Dissertations / Theses on the topic 'Modélisation des déformations'
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Purwodihardjo, Ardie. "Modélisation des déformations différées lors du creusement des tunnels." Ecully, Ecole centrale de Lyon, 2004. http://bibli.ec-lyon.fr/exl-doc/apurwodi.pdf.
Full textSince the past 30 years, the research for estimating an accurate prediction of deformations induced by tunneling has been a major engineering challenge all around the world. The in situ measurements have shown that deformations of the soil on the vicinity of a tunnel show a strong evolution with time. Three essential phenomena, actually, can be related to this evolution : the evolution with time of the distance to the working face, the distance of the lining to the working face and the viscous effets occurring in the soil. The objective of this thesis is to propose a procedure for predicting the deformations induced by tunneling, by taking into account these three essential phenomena, particularly the third phenomenon. Therefore, in this study, a constitutive model for the time-dependent behaviour of cohesive soil has been developed within the framework of elastoplasticity-viscoplasicity and critical state soil mechanics. The consideration of viscoplastic characteristic sets the current model apart from the CJS model, and introduces an additional viscous mechanism. The evolution of the viscous yield surface is governed by a particular hardening called "viscous hardening" with a bounding surface. To describe this procedure and the capability of the model, a comparison between numerical calculations and monitoring the progressive closure of tunnel conducted in the TGV tunnel of Tartaiguille, is performed. The finite difference software, Fast Lagrangian Analysis of Continua (FLAC), has been used for the numerical simulation of the problems. The comparison results show that the observed deformations could have been reasonably predicted by using the proposed excavation model
Taverna, Joël. "Modélisation mécanique des déformations de la lithosphère." Grenoble 1, 1998. http://www.theses.fr/1998GRE10084.
Full textSaad, Patricia. "Modélisation et identification du comportement non linéaire des cales en caoutchouc." Ecully, Ecole centrale de Lyon, 2003. http://bibli.ec-lyon.fr/exl-doc/psaad.pdf.
Full textWe develop a numerical model to compute non linear rubber bush response. The objective is to take into account elasticity, damping, and non linear properties in a simple model dedicated to full vehicle modelling simulation. It is therefore important that the constitutive model a accurately capture theses aspects of the mechanical behaviour. To take into account these properties, Finite Element Codes use several complex constitutive laws. All these constituve equations can be integrated in finite element models and many algorithms are developed for this purpose. The main drawback of this procedure is its complexity. The number of dof is too high to be integrated in a vehicle study. Our work aims at giving a simplified approximation of the force as a function of the displacement and its derivatives, starting from a microscopic constitutive equation. Starting from a finite element model and a constutive law, we want to generate an equivalent rheological model, with a few dof. This model aims at predicting the frequency response of the bush, function of its geometry, of the load, of the parameters of the constitutive law. To do so, we approximate the displacement as a linear combination of admissible kinematic displacement fields, according to the Rayleigh-Ritz approximation. Hyperelastic models are used to fit on linear quasi static force deflection curves. Viscoelastic constitutive laws are also developped. In order to predict amplitude dependency observed when we measure steady state harmonic response, we use a Volterra development of the stress strain constitutive equation. To take into account preload effects, we linearize a viscohyperelastic model. The predictions of these models are compared to experimental data
Ghetreff, Taoufik. "Modélisation du comportement élasto-viscoplastique en grandes déformations." Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-229.pdf.
Full textSellier, Nicolas. "Modélisation expérimentale des interactions entre déformations salifères et sédimentation turbiditique : une nouvelle approche expérimentale appliquée aux déformations des corps salifères allochtones." Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10172/document.
Full textSalt-bearing passive margin with large clastic sediment supply are characterized by gravity-driven tectonics that deforms the sedimentary overburden and the underlying salt. These deformations are controlled along the continental rise by the differential loading generated by the deposition of turbidite fan (gravity spreading). Locally, along mature margin, extrusion of evaporites form allochthonous salt nappes (tens kilometres long) that are remobilized and deformed by the deposition of turbiditic lobes. Two end-members are recognized: the stepped counterregional structural style, which is dominated by subsidence of the sedimentary cover and distal salt extrusion. The roho structural style, which is dominated by lateral translation accommodated by several extensional structures.We designed a completely new kind of experimental apparatus for studying the interaction between sedimentation and salt tectonics along passive margin. Our device combines two approaches that are traditionally distinct: (1) the stratigraphic approach aiming to simulate sediment transport and deposition, and (2) the tectonic approach focusing on the deformation of the salt and its sedimentary cover. Thus, the tectono-stratigraphic basin built during this PhD work allows the modelling of turbiditic transport and deposition processes, as well as, salt-related deformations induced by differential loading of a mobile salt substratum at regional (gravity spreading) or local (allochthonous salt bodies remobilization)
Chardon, Dominique. "Les Déformations Continentales Archéennes : Exemples naturels et modélisation thermomécanique." Phd thesis, Université Rennes 1, 1996. http://tel.archives-ouvertes.fr/tel-00619433.
