Дисертації з теми "Caoutchouc – Endommagement, Mécanique de l' (milieux continus) – Modèles mathématiques"
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Glanowski, Thomas. "Compréhension et modélisation des mécanismes élémentaires d’endommagement en fatigue d’élastomères renforcés au noir de carbone." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2019. http://www.theses.fr/2019ENTA0009.
Повний текст джерелаThe fatigue properties of carbon black filled elastomers are strongly related to the inclusions’ population, induced by complex recipes and the successive stages of the manufacturing process (mixing, injection and curing). The improvement of these properties involves at first an ability to describe the statistical features of these inclusions’ population in terms of nature, size, geometry, orientation and spatial distribution. Then, a detailed understanding of the damage mechanisms is required in order to define the mechanical criticality of inclusions according to their characteristics under cyclic loading. This study presents at first the tools developed, based on a detailed analysis of X-ray micro-tomography data. The obtained results on the inclusion’s populations and the damage induced allow highlighting the potential of these tools and their current limits for the studied materials. Atypical inclusions, unknown in the litterature, has been discovered. The cavitation mechanism appears to be the most critical regarding fatigue because it leads to micro-cracks that propagate in the matrix. A comparison of the criticality of the inclusions’ parameters regarding a cavitation criterion is carried out with a parametric study using finite elements simulations. Finally, thermographic measurements at the inclusions’s scale show the additional investiguations needed for a better understanding of the damage mechanisms at this scale
Warneboldt, Iona. "Multiaxial fatigue design of elastomeric parts using Equivalent Fatigue Loads." Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2022. http://www.theses.fr/2022ENTA0002.
Повний текст джерелаThis thesis introduces an Equivalent Fatigue Load (EFL) approach for the multiaxial fatigue design of elastomeric parts. As direct Finite Element Analysis (FEA) calculations of automotive in-service loads (Road Load Data (RLD)) are too expensive, the objective is to derive simplified load blocks as a realistic input for numerical damage calculations. Three streps are applied for this method: the localization method, the material damage function and the EFL determination process. Various fatigue tests have been conducted (415 samples) to study the fatigue behavior of this complex type of relaxing and non-relaxing multiaxial loading on natural rubber specimens. Lifetime and crack features are analyzed to eventually introduce an appropriate critical planebased fatigue measure and to establish a novel mean strain effect model. This criterion is generalized throughout an original critical plane search method. To estimate the local mechanical response (localization method), this thesis identifies an axes-coupling method that is fitted for the nonlinear nature of elastomeric structures. It is based on the multiplicative decomposition of the deformation gradient tensors. These two steps are then implemented in the framework of the EFLdetermination process. For this, a global optimization method is added to determine the simplified load blocks, causing locally the same fatigue behavior in the given structure. The computational costs of this optimization are reduced by only considering a subset of the most damaged material points for EFLdetermination. Finally, the method has been challenged on a specimen to outline its capabilities and to validate the approach
Touchard, Fabienne. "Spécificités du comportement mécanique de composites stratifiés à fibres longues et à matrice thermoplastique." Poitiers, 1994. http://www.theses.fr/1994POIT2338.
Повний текст джерелаMartin, Boris. "Formulation intégrale de l'approche DNRL et réflexions sur l'endommagement." Vandoeuvre-les-Nancy, INPL, 2003. http://www.theses.fr/2003INPL054N.
Повний текст джерелаWelemane, Hélène. "Une modélisation des matériaux microfissurés - Application aux roches et aux bétons." Phd thesis, Lille 1, 2002. http://oatao.univ-toulouse.fr/6638/1/Welemane_6638.pdf.
Повний текст джерелаHelfer, Thomas. "Etude de l'impact de la fissuration des combustibles nucléaires oxyde sur le comportement normal et incidentel des crayons combustible." Ecully, Ecole centrale de Lyon, 2006. http://bibli.ec-lyon.fr/exl-doc/thelfer.pdf.
