive design of experiments approach allowed us to quantify the influence of the curing agents and plasticizer molecules on the microstructure of the propellant and its viscoelastic properties. Swelling and gel permeation chromatography measurements described the microstructure of the propellant and prestrained dynamic mechanical analysis (PDMA) characterized the viscoelastic behavior. The curing agents reacted with polymer chain ends participating in the network, in the sol fraction, or in filler–binder links. Consequently, the polymer network was incomplete even in stoichiometric conditions, and a minimum of 10% of the polymer was free in the microstructure. In addition, preswelling the polymer with plasticizer molecules before curing modified the obtained network by decreasing the crosslink density in the binder and increasing it in the vicinity of the filler surface. This study provided new insight into the local deformation mechanisms controlling nonlinearity as measured by PDMA. The nonlinear behavior appeared between 0 and 1.7% prestrain in both the elastic and viscous parts of the behavior. The network reached its maximum extensibility in the elastic part and constrained the sol fraction in this extended mesh for the viscous part. (10.1002/app.40392)
  DOI : 10.1002/app.40392
• Micromechanicals of halite investigated by 2D and 3D multiscale full field measurements, 48th US Rock Mechanics
  
  • Ababacar Gaye
  • Bornert Michel
  • Lenoir Nicolas
  • Sab Karam
  • Dimanov A.
  • Bourcier M.
  • Héripré E.
  • Raphanel Jean
  • Gharbi H.
  • D. Picard
  • Ludwig Wolfgang
  , 2014. The deformation of synthetic halite is investigated at the scale of its polycrystalline microstructure. Images recorded during compression test performed in the chamber of a scanning electron microscope on centimeter sized samples are analyzed by Digital Image Correlation techniques and reveal the combined contribution of crystal slip plasticity and grain boundary sliding (GBS) and opening. Specifically developed processing routines allow us to quantify the relative contributions of both mechanisms to the overall strain, and their dependences with temperature. These surface measurements are complemented by full 3D analyses based on synchrotron X-Ray absorption computed tomography on similar samples. The analysis of the CT volumes at various load levels by Digital Volume Correlation routines, confirms the complex localization of deformation at the scale of the microstructure. Transverse cracks at grain boundaries are also observed in the bulk of the material, as indirect signs of GBS.
• Hydro-mechanical properties of chemically altered limestones using 2D and 3D full-field multi-scale investigations
  
  • Dimanov A.
  • Zinsmeister L.
  • Dautriat J.
  • Gland N.
  • Bornert Michel
  • Raphanel J.
  , 2014.
• Investigation of the work hardening stages of nickel single crystals from full-field strain measurements
  
  • Wang X.G
  • Oudriss Abdelali
  • El Bartali Ahmed
  • Witz Jean-Francois
  • Seghir Rian
  • Dufrenoy Philippe
  • Feaugas Xavier
  • Charkaluk Eric
  , 2014.
• Computational fretting fatigue maps for different plasticity models
  
  • Alquezar-Getan Marcel
  • Arrieta Victor Hernan
  • Constantinescu Andrei
  • Flandi Leïla
  • Maitournam Habibou
  • Wackers Patrick Yves
  Fatigue and Fracture of Engineering Materials and Structures, Wiley-Blackwell, 2014, 37 (4). This paper presents qualitative elastoplastic simulations and analyses of fretting fatigue. Three hardening constitutive models are considered, and their effects on stick–slip conditions and lifetime prediction are compared. The computational analysis consists of the estimation of the shakedown limit cycle and the fatigue prediction using Dang Van or Crossland criterion. A particular configuration, the interaction of a flat pad with rounded corners in contact with a flat substrate made, respectively, of Inconel In718 and Titanium Ti64 alloys, is studied. The shakedown state is analysed using the cyclic and ratcheting equivalent strain concepts already discussed in the literature. In the paper, different fretting maps, based on slip, shakedown and fatigue regimes, are numerically produced and analysed. A new variable, the global slip percentage, is proposed for the characterization of the stick–slip regimes. Analyses of a series of slip maps show that the different hardening models do not introduce significant changes in the stick–slip conditions. Using finite element method simulations combined with fatigue limit criteria (Dang Van and Crossland), fretting fatigue maps are qualitatively reproduced. The main contribution of this work is a comparative discussion on the influence of the hardening models complexity on such maps. (10.1111/ffe.12130)
  DOI : 10.1111/ffe.12130
• Shear strength of rock discontinuities reinforced by passive rockbolt, Proc. International Conference on Rock Slope Stability (RSS 2014), Marrakech, Morocco.
  