Full textLiu, Xiao Jing. "Modélisation des grandes déformations élasto-plastiques de coques axisymétriques." Compiègne, 1992. http://www.theses.fr/1992COMPD513.
Full textDumais, Simon. "Modélisation de la consolidation au dégel à grandes déformations." Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/37552.
Full textThis thesis presents the development of an engineering method for the modelling of large strain nonlinear thaw consolidation. The work presented herein follows existing thaw consolidation theories and models. The foundations of one-dimensional thaw consolidation theory are therefore used. First, a numerical model for large strain nonlinear thaw consolidation is formulated by combining the Gibson large strain consolidation theory to heat transfer equations. The two components are coupled in a modelling domain formulated in Lagrangian coordinates that adapts to the soil deformation. This results in the introduction of a second moving boundary at the soil surface to model thaw consolidation in addition to the moving boundary at the thaw front. The model uses nonlinear σʹv – e – kv relationships to define the properties of thawed soils. A case study of the Inuvik experimental pipeline with the numerical model is presented. The case study demonstrates the use of the model for a practical problem and it is used to validate the model. The modelling results are compared to the results obtained with the small strain linear thaw consolidation theory and with the field data. The results obtained with the large strain nonlinear model for thaw settlement, the rate of thaw settlement and the excess pore pressures compare favourably with the field data. Second, a conceptual model for thaw consolidation of thawed fine-grained soils is proposed. The model is used to define the characteristics of the nonlinear σʹv – e – kv relationships used as input for the numerical modelling of thaw consolidation. The concept of the residual stress is generalized to ice rich soils by specifying that it is the effective stress within the soil element rather than the effective stress of the bulk soil. Then, empirical relationships are formulated to determine the characteristics of the σʹv – e – kv relationships as a function of the initial thawed void ratio and soil index properties.
Zenasni, Mohammed. "Caractérisation expérimentale et modélisation du comportement du cuivre en grandes déformations : sensibilité à la vitesse." Metz, 1992. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1992/Zenasni.Mohammed.SMZ9234.pdf.
Full textThe subject of the thesis was to analyse the rate sensitivity of polycrystalline copper at large strains, order of 300 % in shear. This subject has not been so far explored and literature sources are extremely limited. On the other hand there is a great interest in including the rate effects in constitutive modelling. The torsional Hopkinson Bar (Kolsky apparatus) has been used to study the rate affects at high strain rates. At lower strain rates in shear than 300 s-1, a fast torsion machine was also employed. New computer programs developed in this purpose permitted for complete analyses of the shear stress vs. Shear strain curves at different strain rates. Tests with changes of strain rate have also been performed and the results studied within the framework of constituve modelling based on evolution of the mean dislocation densites. In general, application of the constitutive formalism based on evolution of microstructure and thermal activation (rate sensitivity of strain hardening and instantaneous rate sensibility) gave good results in modelling and comparison with experimental data
Carcan, Alain. "Modélisation des grandes déformations axisymétriques de membranes minces hyperélastiques incompressibles." Compiègne, 1985. http://www.theses.fr/1985COMPS134.
Full textAfane, Mostapha. "Etudes expérimentales et modélisation de la déformation plastique d'un fer, grandes déformations, sensibilité à la vitesse et histoire de chargement." Metz, 1997. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1997/Afane.Mostapha.SMZ9744.pdf.
