Publications

2008

• Identification of non-parametric probabilistic models from measured transfer functions
  
  • Arnst M.
  • Clouteau Didier
  • Bonnet Marc
  Computer Methods in Applied Mechanics and Engineering, Elsevier, 2008, 197, pp.589-608. This paper addresses the inversion of probabilistic models for the dynamical behaviour of structures using experimental data sets of measured frequency-domain transfer functions. The inversion is formulated as the minimization, with respect to the unknown parameters to be identified, of an objective function that measures a distance between the data and the model. Two such distances are proposed, based on either the loglikelihood function, or the relative entropy. As a comprehensive example, a probabilistic model for the dynamical behaviour of a slender beam is inverted using simulated data. The methodology is then applied to a civil and environmental engineering case history involving the identification of a probabilistic model for ground-borne vibrations from real experimental data. (10.1016/j.cma.2007.08.011)
  DOI : 10.1016/j.cma.2007.08.011
• Sur le problème d'évolution de fissure en élastoplasticité : approches primale et duale
  
  • Stolz Claude
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2008 (336), pp.500-505. Abstract We study the rate boundary value problem concerning crack propagation in an elastoplastic material. The formulation is given when the criterium of propagation is based on a energy release rate. Primal and dual approaches of the boundary value problem of evolution are proposed. To cite this article: C. Stolz, C. R. Mecanique 336 (2008). Résumé La formulation du problème en vitesse de fissure et de déplacement est discutée lorsque le critère de propagation est fondé sur l'analyse de la dissipation. On se place alors dnas le cas de critère énergétique comme proposé (Nguyen, 1985) et généralisé récemment au cas des matériaux élastoplastiques (Stolz, 2008). On obtient alors les formulations primale et duale du problème d'évolution de la propagation de la fissure en élastoplasticité. Pour citer cet article : C. Stolz, C. R. Mecanique 336 (2008). Mots-clés: (10.1016/j.crme.2008.03.005)
  DOI : 10.1016/j.crme.2008.03.005
• MECHANICAL PROPERTIES OF GLENOID CANCELLOUS BONE
  
  • Kalouche Ibrahim
  • Abdelmoumen Samir
  • Crepin Jerome
  • Mitton David
  • Guillot Geneviève
  • Gagey Olivier
  Journal of Biomechanics, Elsevier, 2008, 41, pp.S 324.
• Comportement mécanique à très long terme des mines et cavernes dans le sel gemme : loi de Norton-Hoff ou loi de Lemaître ?
  
  • Berest Pierre
  • Bérest P.
  • Karimi-Jafari Mehdi
  • Brouard Benoît
  Revue française de Géotechnique, edp sciences, 2008 (124), pp.45-59.
• Conception d'un algorithme de calcul du risque de chute de la personne âgée
  
  • Thibaud Marie
  • Bloch Frédéric
  • Brèque Cyril
  • Kemoun Gilles
  , 2008.
• A multi-level fast-multipole multi-region method for 3-D frequency-domain elastodynamics
  
  • Chaillat Stéphanie
  • Semblat Jean-François
  • Bonnet Marc
  , 2008.
• L'effondrement de 1873 à la mine de Varangéville
  
  • Berest Pierre
  • Bérest P.
  , 2008, pp.281-288.
• Interpretation of Mechanical Integrity Tests
  
  • Berest Pierre
  • Bérest P.
  , 2008, pp.1263-1270.
• Biaxial Testing of Sheet Materials at High Strain Rates Using Viscoelastic Bars
  
  • Grolleau Vincent
  • Gary Gérard
  • Mohr Dirk
  Experimental Mechanics, Society for Experimental Mechanics, 2008, 48 (3), pp.293-306. A dynamic bulge testing technique is developed to perform biaxial tests on metals at high strain rates. The main component of the dynamic testing device is a movable bulge cell which is directly mounted on the measuring end of the input bar of a conventional split Hopkinson pressure bar system. The input bar is used to apply and measure the bulging pressure. The experimental system is analyzed in detail and the measurement accuracy is discussed. It is found that bars made of low impedance materials must be used to achieve a satisfactory pressure measurement accuracy. A series of dynamic experiments is performed on aluminum 6111-T4 sheets using viscoelastic nylon bars to demonstrate the capabilities of the proposed experimental technique. The parameters of the rate-dependent Hollomon–Cowper–Symonds J2 plasticity model of the aluminum are determined using an inverse analysis method in conjunction with finite element simulations. (10.1007/s11340-007-9073-5)
  DOI : 10.1007/s11340-007-9073-5
• Theoretical and numerical modeling of solid-solid phase change: Application to the description of the thermodynamical behaviour of shape memory alloys
  
