Publications

2001

• Non-destructive evaluation of a limit of acceptable damage for leather products
  
  • Luong Minh-Phong
  , 2001, pp.358-367.
• Modelling the Electromagnetic Forces Distribution in a Three Dimensional G.M.A.W. Weld Pool
  
  • Roger F.
  • Coiffier J. C.
  • Dang Van K.
  , 2001. No abstract provided
• Strain localization in two-phase materials and polycrystals: Quantitative experimental investigations and modeling attempts
  
  • Bornert Michel
  • Doumalin Pascal
  • Crépin Jérôme
  • Soppa Ewa
  , 2001.
• Avoiding the bloat with stochastic grammar-guided genetic programming
  
  • Ratle Alain
  • Sebag Michèle
  , 2002, pp.255-266. The application of Genetic Programming to the discovery of empirical laws is often impaired by the huge size of the search space, and consequently by the computer resources needed. In many cases, the extreme demand for memory and CPU is due to the massive growth of non-coding segments, the introns. The paper presents a new program evolution framework which combines distribution-based evolution in the PBIL spirit, with grammar-based genetic programming; the information is stored as a probability distribution on the grammar rules, rather than in a population. Experiments on a real-world like problem show that this approach gives a practical solution to the problem of introns growth. (10.1007/3-540-46033-0_21)
  DOI : 10.1007/3-540-46033-0_21
• Grammar-guided genetic programming and dimensional consistency: application to non-parametric identification in mechanics
  
  • Ratle Alain
  • Sebag Michèle
  Applied Soft Computing, Elsevier, 2001, 1 (1), pp.105-118. Although genetic programming has often successfully been applied to non-parametric modeling, it is frequently impaired by the huge size of the search space explored. Domain knowledge is a powerful way to trim out the size of the space, by restricting the search to a priori relevant models. A most natural domain knowledge in scientific modeling is known as dimensional analysis, stipulating that the models must be consistent with regards to the variable measurement units. In this paper, it is shown that dimensional analysis can automatically be expressed as a context free grammar. Dimensionally-aware GP is thus achieved by employing the dimensional grammar within the grammar-guided GP framework first investigated by Gruau [On using syntactic constraints with genetic programming, in: P. Angeline, K.E. Kinnear Jr. (Eds.), Advances in Genetic Programming II, MIT Press, Cambridge, MA, 1996, pp. 377–394.]. However, grammar-guided genetic programming encounters severe difficulties when it involves a complex grammar, which might explain why this approach has not been widely used so far. The drawback is blamed on the initialization step, which hardly constructs a sufficiently diversified initial population, thus hindering the success of evolution. This limitation is addressed by a new CFG compliant initialization procedure. The approach is validated on two problems related to the identification of mechanical properties of materials. (10.1016/S1568-4946(01)00009-6)
  DOI : 10.1016/S1568-4946(01)00009-6
• An example of stick-slip waves
  
  • Moirot Franck
  • Nguyen Quoc-Son
  , 2001, pp.109-116. An analytical solution representing a family of stick–slip waves is obtained in a simple example modelling the dynamic behaviour of an elastic cylindrical tube in contact with Coulomb's friction with a rigid and rotating cylinder. This family of waves, representing the non-trivial periodic responses of a continuous system of one space variable, is not classical in the literature. (10.1007/978-94-017-1154-8_12)
  DOI : 10.1007/978-94-017-1154-8_12
• Séparation et reconstruction des ondes dans les barres élastiques et viscoélastiques à partir de mesures redondantes
  