Full textThis work describes the behavior of a cubical system metal centered : the iron 0. 02% C with the help many experimental results. The first part of this thesis is devoted to a bibliographical study whose which the sensitivity of the behavior of metals CC to the speed of deformation, to the temperature is put in obviousness, the indication of the possibility of the appearance of the mecanical twining for the great speeds of deformation, the existence for metals CC of them limit inferior elasticity and superior and then element of the theory of dislocation. The second part presents used experimental techniques and relationships of result deprivation. The third part is devoted to the representation of results and their analysis. Several observation experimental in this thesis : them limit elasticity that increases with the speed of deformation, differences of sensitivity to the speed according to the type of loading and the effect of the aging on the peaks of elasticity. Finally, the introduction of a model based on the activation thermal that fact introduce notions of the effective and internal stress governing the plastic flow whose evolution is linked to energy of activation
Youssef, Hiba. "Modélisation viscoplastique pour les déformations et les évolutions des textures dans les polycristaux : Homogénéisation par une loi intermédiaire." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13016.
Full textKeryvin, Vincent. "Contribution à la modélisation de l'endommagement localisé." Poitiers, 1999. http://www.theses.fr/1999POIT2370.
Full textDubois-Coutte, Jocelyne. "Modélisation de céramiques électrostrictives pour transducteurs électroacoustiques." Lille 1, 1998. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1998/50376-1998-271.pdf.
Full textDans un premier temps, ce travail incorpore de nouveaux outils de calcul dans le code atila. Des elements finis specifiques permettant la modelisation numerique de materiaux electrostrictifs sont valides experimentalement et/ou analytiquement en statique et en dynamique sur un barreau et/ou sur une sphere. Dans un second temps, ces developpements numeriques sont utilises pour concevoir, realiser et tester un transducteur prototype a 20 khz a base de ceramiques electrostrictives. Plusieurs resultats ont ete obtenus : l'obtention d'un coefficient du couplage equivalent a celui d'un transducteur piezoelectrique pour un meme volume de materiau actif et un meme encombrement ; une amplitude vibratoire normalisee en tension plus importante pour le transducteur electrostrictif a l'antiresonance
Alvo, Sébastien. "Etude, modélisation et mesure des forces d'adhésion à l'échelle microscopique." Paris 6, 2012. http://www.theses.fr/2012PA066563.
Full textThe behavior of microsized objects is governed by surface effects. Reliable interaction models between micro-objects and robots end-effectors are required for micromanipulation. Numerous parameters are involved in adhesion forces modeling. The influence of each of these parameters must be determined in order to control forces and especially the one which is required to split to contacting objects: the pull-off force. Moreover, at the microscale, measurements of interaction forces during a manipulation task are complex and are only available in few cases. The general approach of this work can be divided into three main steps. After a presentation of the micromanipulation context, models and measurement tools of the literature are depicted in the first step (chapter 1). Two modeling approaches are highlighted; where strengths and weaknesses of models are focused in chapter 2 in order to develop a new adhesion forces model during the second step (chapter 3). This model highlights coupling between local deformations and adhesion forces and exposes major differences between microscale and nanoscale. Finally, the objective of the third step is the correlation of the proposed model with experiments. The analysis of experimental results is presented in the chapter 4. The results show the difficulties encountered for modeling interactions between real micro-objects and highlights a scale effect on electrostatic forces
Ciuciu, Ioana. "Proposition pour la prise en compte des déformations métiers dans un système de CAO." Reims, 2009. http://theses.univ-reims.fr/exl-doc/GED00001088.pdf.
Full textThe CAD domain today reflects the actual technological and scientific evolution. We are currently witnessing a universalization of the design techniques, which are often based on the same algorithms, in domains ranging from industry to medicine. This multidisciplinary aspect induces different views on the design. The design is no longer done by engineers but by a very heterogeneous public, and results in the use of different interaction techniques. In order to fit to this diversity, the CAD systems should assist the user with adapted modelling tools. An approach in this direction is to integrate trade-based knowledge with the deformations. The designer has thus he possibility to concentrate on his/her trade rather than on the geometric model, leaving to the system the task of transmitting the trade parameters to the model. The present study has been realised within the DIJA project with the purpose of creating a trade-oriented surface deformation modeller, not only by using the underlying geometric model, as it was realised until present, but by taking into account a surface triangulation as fine as needed. This study also demonstrates the refinement of the trade-based parameters into geometric parameters and the user-system interaction at different levels of the system’s architecture, depending on the user’s competencies
Muriel, Gerbault. "Modélisation numérique de la naissance des déformations localisées : exemple du flambage lithosphérique." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 1999. http://tel.archives-ouvertes.fr/tel-00522321.