  • Moumni Ziad
  • Zaki Wael
  • Nguyen Quoc Son
  International Journal of Plasticity, Elsevier, 2008, 24 (xx), pp.614-645. The mechanical behaviour of a solid capable of undergoing internal phase change is considered. Reversible and dissipative constitutive equations are established within the framework of generalized standard materials with internal constraints. The constraints are accounted for using Lagrange multipliers. The presented model is based upon a phenomenological configuration in series (Reuss model). In the case of reversible phase change, it is shown that the elastic energy of the material can be obtained by convexification the energy functions of existing phases. In the dissipative case, it is shown how the behaviour of the material can be made stable by developing evolving equations from a suitable dissipation potential. As an application, a description of the thermomechanical behaviour of shape memory alloys (SMAs). The obtained constitutive equations can be used to simulate the pseudoelastic response of SMAs as well as the one-way shape memory effect. Validation against experimental data is performed in the case of multiaxial thermomechanical loading for NiTi and Cu-based alloys. (10.1016/j.ijplas.2007.07.007)
  DOI : 10.1016/j.ijplas.2007.07.007
• Refined finite element modelling for the vibration analysis of large rotating machines
  
  • Combescure Didier
  • Lazarus Arnaud
  Journal of Sound and Vibration, Elsevier, 2008, 318. This paper is aimed at presenting refined finite element modelling used for dynamic analysis of large rotating machines. The first part shows an equivalence between several levels of modelling: firstly, models made of beam elements and rigid disc with gyroscopic coupling representing the position of the rotating shaft in an inertial frame; secondly full three-dimensional (3D) or 3D shell models of the rotor and the blades represented in the rotating frame and finally two-dimensional (2D) Fourier model for both rotor and stator. Simple cases are studied to better understand the results given by analysis performed using a rotating frame and the equivalence with the standard calculations with beam elements. Complete analysis of rotating machines can be performed with models in the frames best adapted for each part of the structure. The effects of several defects are analysed and compared with this approach. In the last part of the paper, the modelling approach is applied to the analysis of the large rotating shaft part of the power conversion unit of the GT-MHR nuclear reactor. (10.1016/j.jsv.2008.04.025)
  DOI : 10.1016/j.jsv.2008.04.025
• Éléments d'acoustique linéaire
  
  • Boutillon Xavier
  , 2008.
• A homogenization-based constitutive model for isotropic viscoplastic porous media
  
  • Danas Kostas
  • Idiart Martin I.
  • Ponte Castañeda Pedro
  International Journal of Solids and Structures, Elsevier, 2008, 45, pp.3392-3409. An approximate model based on the "second-order" nonlinear homogenization method is proposed to estimate the effective behavior of isotropic, viscoplastic, porous materials. The model is constructed in such a way that it reproduces exactly the behavior of a "composite-sphere assemblage" in the limit of hydrostatic loadings, and therefore coincides with the hydrostatic limit of Gurson's criterion in the special case of ideal plasticity. As a consequence, the new model improves on earlier homogenization estimates, which have been found to be quite accurate for low triaxialities but overly stiff for sufficiently high triaxialities and nonlinearities. Additionally, the estimates delivered by the model exhibit a dependence on the third invariant of the macroscopic stress tensor, which has a nontrivial effect on the effective response of the material at moderate triaxialities. The proposed model is compared with exact results obtained for a special class of porous materials with sequentially laminated microstructures. The agreement is found to be quite good for the entire range of stress triaxialities, and all values of the porosity and nonlinearity considered. (10.1016/j.ijsolstr.2008.02.007)
  DOI : 10.1016/j.ijsolstr.2008.02.007
• Intégrale duale en mécanique de la rupture.
  
  • Stolz Claude
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2008 (336), pp.434-439. We propose a dual approach in fracture mechanics based on complementary energy. The analysis of the dissipation shows that the thermodynamical force associated with the evolution of a crack is an energy release rate, form of which depends on the presence or not of mechanical discontinuities. This energy release rate is given as an integral based on free or complementary energy. We analyse the invariance of such integrals and we discuss the obtained results in elastoplasticity. Résumé On propose une intégrale duale en mécanique de la rupture ductile fondée sur l'énergie complémentaire. L'analyse de la dissipation mécanique en présence ou non de discontinuités mobiles montre que le paramètre énergétique associé à la vitesse de propagation est représenté par une intégrale de contour appropriée exprimée en terme d'énergie libre ou d'énergie complémentaire. On étudie alors l'invariance par rapport au contour de ces intégrales et on interpréte les résultats obtenus. (10.1016/j.crme.2008.02.002)
  DOI : 10.1016/j.crme.2008.02.002
• A fast multipole accelerated BEM for 3-D elastic wave computation
  
  • Chaillat Stéphanie
  • Bonnet Marc
  • Semblat Jean-François
  Revue Européenne de Mécanique Numérique/European Journal of Computational Mechanics, Hermès / Paris : Lavoisier, 2008, 17, pp.701-712. The solution of the elastodynamic equations using boundary element methods (BEMs) gives rise to fully-populated matrix equations. Earlier investigations on the Helmholtz and Maxwell equations have established that the Fast Multipole (FM) method reduces the complexity of a BEM solution to $N \log_{2}N$ per GMRES iteration. The present article addresses the extension of the FM-BEM strategy to 3D elastodynamics in the frequency domain. Efficiency and accuracy are demonstrated on numerical examples involving up to $N=O(10^{6})$ boundary nodal unknowns. (10.3166/remn.17.701-712)
  DOI : 10.3166/remn.17.701-712
• Optimal control approach in non linear mechanics
  