  • Othman Ramzi
  • Bussac Marie-Noëlle
  • Collet Pierre
  • Gary Gérard
  Comptes Rendus. Mécanique, Académie des sciences (Paris), 2001, 329 (5), pp.369 - 376. La durée du chargement habituellement utilisée avec le système des barres de Hopkinson (ou SHPB pour Split Hopkinson Pressure Bar) est limitée par la nécessité de séparer les ondes se propageant dans des sens opposés. En utilisant le principe du maximum de vraisemblance, et à partir de N mesures de déformation et P mesures de vitesse matérielle (N+P⩾2), nous construisons une nouvelle méthode de séparation des ondes dans les barres. Cette méthode permet de calculer, sans limitation de durée, les contraintes, les déformations, les déplacements et les vitesses matérielles en tout point de la barre. Elle tient compte des effets dispersifs aussi bien dans les barres élastiques que dans les barres viscoélastiques. Elle est illustrée sur une barre libre pour laquelle le déplacement mesuré est 30 fois supérieur à celui qui serait atteint par la méthode classique. (10.1016/S1620-7742(01)01343-5)
  DOI : 10.1016/S1620-7742(01)01343-5
• A Salt-cavern abandonment test
  
  • Bérest Pierre
  • Bergues Jean
  • Brouard Benoît
  • Durup Gerard
  • Guerber Benoît
  International Journal of Rock Mechanics and Mining Sciences, Pergamon and Elsevier, 2001, 38 (3), pp.357-368. Thousands of caverns have been leached out from deep salt formations. They are used for saturated brine production and/or hydrocarbons storage. They will be abandoned some day: the access well will be plugged with cement, isolating a large bubble of saturated brine. The later evolution of such a bubble raises serious concerns for environmental protection; salt creep and brine thermal expansion can lead to brine pressure build-up and rock-mass fracture, then brine seepage can lead to pollution of overlying water-bearing strata. Taking into account salt formation permeability leads to less pessimistic scenarios. An 18-month test has been performed on a deep brine-filled cavern. The objective was to measure the brine equilibrium pressure reached when the cavern is closed. Such an equilibrium is reached when salt mass creep, which leads to cavern shrinkage, balances brine permeation through the cavern wall. This objective was met by imposing different pressure levels and observing whether the pressure increased (or decreased) with respect to time. Data misinterpretation (i.e., a well leak instead of a cavern-proper leak) was precluded by a special monitoring system. The observed equilibrium pressure was significantly smaller than geostatic pressure, alleviating any fracture risk for a sealed and abandoned cavern in this salt formation. (10.1016/S1365-1609(01)00004-1)
  DOI : 10.1016/S1365-1609(01)00004-1
• Identification of elastoviscoplastic materials: a discussion about uniqueness
  
  • Constantinescu Andrei
  , 2001.
• Modelling rate-dependent effects in heterogeneous materials
  
  • Masson Renaud
  • Zaoui André
  , 2001.
• Influence of the test frequency and environment on mode II fatigue crack growth in a maraging steel
  
  • Doquet Véronique
  , 2001.
• Wear modelling of contact plan/plan between graphite and titanium alloy
  
  • Serre Ingrid
  • Bonnet Marc
  • Celati N.
  • Duval Rachel-Marie Pradeilles
  , 2001, pp.287-293.
• Nondestructive evaluation of rock material instability
  
  • Luong M. P.
  , 2001, pp.463-466. No abstract provided
• Increasing the maximum strain measured with elastic and viscoelastic bars
  
  • Ohtman Ramzi
  • Bussac Marie-Noëlle
  • Collet Pierre
  • Gary Gérard
  , 2001, pp.49-56. A new method has been developed for separating dispersive waves in elastic and viscoelastic rods from multi-point strain and velocity measurements. Knowing then the basic waves, the stress, the strain, the displacement and the particle velocity can be calculated at any point of the bar. The method is based on the assumption of one dimensional and single mode dispersive wave propagation and it takes account of the wave dispersion. It is shown that the method is stable with respect to noise, so that 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 longer limited by the length of the bars. The method is illustrated here by applying it successfully to the analysis of a real test of aluminum honeycomb. It can also be applied to other kinds of one-dimensional and single-mode dispersive waves such as flexural waves in beams and acoustic waves in wave-guides.
• Infrared observation of the mechanical performance of tennis strings
  
  • Luong M. P.
  , 2001, pp.624-635. No abstract provided
• Approche par contrôle optimal des structures élastoviscoplastiques sous chargement cyclique
  