Full textZontsika, Nöel Alain. "Modélisation multiéchelle du couplage élasto-plasticité-endommagement par décohésion en grandes déformations." Thesis, Paris 13, 2014. http://www.theses.fr/2014PA132024/document.
Full textSince decades, the study of mechanical and physical properties of UFG and NC microstructures has considerably increased as well as processing techniques. The growing interest in these materials comes from new behaviors encountered with wide range of applications perspectives in many scientific and technologic engineering fields, with high added value and important economic issues such as microelectronics, telecommunications, aeronautics, energy and army. In mechanics, the growing interest resides in both the possibility of processing microstructures with high mechanical strength and high ductility. However, these last microstructures have shown a very low strain hardening capacity although they were observed to have a high mechanical strength. New deformation mechanisms are suspected to induce these behaviors namely grain size deformation mechanisms which cause Hall-Petch strain profile inversion and/or early damage. Nowadays, there are many techniques to process UFG and NC microstructures with both high mechanical strength and improved strain hardening capacities. Similarly, simulation numerical tools have helped to understand some phenomenon still not accessible via experiments. Boring in mind this last aspect, a micromechanics modeling was proposed in this work to characterize microstructure influence on yield stress and damage and to study the crystalline texture evolution
Inal, A. Kaan. "Modélisation numérique de l'aluminium à grandes déformations plastiques, applications au calcul parallèle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ40592.pdf.
Full textInal, A. Kaan. "Modélisation numérique de l'aluminium à grandes déformations plastiques : applications au calcul parallèle." Mémoire, Université de Sherbrooke, 1998. http://savoirs.usherbrooke.ca/handle/11143/1046.
Full textBaghdadi, Abdelhakim. "Modélisation en grandes déformations des solides et des sols : applications aux fondations." Compiègne, 1993. http://www.theses.fr/1993COMPD649.
Full textKhamlichi, Jamal. "Modélisation de déformations d'images tridimensionnelles : application aux structures de données de visages." La Rochelle, 1995. http://www.theses.fr/1995LAROS002.
Full textGerbault, Muriel. "Modélisation numérique de la naissance des déformations localisées : exemple du flambage lithosphérique." Montpellier 2, 1999. http://www.theses.fr/1999MON20025.
Full textPaul, Anne. "Modélisation numérique des déformations d'un édifice volcanique : applications au Mont St Helens." Grenoble 1, 1986. http://www.theses.fr/1986GRE10006.
Full textRabahallah, Meziane. "Modélisation de l'anisotropie plastique et application à la mise en forme des tôles métalliques." Thesis, Metz, 2007. http://www.theses.fr/2007METZ044S/document.
Full textThis research work, realized in two laboratories (LPMM of ENSAM of Metz and LPMTM of Paris 13 university) proposed to study the plastic anisotropy of sheet metals during forming operations. The applications in mind concern the prediction, through the forming process numerical simulation, of the initial plastic anisotropy and its influence on the global behaviour of the sheet. An anisotropy that manifest, during forming operation, by the apparition of undulations on the sheet edge. To do this, a class of strain rate potential has been introduced. Potential written in the frame of so called dual approach (less commonly used), where the introduce variable is the plastic strain rate, contrary to the classical approach (commonly used), where the criterion is defined with stress tensor. In addition, the material work-hardening has been considered by introducing internal variables. A large study has been devoted to the identification of the different criteria introduced, basing on the experimental data, as well as those of material texture measure. The materials under study are some steel grades and aluminium alloys. Different identification strategies have been investigated, in order to insure of the good determination of the behaviour model parameters. To allow the exploitation of the different criteria in the frame of the forming process simulation, a robust and efficient computer implementation has been performed in a finite element code. A solver routine following implicit time integration scheme has been developed in order to obtain a good accuracy. The modelling has been applied to the prediction of anisotropic coefficient. This study highlighted the capability of each criterion to reproduce the strong plastic anisotropies. Then, the application of this modelling to the study of deep drawing corns has been realized and allowed to show the effects of the criterion on the number of the formed corns as well as there pronunciation degree. A correlation between the Lankford coefficient and the deep drawing corns has been established
Guines, Dominique. "La lubrification des liaisons compliantes : modélisation et algorithmes." Poitiers, 1994. http://www.theses.fr/1994POIT2306.