Повний текст джерелаThis thesis aims to model the cracking of pressurised water reactor fuel pellets and its consequences on the mechanical behaviour of the fuel rod. Fuel cracking has two main consequences. It relieves the stress in the pellet, upon which the majority of the mechanical and physico-chemical phenomena are dependent. It also leads to pellet fragmentation. Taking fuel cracking into account is therefore necessary to adequately predict the mechanical loading of the cladding during the course of an irradiation. The local approach to fracture was chosen to describe fuel pellet cracking. Practical considerations brought us to favour a quasi-static description of fuel cracking by means of a local damage models. These models describe the appearance of cracks by a local loss of rigidity of the material. Such a description leads to numerical difficulties, such as mesh dependency of the results and abrupt changes in the equilibrium state of the mechanical structure during unstable crack propagations. A particular attention was paid to these difficulties because they condition the use of such models in engineering studies. This work was performed within the framework of the ALCYONE fuel performance package developed at CEA/DEC/SESC which relies on the PLEIADES software platform. ALCYONE provides users with various approaches for modelling nuclear fuel behaviour, which differ in terms ofthe type geometry considered for the fuel rod. A specific model was developed and implemented to describe fuel cracking for each of these approaches. The 2D axi-symmetric fuel rod model is the most innovative and was particularly studied. We show that it is able to assess, thanks to an appropriate description of fuel cracking, the main geometrical changes of the fuel rod occurring under normal and off-normal operating conditions
Guillemer-Neel, Clervie. "Comportement mécanique et endommagement de la fonte à graphite sphéroïdal." Compiègne, 1999. http://www.theses.fr/1999COMP1184.
Повний текст джерелаSupartono, Franciscus Xaverius. "Contribution à la modélisation de l'endommagement anisotrope du béton : Texte imprimé." Ecully, Ecole centrale de Lyon, 1985. http://www.theses.fr/1985ECDL0015.
Повний текст джерелаAndo, Kohei. "Modélisation théorique de l'endommagement des matériaux composites et application de l'effet de l'endommagement à la rupture et à l'optimisation." Compiègne, 1987. http://www.theses.fr/1987COMPD072.
Повний текст джерелаBatisse, Rémi. "Contribution à la modélisation de la rupture ductile des aciers : étude quantitative de l'état inclusionnaire d'un acier ferritique faiblement allié au Mn-Ni-Mo et de son influence sur l'amorçage et la propagation de la déchirure ductile." Compiègne, 1988. http://www.theses.fr/1988COMPI279.
Повний текст джерелаHurez, Anita. "Modélisation du comportement de stratifiés avec prise en compte de l'évolution de l'endommagement à l'aide d'un élément de plaque incluant les effets de cisaillement transversal." Compiègne, 1993. http://www.theses.fr/1993COMPD564.
Повний текст джерелаBourgeois, Frédéric. "Élaboration des modèles rhéologiques des argilites et bétons partiellement saturés avec prise en compte de la microfissuration." Lille 1, 2002. http://www.theses.fr/2002LIL10056.
Повний текст джерелаGentot, Laëtitia. "Adoucissement par fatigue des milieux élastomères : caractérisation, modélisation et simulation numérique." Lille 1, 2003. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2003/50376-2003-207-208.pdf.
Повний текст джерелаRivallant, Samuel. "Modélisation à l'impact de pales d'hélicoptères." Toulouse, ENSAE, 2003. http://www.theses.fr/2003ESAE0018.
Повний текст джерелаAbdullah, Elie. "Développement d'un élément fini pour la modélisation du délaminage dans les structures composites." Toulouse, ENSAE, 2005. http://www.theses.fr/2005ESAE0033.
Повний текст джерелаRoy, Gilles. "Vers une modélisation approfondie de l'endommagement ductile dynamique : investigation expérimentale d'une nuance de tantale et développements théoriques." Poitiers, 2003. http://www.theses.fr/2003POIT2271.
Повний текст джерелаThe aim of the thesis work is the proposition of a method for the experimental and theoretical study of shock-induced damage in ductile metals, with view to a physically-based constitutive modelling. A high purity grade of tantalum is selected to support the analysis. The influence of micro-inertia on dynamic ductile damage evolution is essential. It introduces some characteristic lengths related to the microstructure. To take inertia into account, a multi-scale modelling describing some evolution of this microstructure is needed. Consequently, the analysis first relies on the experimental characterization of the stages of the damage process, that is for tantalum micro-void nucleation, growth and coalescence. The results guide the micromechanical analysis which leads to the suggestion of a model framework based on a two-scale micro-macro transition fitted with the dynamic context
Zitoune, Redouane. "Analyse des conditions d'usinage lors du perçage de structures composites fibres longues en carbone-époxy." Toulouse 3, 2004. http://www.theses.fr/2004TOU30182.