  • Pellet Frederic
  • Maiolino S.
  , 2014.
• Formulation of gradient multiaxial fatigue criteria
  
  • Luu Duy-Hao
  • Maitournam Habibou
  • Nguyen Q. S.
  International Journal of Fatigue, Elsevier, 2014, 61, pp.170–183. A formulation of gradient fatigue criteria is proposed in the context of multiaxial high-cycle fatigue (HCF) of metallic materials. The notable dependence of fatigue limit on some common factors not taken into account in classical fatigue criteria, is analyzed and modeled. Three interconnected factors, the size, stress gradient and loading effects, are here investigated. A new class of fatigue criteria extended from classical ones with stress gradient terms introduced not only in the normal stress but also in the shear stress components, is formulated. Such a formulation allows to capture gradient effects and related “size” effects, as well as to cover a wide range of loading mode, then can model both phenomena “Smaller is Stronger” and “Higher Gradient is Stronger”. Gradient versions of some classical fatigue criteria such as Crossland and Dang Van are provided as illustrations. (10.1016/j.ijfatigue.2013.11.014)
  DOI : 10.1016/j.ijfatigue.2013.11.014
• The force of impacting rain
  
  • Soto Dan
  • Borel de Larivière Aurélie
  • Boutillon Xavier
  • Clanet Christophe
  • Quéré David
  Soft Matter, Royal Society of Chemistry, 2014, 27 (july), pp.4929-4934. Drop impacts are difficult to characterize due to their transient, non-stationary nature. We discuss the force generated during such impacts, a key quantity for animals, plants, roofs or soil erosion. Although a millimetric drop has a modest weight, it can generate collision forces on the order of thousand times this weight. We measure and discuss this amplification, considering natural parameters such as drop radius and density, impact speed and response time of the substrate. We finally imagine two kinds of devices allowing us to deduce the size of the raindrop from impact forces. (10.1039/C4SM00513A)
  DOI : 10.1039/C4SM00513A
• Comportement à la rupture et caractérisation mécanique des caoutchoucs cristallisants sous contrainte
  