Full textThomas, Jean-Philippe. "Etude expérimentale et modélisation de l'évolution microstructurale du superalliage 718 en déformation à chaud." Saint-Etienne, EMSE, 2005. http://www.theses.fr/2005EMSE0002.
Full textThis study aims at the identification of the recrystallization mechanisms of superalloy 718 that are observed on microstructures characterized by EBSD, after a high temperature deformation in torsion or uniaxial compression. Then a model of microstructural evolution is designed. Experimental investigations reveal that the mechanisms of boundary generation and disorientation determine the recrystallization behavior of superalloy 718. A study of the evolution of subboundary disorientation histograms shows that the localized disorientation of subgrains is the leading nucleation mechanism of the first new grains. Twin boundary generation and disorientation are involved in the nucleation of the further generations of grains. The model results from the combination of formulations dealing, firstly with boundary generation and disorientation, which lead to nucleation, and secondly with the treatment of grains interactions, be it with themselves or with d phase (Ni3Nb) precipitates
Leszczynski, Aleksander. "Modélisation de l'arthrodèse thoraco-lombaire avec fixation pelvienne dans les déformations du rachis." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD041.
Full textDegenerative scoliosis and sagittal imbalance are common problems in the older population. In order to improve the quality of life, some patients are recommended to undergo surgical correction. Surgical correction of the sagittal balance can lead to various complications, including rod fractures, which play a central role in the long term. Patient follow-up studies have shown that a rupture of the osteosynthesis material is observed in about 20% of patients. The main focus of the curent work was the development of a complete finite element model (FEM) of the healthy spine. The geometry of the FEM was based on a CT-scan of a healthy 47-year-old volunteer. Mechanical properties were taken from a wide literature review and implemented. In order to ensure the biofidelity, the spinal FEM was widely validated in terms of range of motion (ROM) and modal analysis against multiple experimental studies from the literature. For the study of osteosynthesis material, four instrumented FEMs of the lumbar spine with different configurations were proposed. For the first time, a validation was performed on instrumented flexible spine FEMs against ROM as well as strains in the main rods. In addition, other mechanical parameters such as intradiscale pressure, forces in the screw heads and the distribution of Von Mises stresses in the main rods were calculated to evaluate the studied instrumented configurations. Outcome of the present study of the four instrumented lumbar FEMs in four loading modes (extension flexion, lateral inflection and torsion) indicated that the maximum Von Mises stress (located in the main rods) is correlated with the area of rod fractures reported in patient follow up studies. However, the bi-lateral double rod configuration with interbody cages produced the higher Von Mises stress reduction on spinal fixators which represents a minimal risk of rod failure. A complementary study was also carried out to investigate the FEM of an instrumented spine from T10 to the pelvis. The results showed that an extension of the instrumentation thoracic part, the numerically obtained values were more critical than during an instrumentation of the lumbar part alone, especially in terms of maximum stresses calculated in the principal rods. The developed spinal FEM can be an effective and efficient tool to evaluate other surgical instrumentation techniques using the finite element method
Mekkaoui, Smaine. "Modélisation de l'incertain sur les essais triaxiaux en grandes déformations sur sols remaniés." Châtenay-Malabry, Ecole centrale de Paris, 2002. http://www.theses.fr/2002ECAP0954.
Full textOmar, Mirvat. "Déformations différées du béton : étude expérimentale et modélisation numérique de l'interaction fluage-endommagement." Nantes, 2004. http://www.theses.fr/2004NANT2117.
Full textThe aim of this research is to investigate numerical and experimental studies of coupling between creep and crack growth in concrete. The numerical study underlines the different approaches that can be envisioned in order to incorporate damage into the time dependent creep functions: In the Maxwell model, the effective stress approach was used. In the Kelvin model, material damage acts on the time independent part of the creep functional. The numerical models are calibrated so that they fit the experimental data. Some computer simulations have been carried out. Results of various loading histories with different controlling parameters confirm the influence of the damage behaviour on creep or relaxation of concrete. Besides, another type of modeling based on a discrete approach was handled in this study: the Zip model, which has been modified in order to consider the viscoelasticity of concrete. Results show that the length of the Fracture Process Zone decreases when increasing viscoelasticity. In addition to the numerical models, a large experimental program should also give many indications about the interaction between creep and crack and allow to conclude simplified rules predicting the capacity of a structure to resist to crack growth taking into consideration the time dependent behavior of concrete. This experimental program is intended to analyse the influence of flexural creep on the capacity of concrete beams, it is also intended to study the variation of the material behaviour after creep on the size effect law. The load level effects on creep strain are also discussed. Basic creep experiments show that for high load levels there is a coupled effect between creep and damage as tertiary creep is observed. Acoustic emission analysis was also performed during creep loading, the aim is to correlate the evolution of the cumulative AE events and energy vs. The deflection of the beam
Zeghib, Nasser-Eddine. "Etude expérimentale et modélisation de la déformation plastique tenant compte du vieillissement dynamique : cas des aciers doux." Metz, 1990. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1990/Zeghib.Nasser_Eddine.SMZ9014.pdf.