Повний текст джерелаThe drilling of composite structures long fibres in carbon/epoxy is accompanied by damages which are indexed according to their place of appearance. We distinguish three zones: at the entry of the hole - which corresponds to the separation of the top ply of the laminate, at the wall of the hole - with wrenching of fibres and the resin degradation, and at the exit of the hole - with the separation of the last ply. The zones of the wall and hole exit are the place of the major defects which harm the lifetime of bolted or riveted assemblies. Within the framework of this work we are interested in the analysis of the wall and exit hole defects. To analysis the wall defect, a simplified study is proposed. It consists in a numerical and experimental study of the orthogonal cutting of unidirectional laminates. The angle (q) between the fibres and the cutting speed direction (Vc) is respectively 0ʿ, +45ʿ, 90ʿ and -45ʿ. For the analysis of the defect at the hole exit, an experimental and numerical study on two types of materials in carbon/epoxy long fibres is carried out
Feng, Zhi-Qiang. "Contribution à la modélisation des problèmes non linéaires : contact, plasticité et endommagement." Compiègne, 1991. http://www.theses.fr/1991COMPD443.
Повний текст джерелаSakji, Mohamed Seddik. "Modélisation probabiliste et validation expérimentale du transfert thermique et du comportement thermomécanique avec endommagement d'une plaque multicouche carton-plâtre-carton soumise au feu." Marne-la-Vallée, 2006. http://www.theses.fr/2006MARN0286.
Повний текст джерелаGeffroy, Anne-Gaëlle. "Modélisation numérique de la rupture de structures navales sous l'effet d'explosion au contact." Lorient, 2010. http://www.theses.fr/2010LORIS209.
Повний текст джерелаIn the context of military vulnerability of ships and submarines, this work, supported by a DCNS-LIMATB CIFRE, deals with the numerical prediction of the response of ship structures submitted to contact explosion. The ship structure constitutive material at stake is ferritic-pearlitic, mild steel. In order to study the coupling effects of stress triaxiality, strain, strain rate and temperature, an important experimental campaign was carried out, including laboratory mechanical tests as well as air blast tests. The microstructural observations of post-mortem samples and plates revealed the co-existence of two different mechanisms of ductile damage: cavity growth and micro-cracking. In agreement with the experimental results and the micrographic observations, an advanced elastic-thermo/viscoplastic model was built and a more complete, original formalism is proposed through a multi-surface and multi-mechanism model, describing notably the delaying effects of strain rate and temperature on the damage kinetics and the consequences of both damage mechanisms, namely isotropic (cavity growth) and anisotropic (microcracking). Models were finally implemented as user materials in the engineering finite element computation code ABAQUS. Several configurations of air blast tests were simulated using the card CONWEP of ABAQUS, devoted to reproduce the fluid/structure interaction during the process of explosion and which limits were shown. The numerical results are encouraging and some improvements are suggested
Homsi, Moaz. "Simulation de la découpe des métaux par un modèle de déchirure ductile, à l'aide de techniques de remaillage." Compiègne, 1995. http://www.theses.fr/1995COMPD850.
Повний текст джерелаZhou, Jianjun. "Contribution à la modélisation de l'endommagement anisotrope et de la variation de la perméabilité des roches fragiles." Lille 1, 2006. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2006/50376-2006-Zhou.pdf.
Повний текст джерелаZaïri, Fahmi. "Contribution à l'étude de la déformation et de l'endommagement des polymères vitreux homogènes et à renforts caoutchoutiques." Lille 1, 2004. http://www.theses.fr/2004LIL10127.
Повний текст джерелаPotet, Pierre. "Contribution de la vibrothermographie à la détection et à la caractérisation de l'endommagement dans les matériaux composites." Compiègne, 1988. http://www.theses.fr/1988COMPD110.
Повний текст джерелаA modelisation of the heat transfer phenomenas occurring during vibrothermographic experiments was carried out. The theoretical model can be used in the case of a thin orthotropic plate. It permits the determination of the heat source field from a measured temperature field. The experimental study was made with impacted damaged specimens. The results obtained from vibrothermographic experiments were compared with those obtained from standard NDT tests, such as ultrasonics, radiography and tomodensitometry. The results clearly show the high potential of this technique for the detection and characterisation of damage in composite materials
Huez, Julitte. "Influence de l'hydrogène sur les mécanismes d'endommagement du titane alpha et d'un alliage de titane biphasé alpha/bêta." Compiègne, 1996. http://www.theses.fr/1996COMPD950.
Повний текст джерелаLuquiau, Denis. "Caractérisation du comportement et de l'endommagement de l'alliage de titane Ti-10V-2Fe-3AI en fatigue." Compiègne, 1996. http://www.theses.fr/1996COMPD923.
Повний текст джерелаTaraf, Modar. "Endommagement par fatigue de contact d'une roue ferroviaire : étude numérique par éléments finis." Thesis, Metz, 2008. http://www.theses.fr/2008METZ021S/document.