  • Peigney Michaël
  • Stolz Claude
  Comptes Rendus de l'Academie des Sciences Serie II, Gauthier-Villars, 2001, 329, pp.643-648. On utilise l'approche par contrôle optimal pour étudier le comportement de structures élastoplastiques sous chargement cyclique. L'état asymptotique est ainsi obtenu comme solution d'un problème approché cohérent avec une discrétisation spatiale. Dans ce cadre, on montre que les seuls points stationnaires de la fonctionnelle à minimiser sont les minima globaux. (10.1016/S1620-7742(01)01381-2)
  DOI : 10.1016/S1620-7742(01)01381-2
• Comportement mécanique non linéaire et homogénéisation
  
  • Bornert Michel
  , 2001.
• Fatigue Analysis of Welded Structures during Random Loadings
  
  • Zarka Joseph
  • Karaouni Habib
  , 2001.
• Homogénéisation des milieux aléatoires : bornes et estimations
  
  • Bornert Michel
  • Bretheau Thierry
  • Gilormini Pierre
  , 2001, pp.133-222.
• Stability of a quasi-static evolution of a visco-elastic, visco-plastic or elastic-plastic solid
  
  • Abed-Meraim Farid
  • Nguyen Quoc Son
  , 2001, pp.1-14. The problem of stability of a quasi-static evolution of a solid is discussed in the framework of standard plasticity and visco-plasticity. General results concerning the criterion of second variation of energy are presented. Two different approaches are considered to discuss this problem for visco-elastic, visco-plastic or elastic-plastic solids. The first approach is based upon the linearization method and gives the asymptotic stability of the evolution of a visco-elastic solid when the associated dissipation potential is quadratic and positive-definite. The second approach introduces a direct analysis of the evolution in a nonsmooth but convex framework of plasticity and visco-plasticity. (10.1007/978-1-4613-0275-9_1)
  DOI : 10.1007/978-1-4613-0275-9_1
• Life-time prediction of aluminum automotive components under thermo-mechanical cyclic loadings
  
  • Verger Laetitia
  • Charkaluk Eric
  • Constantinescu Andrei
  , 2001.
• Identification of constitutive parameters in engineering problems
  
  • Constantinescu Andrei
  • Lecampion Brice
  • Verger Laetitia
  • Tardieu Nicolas
  , 2001.
• Affaissement en surface lors du creusement d'un souterrain
  
  • Bérest Pierre
  • Ghoreychi Mehdi
  • Habib Pierre
  Revue française de Géotechnique, edp sciences, 2001, 92, pp.41-47. L’affaissement à long terme de la surface du sol au-dessus d’un tunnel est comparé à l’affaissement instantané au moment du creusement dans le cadre de l’élasticité linéaire. Les résultats numériques montrent, sur des exemples vraisemblables, que si des déplacements importants sont décelés en surface, il s’agit très probablement de déformations irréversibles. (10.1051/geotech/2000092041)
  DOI : 10.1051/geotech/2000092041
• sur les mécanismes de la plasticité et de l'endommagement
  
  • Berveiller M.
  • Bretheau T.
  • Fougères R.
  • Gautier E.
  • Maire E.
  , 2001, pp.203-249.
• Etude thermodynamique de l'évolution sous chargement dynamique de structures délaminées
  
  • Pradeilles-Duval Rachel Marie
  Comptes rendus de l’Académie des sciences. Série IIb, Mécanique, Elsevier, 2001, 329, pp.535-540. On considère un assemblage de plaques modélisant une structure stratifiée se délaminant. La propagation du délaminage est caractérisée par la transformation d'une plaque en deux autres. On examine dans le cadre du formalisme hamiltonien l'influence d'un chargement dynamique sur une telle structure, d'un point de vue thermodynamique. L'étude du taux de restitution associé à la propagation de la fissure, considérée comme une source de chaleur localisée sur le front de délaminage, est discutée. (10.1016/S1620-7742(01)01364-2)
  DOI : 10.1016/S1620-7742(01)01364-2