Full textSchreiber, Dimitri. "Modélisations géométriques 3D et champs de déformations dans les Alpes du Sud." Nice, 2010. http://www.theses.fr/2010NICE4115.
Full textWe present the results of an integrated geological study which combine geological mapping and structural analysis, 3D geometrical modelling and geophysical modelling in order to characterize the superposed strain patterns of the Southwestern Alps at various scales. We propose 3D geometrical models of some remarkable sedimentary basins (Cretaceous South-East basin, Paleogene foreland basins of the Arc de Nice, Miocene basin of Roquebune-Cap-Martin) and of the Moho topography in the Southwestern Alps. These results support the following tectonic history : The tectonic and sedimentary evolution of the Southern subalpine chains during late Cretaceous times is ascribed to a submeridian crustal shortening coeval with eht Pyrenean-Provence de formation phase and the initiation of the subduction of the Alpine Tethys. The Nummulitic transgression which took place in the Southern subalpine chain followed an emersion period generalized to the whole European platform at the end of the late Creataceous. The return of the Overlapping Tertiary sedimentation is controlled by the northeastward underthrusting of the foreland below the alpine collision wedge. The resulting crustal shortening lead to buckle folding and flexuring of the alpine foreland? The related synclines are filled by the syn-orogenic sedimentary sequence of the late Eocène trilogy. This deformation (D1), active until Chattian ages, lead to the appearance of N140° striking folds, in the present-day, to the exhumation of the Argentera-Mercantour crystalline massif. This tectonic feature lead to the down-sliding of the Mesozoic and Cenozoic sedimentary cover toward the south and the deformation of the Pliocene mollasic basin of the Var valley. At crustal scale, the finite strain partitioning observed in the Southern subalpine chains, from Eocene time to present-day is controlled at depth by the indentation of the European lithosphere by the Ivrea body. This mantle slice localizes and transfers the deformation. This later controls the crustal shortening of the external zones and the exhumation of the internal zones
La, Borderie Christian. "Phénomènes unilatéraux dans un matériau endommageable : Modélisation et application à l'analyse de structures en béton." Paris 6, 1991. http://www.theses.fr/1991PA066185.
Full textChateau, Xavier. "Sur quelques problèmes liés à la modélisation mécanique de l'emboutissage." Palaiseau, Ecole polytechnique, 1992. http://www.theses.fr/1992EPXX0015.
Full textTrombini, Marion. "Couplage endommagement-grandes déformations dans une modélisation multi-échelle pour composites particulaires fortement chargés." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2015. http://www.theses.fr/2015ESMA0002/document.
Full textThis study is devoted to multi-scale modeling of highly-filled particulate composites.This method, the “Morphological Approach” (M.A.), is based on a geometrical and kinematicalschematization which allows the access to both local fields and homogenized response. In order toevaluate the predictive capacities of the M.A. considering a linear elastic behavior for the constituentsand evolution of damage, analysis is performed regarding the ability of the M.A. to accountfor particle size and interaction effects on debonding chronology. For that purpose, simple periodic,random monomodal and bimodal microstructures are considered. The results are consistent withliterature data : debonding of large particles occurs before the one of smaller particles and thehigher the particle volume fraction, the sooner the debonding. Finally, the objective is to operatethe coupling of two non linearities which were separately studied in previous versions of the M.A. :debonding between particles and matrix, and finite strains. The whole analytical background of theapproach is reconsidered in order to define the localization-homogenization problem. The nucleationcriterion is extended to the finite strains context. The final problem, strongly non linear, is numericallysolved through a Newton-Raphson algorithm. The different solving steps (jacobian matrix,coding with Python®) are developed. Progressive evaluations (sound and damage materials) allowthe validation of numerical implementation. Then, size and interaction effects are reproduced infinite strains
Gréalou, Lionel. "Modélisation biomécanique d'interventions chirurgicales sur la cage thoracique pour le traitement des déformations scoliotiques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ57408.pdf.