  • Guilie Joachim
  , 2014. L'objet du travail exposé dans ce mémoire de thèse de Doctorat est d'obtenir une loi de comportement anisotrope représentative de la cristallisation sous contrainte dans le caoutchouc, de l'intégrer dans un calcul macroscopique éléments finis, et de comprendre l'influence de ce phénomène sur la propagation de fissures dans ce matériau par un critère de taux de restitution d'énergie. Le problème modèle qui motive cette étude est celui de l'endurance des pneumatiques. Après une introduction générale des difficultés qui se posent dans l'endurance des pneumatiques, nous rappelons en première partie quelques notions essentielles sur le cadre mécanique. La partie II est l'occasion de s'intéresser au cadre de calcul du taux de restitution d'énergie par des méthodes de dérivation par rapport au domaine. Nous proposons alors une extension formelle de ce type de méthode au cas du comportement viscoplastique. Cette extension est proposée dans un premier cas où les processus dissipatifs et le processus de rupture sont découplés. Elle est alors testée et validée par différences finies sur des cas de calculs élastoplastiques. On propose ensuite une méthode de calcul du taux de restitution d'énergie dans le cas couplé par un état adjoint. Cette méthode est testée sur un problème viscoélastique simple. Dans la partie III, on se propose de construire une loi de comportement constitutive de la cristallisation sous contrainte. Le point de départ est une analyse microscopique que l'on passe à l'échelle macroscopique dans le cadre du modèle de micro-sphère qui nous permet de caractériser la relation contrainte-déformation, l'anisotropie des réponses locales et les effets localement induits par la cristallisation en fond de fissure. Cette construction se fonde sur des observations expérimentales de base en insistant sur les aspects constitutifs du comportement cyclique. La loi obtenue est ensuite comparée à plusieurs mesures expérimentales sur un panel exhaustif de chargements. Cela nous permet de montrer une bonne reproductibilité des résultats expérimentaux notamment en ce qui concerne les chargements cycliques et l'évolution de l'anisotropie. Pour finir, la partie IV aborde le problème de l'impact de la cristallisation sur la rupture du caoutchouc par les méthodes proposées dans les deux parties précédentes. On montre alors qu'on peut obtenir un profil de fissure et une zone cristallisée très semblable à ceux obtenus expérimentalement. De plus, l'extension du taux de restitution d'énergie proposée est appliquée à une éprouvette Pure Shear présentant de la cristallisation. L'évolution du taux de restitution d'énergie avec le chargement appliqué à l'éprouvette est alors comparée à l'évolution de la vitesse de propagation en fatigue.
• Identification of artery wall stiffness: in vitro validation and in vivo results of a data assimilation procedure applied to a 3D fluid-structure interaction model
  
  • Bertoglio Cristobal
  • Barber David
  • Gaddum Nicholas
  • Valverde Israel
  • Rutten Marcel
  • Beerbaum Philipp
  • Moireau Philippe
  • Hose Rodney
  • Gerbeau Jean-Frédéric
  Journal of Biomechanics, Elsevier, 2014, 47 (5), pp.1027–1034. We consider the problem of estimating the stiffness of an artery wall using a data assimilation method applied to a 3D fluid-structure interaction (FSI) model. Recalling previous works, we briefly present the FSI model, the data assimilation procedure and the segmentation algorithm. We present then two examples of the procedure using real data. First, we estimate the stiffness distribution of a silicon rubber tube from image data. Second, we present the estimation of aortic wall stiffness from real clinical data. (10.1016/j.jbiomech.2013.12.029)
  DOI : 10.1016/j.jbiomech.2013.12.029
• Couplages hydromécaniques dans les roches argileuses : analyse par microscopie électronique environnementale et corrélation d'images
  
  • Wang L.
  • Bornert Michel
  • Chanchole S.
  • Héripré Eva
  , 2014.
• Cyclic plasticity in duplex stainless steel
  
  • Seghir Rian
  • Bartali Ahmed El
  • Witz Jean-Francois
  • Dufrenoy Philippe
  • Charkaluk Eric
  , 2014.
• Matched asymptotic expansion method for an homogenized interface model
  
  • Geymonat Giuseppe
  • Hendili Sofiane
  • Krasucki Francoise
  • Vidrascu Marina
  Mathematical Models and Methods in Applied Sciences, World Scientific Publishing, 2014, 24 (3), pp.573-597. Our aim is to demonstrate the effectiveness of the matched asymptotic expansion method in obtaining a simpli ed model for the influence of small identical heterogeneities periodically distributed on an internal surface on the overall response of a linearly elastic body. The results of some numerical experiments corroborate the precise identi cation of the di fferent steps, in particular of the outer/inner regions with their normalized coordinate systems and the scale separation, leading to the model. (10.1142/S0218202513500607)
  DOI : 10.1142/S0218202513500607
• Experimental determination of a representative texture and insight into the range of significant neighboring grain interactions via orientation and misorientation statistics
  
  • Bodelot Laurence
  • Ravichandran Guruswami
  International Journal of Materials Research, 2014.