  • Stolz Claude
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2008, 336, pp.238-244. The purpose of this article is to present some applications of optimal control theory for non linear mechanical problems. In particular we consider some inverse problems dealing with the determination of unknown boundary conditions, the determination of internal state resulting of unknown loading history. Extensions to asymptotic behavior due to cyclic loading are also presented. (10.1016/j.crme.2007.11.015)
  DOI : 10.1016/j.crme.2007.11.015
• Subsidence, sinkholes and craters above salt caverns
  
  • Berest Pierre
  • Bérest P.
  , 2008, pp.269-278.
• Dynamic fracture: an example of convergence towards a discontinuous quasi-static solution
  
  • Dumouchel Pierre-Emmanuel
  • Marigo Jean-Jacques
  • Charlotte M.
  Continuum Mechanics and Thermodynamics, Springer Verlag, 2008, 20, pp.1-19. Considering a one-dimensional problem of debonding of a thin film in the context of Griffith's theory, we show that the dynamical solution converges, when the speed of loading goes down to 0, to a quasistatic solution including an unstable phase of propagation. In particular, the jump of the debonding induced by this instability is governed by a principle of conservation of the total quasistatic energy, the kinetic energy being negligible. (10.1007/s00161-008-0071-3)
  DOI : 10.1007/s00161-008-0071-3
• Topological sensitivity and FMM-accelerated BEM applied to 3D acoustic inverse scattering
  
  • Nemitz N.
  • Bonnet Marc
  Engineering Analysis with Boundary Elements, Elsevier, 2008, 32, pp.957-970. This study is set in the framework of inverse scattering of scalar (e.g. acoustic) waves. A qualitative probing technique based on the distribution of topological sensitivity of the cost functional associated with the inverse problem with respect to the nucleation of an infinitesimally-small hard obstacle is formulated. The sensitivity distribution is expressed as a bilinear formula involving the free field and an adjoint field associated with the cost function. These fields are computed by means of a boundary element formulation accelerated by the Fast Multipole method. A computationally fast approach for performing a global preliminary search based on the available overspecified boundary data is thus defined. Its usefulness is demonstrated through results of numerical experiments on the qualitative identification of a hard obstacle in a bounded acoustic domain, for configurations featuring $O(10^{5})$ nodal unknowns and O(10^{6})$ sampling points. (10.1016/j.enganabound.2007.02.006)
  DOI : 10.1016/j.enganabound.2007.02.006
• A New Experimental Technique for the Multi-axial Testing of Advanced High Strength Steel
  
  • Mohr Dirk
  • Oswald M.
  Experimental Mechanics, Society for Experimental Mechanics, 2008, pp.65-77.
• Large Deformation of Anisotropic Austenitic Stainless Steel Sheets at Room Temperature: Multi-axial Experiments and Phenomenological Modeling
  
  • Mohr Dirk
  • Jacquemin Johan
  Journal of the Mechanics and Physics of Solids, Elsevier, 2008, pp.2935-2956.
• Instruments à cordes frottées
  
  • Boutillon Xavier
  , 2008, pp.511-532 et 132-135.
• Combined shape-material sensitivity for elastic-wave identification of penetrable inclusions
  
  • Bonnet Marc
  • Guzina B. B.
  , 2008.
• Travelling interface waves in a brake-like system under unilateral contact and Coulomb friction
  
  • Nguyen Quoc Son
  • Oueslati Abdelbacet
  • Steindl Alois
  • Teufel Andreas
  • Troger Hans
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2008, 336 (1-2), pp.203-209. This article considers the frictional interface waves generated by the flutter instability of the sliding steady state for an elastic tube in frictional contact with a rigid and rotating shaft. According to the values of the contact pressure, the rotation velocity and the friction coefficient, several periodic dynamical responses can be found under the form of travelling surface waves. Examples of stick-slip, stick-slip-separation and stick-slip-separation-reverse-slip waves are reported here. Some discussions on the stability of these waves are also given. (10.1016/j.crme.2007.11.011)
  DOI : 10.1016/j.crme.2007.11.011
• A homogenization-based constitutive model for two-dimensional viscoplastic porous media
  
  • Danas Kostas
  • Idiart Martin I.
  • Ponte Castañeda Pedro
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2008, 336, pp.79-90. An approximate model based on the so-called "second-order" nonlinear homogenization method is proposed to estimate the effective behavior of viscoplastic porous materials exhibiting transversely isotropic symmetry. The model is constructed in such a way that it reproduces exactly the behavior of a "composite-cylinder assemblage" in the limit of in-plane hydrostatic loading, and therefore coincides with the hydrostatic limit of Gurson's criterion for plastic porous materials. As a consequence, the new model improves on earlier "second-order" homogenization estimates, which have been found to be overly stiff at sufficiently high triaxialities and nonlinearities. The proposed model is compared with exact results obtained for a special class of porous materials with sequentially laminated microstructures. The agreement is found to be excellent for the entire range of stress triaxialities, and all values of the porosity and nonlinearity considered. (10.1016/j.crme.2007.10.017)
  DOI : 10.1016/j.crme.2007.10.017