Full textNie, Zhigang. "Utilisation des déformations pour la modélisation des solides de forme libre en synthèse d'images." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1991. http://tel.archives-ouvertes.fr/tel-00817748.
Full textPham, Van Bang Damien. "Comportement instantané et différé des sables des petites aux moyennes déformations : expérimentation et modélisation." Lyon, INSA, 2004. http://theses.insa-lyon.fr/publication/2004ISAL0026/these.pdf.
Full textA new triaxial apparatus was developed at ENTPE especially for investigating time and strain rate effects on the behaviour of dry Hostun sand. For this purpose, the test device allows stress and strain controlled tests at different strain rates. Piezoelectric sensors are placed in the platens and used for wave’s propagation tests in compressive and in shear mode. The axial and radial strain measurements are obtained locally by the means of non contact transducers. The behaviour of sand can be studied from very small (some 10-6 m/m) up to large strain domain (some 10-2 m/m). The experimental procedure investigates first the behaviour of sand in the small strain domain which is quasi elastic and non viscous (instantaneous). The determination of the vertical Young modulus is obtained by the use of two methods. One is static by applying cycles at very small strain amplitude (of some 10-5 m/m). The other is dynamic and based on inverse analysis of waves received and emitted by the piezoelectric elements. A good agreement is observed between dynamic and quasi static methods results. A model which is hypoelastic type is presented and used for simulations. The testing program includes also creeps, relaxations tests and tests with stepwise changes in the strain rates to highlight the viscous (or delayed) behaviour of sand. Tests with stepwise changes in the strain rate reveal a specific aspect for sand. This is particularly described by the viscous evanescent model developed in the laboratory. Simulations for creeps, relaxations and stepwise changes in the rate are proposed
Aelaai, Mohammad-Réza. "Contribution à l'etude de la modélisation des grandes déformations élasto-plastiques : problèmes de remaillage." Compiègne, 1986. http://www.theses.fr/1986COMPI239.
Full textNingre, Corado. "Modélisation du comportement élastoplastique cyclique multiaxial par une approche multisurface dans l'espace des déformations." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI053.
Full textThis work deals with the theoretical, numerical and experimental study of the elastoplastic mechanical behavior of metallic materials in complex multiaxial cyclic loadings. The elastoplastic behavior is described by a multisurface model, within the finite strain theory. This model is written in the five-dimensional Ilyushin strain space. The resulting model is capable of describing the multiaxial behavior of metallic materials, in complex cyclic loadings, in particular non-proportional, taking into account finite strain, time-independent irreversibility, cumulative second order effects (Poynting-Swift effect) and cyclic hardening. The model has been implemented in a commercial finite element calculation code, in order to produce an operational tool for calculating structures such as mechanical equipment and internal components of hydroelectric power plants (turbines, alternators, etc.). The proposed model was validated by comparison with combined tensile-torsion biaxial test results obtained on stainless steel. This model has been completed by an energy and thermodynamic analysis that allows the implementation of a relevant energy approach for the monitoring of fatigue damage. As part of this work, this approach was illustrated by the proposal of a fatigue criterion, validated by the comparison of its predictions with those of other classical fatigue criteria proposed in the literature
Gaaloul, Hichem. "Contribution a la modélisation de l'élastoplasticité anisotrope en grandes déformations : application aux tôles d'emboutissage." Ecully, Ecole centrale de Lyon, 1993. http://www.theses.fr/1993ECDL0027.
Full textFelix, Sunil. "Modélisation des déformations et contraintes dans une pièce de bois en cours de séchage." Bordeaux 1, 1990. http://www.theses.fr/1990BOR10508.
Full textAbdulhameed, Hemin. "Réponse viscoélastique-viscoplastique en grandes déformations du polyéthylène : observations expérimentales, modélisation constitutive et simulation." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10055/document.
Full textThis PhD dissertation deals with the large-strain mechanical response of polyethylene. In a first part, experimental observations are reported on the time-dependent mechanical response of polyethylene materials containing a wide range of crystal fractions. In a second part, a large-strain viscoelastic-viscoplastic constitutive model is developed to capture the progressive transition from thermoplastic-like to elastomeric-like mechanical response of polyethylene materials, as the crystal content changes. In order to identify the model parameters, an analytical deterministic scheme and a practical, “engineering-like”, numerical tool, based on a genetic algorithm are developed. In a third part, the proposed constitutive model is implemented into a finite element code and used to predict the response of multi-layered polyethylene specimens with different crystal fractions. Comparisons between the simulations and the experimental data (in terms of mechanical response and necking evolution) point out the model predictive capabilities
Biakeu, Guy. "Modélisation multicorps : application au crash des structures." Ecully, Ecole centrale de Lyon, 2000. http://www.theses.fr/2000ECDL0023.
Full textIndustrial norms in terms of security and comfort of the passengers cars, aiplanes or boats are becoming more and more draconian. The constructors are now obliged to succeed severe tests like the resistance of their products to crashes or their stability. Moreover, these aspects happenned to be excelent arguments for the marketing departements as consumers prefer solid cars or trains to beautifull ones. On another hand, economic reasons bring industrials to reduce the number of real tests on the full structure and to increase the use of numerical simulation during the conception of vehicules. In this thesis we develop a technique based on multibody modelling of beams. It takes large displacements and large rotations in charge. We called it the Large Curvature Description (LCD). In the plane, the shape of the beam are interpolated with arcs of circle. In the space, we use Euler angles to describe the orientation of the sections and we introduce elementary angles to keep the same linear evolution of the orientation as in the plane. Only bending and torsion deformations are studied but we can extend the formulation to traction and shear. Plastic regions are modelled as nonlinear hinges. The behaviour of these hinges is represented by a mathematical expression in which the collapse appears as a negative exponential The hinges are located with an interpolation of the bending moments and the torsion moment built as a norm on the structure. Constraints systems are solved with the Lagrange multipliers technique and we use an explicit scheme to solve the equations of motion. We compare our results to those of simulation under explicits codes as ABAQUS/Explicit or to techniques developped by authors in the literature
Taboada, Alfredo. "Modélisation numérique en tectonique : applications dans les domaines ductile et cassant." Montpellier 2, 1992. http://www.theses.fr/1992MON20022.
Full textArrieta, escobar Juan Sebastian. "Modélisation du Comportement Thermomécanique des Polymères à mémoire de Forme." Thesis, Paris, ENSAM, 2014. http://www.theses.fr/2014ENAM0031/document.
Full textA chemically crosslinked amorphous acrylate network has been prepared in the laboratory. Its mechanical properties were characterized by quasi-static and cyclic uniaxial tensile tests, while varying the temperature. The shape memory property of the polymer was recognized by the application of specific thermomechanical cycles in uniaxial tension (free-length and constrained-length recovery). During the experimental study, the thermomechanical cycle parameters were varied in order to study their influence on the shape memory behavior. Two additional studies were included to improve the potential applications of shape memory polymers. The first study targeted the use of the material shape memory property for subsequent shape memory cycles. The second study aimed at improving the material shape memory properties during fixed length heating (constrained-length recovery) by adding fillers .In order to improve the shape memory polymers application design, a large strain model, combining the material viscoleasticity and its time-temperature superposition property, was chosen to predict the shape memory behavior of the material. The model features, existing in the material behavior libraries of the finite element code Abaqus, allowed simulating numerically the experimental thermomechanical shape memory cycles. Results of the simulations showed good agreements when compared with the experimental results, reproducing the shape memory cycles influence to loading parameters. A parameter sensitivity analysis revealed the shape memory property dependence on the time-temperature superposition
Fayet, Thierry. "Contribution à la modélisation des matériaux élastoplastiques écrouissables : application aux sols." Châtenay-Malabry, Ecole centrale de Paris, 1999. http://www.theses.fr/1999ECAP0691.
Full textBassigny, Véronique. "Déformation du polyétheréthercétone amorphe et semi-cristallin : modélisation et influence des antécédents thermomécaniques." Lille 1, 1991. http://www.theses.fr/1991LIL10089.
Full textKhedimi, Farid. "Modélisation micromécanique des élastomères chargés." Phd thesis, Aix-Marseille 1, 2011. http://tel.archives-ouvertes.fr/tel-00628202.
Full textCelle, Pierre. "Couplages fluide / milieu poreux en grandes déformations pour la modélisation des procédés d'élaboration par infusion." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2006. http://tel.archives-ouvertes.fr/tel-00741260.
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