Повний текст джерелаThis study by finites elements proposes to estimate the Rolling Contact Fatigue (RCF) strength of a railway wheel. The first part of the thesis presents a critical analysis of the approaches of the literature relatives to the various aspects of the problem of RCF. The second part relates to the two-dimensional modeling of a railway wheel, consist a defect circular, and subjected to a moving hertzian contact pressure .The damage is quantified by a Fatigue Parameter (FP) based on the density of energy and the concept of critical plan. The lifetime is calculated using a law consist of the parameters of low-cycle fatigue. It is shown that the technique of the submodeling is an effective tool to reduce the computing time CPU. The third chapter is a parametric study about the influence over the lifetime, of the loading level, the defect depth, the nature and the size of the defects. The results show that the critical plan of crack initiation is parallel to the contact surface when mode I dominate; it deviates when mode II is dominating. The fourth chapter relates to the influence of the loadings with variable amplitudes and that of friction. We show the beneficial effect of an overload over the lifetime to crack initiation. The harmful incidence of the coefficient of friction over the lifetime is highlighted in the case of a wheel with and without defect. Finally, the last part of this work approaches the effects of inertia in the case of the RCF. The lifetime is over-estimated in the static case and decreases in dynamics with the rolling speed and the loading level
Lee, Jae Rock. "Étude et modélisation de l'endommagement des stratifiés carbone-époxy (± 45°)2s et (0°/90°)2s." Compiègne, 1985. http://www.theses.fr/1985COMPI207.
Повний текст джерелаBenameur, Fouad. "Modélisation thermo-mécanique de la coulée sous pression en fonderie." Compiègne, 1996. http://www.theses.fr/1996COMPD885.
Повний текст джерелаBezzina, Smail. "Modélisation théorique et numérique du procédé de découpage des tôles." Compiègne, 1996. http://www.theses.fr/1996COMPD874.
Повний текст джерелаZhang, Yu. "Etude expérimentale et modélisation du comportement mécanique d’une roche tendre." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10052/document.
Повний текст джерелаThe short term and long term mechanical behaviors of cataclastic sandstone are investigated in this dissertation. The studied material is cored from the fault zone in the dam foundation of a hydropower station in southwestern China. The emphasis is put on the long-term behavior of studied material. For this, conventional compression tests, multi-stage triaxial creep tests as well as the permeability measurements are performed. The mechanical behavior of studied rock is derived based on the experimental investigation. The mechanical responses of studied material are not only functions of the material properties, but are also related to applied stress. Based on the experimental investigation, a unified creep model is proposed to describe the instantaneous and time-dependent behavior of cataclastic sandstone. Main features observed in experiments are taken into account, in particular irreversible deformations, pressure dependency, volumetric transition between compaction and dilatancy and creep. The performance of the model is examined by comparing numerical simulations with test data in representative load paths. Finally, the model is applied to analyze the long term stability of a foundation of hydropower station
Mohamad-Hussein, Assef. "Modélisation du comportement mécanique des géomatériaux semi-fragiles soumis à des sollicitations mécaniques et à la dégradation chimique." Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-Mohamad_Hussein.pdf.
Повний текст джерелаBenmedakhene, Salim. "Étude phénoménologique du comportement à l'impact des matériaux composites." Compiègne, 1996. http://www.theses.fr/1996COMPD918.
Повний текст джерелаChen, Da. "Modélisation du comportement hydromécanique d'un mortier sous compression et dessiccation." Lille 1, 2005. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2005/50376-2005-276.pdf.
Повний текст джерелаBelayachi, Naïma. "Analyse du comportement des polymères chocs avec la prise en compte de l'endommagement par cavitation." Lille 1, 2006. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/a8de7da2-1bb0-4eac-b442-26c071600c07.
Повний текст джерелаChen, Liang. "Contribution à la modélisation du comportement hydromécanique des géomatériaux semi-fragiles." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10144/document.
Повний текст джерелаThis work is devoted to the constitutive modelling of hydromechanical behaviours of semi-brittle geomaterials. In the first part, the attention is mainly paid on the hydromechanical behaviours of initially isotropic materials, especially on the influence of desiccation process on the mechanical responses. An elastoplastic damage model is proposed in unsaturated condition, a generalized effective stress concept is used for poroplastic coupling. Damage by microcracks is coupled with plastic deformation. In the second part, two coupled elastoplastic damage models are proposed for the description of strongly anisotropic sedimentary materials. In the first model, in order to describe the inherent anisotropy of the material, a scalar anisotropy parameter is introduced using the concept of fabric tensor. In purpose of studying the coupling phenomenon between the inherent and induced anisotropies during the loading process, a model based on the discrete approach is constructed in the following. In the framework of plastic discrete approach, the macroscopic plastic deformation and material degradation are considered as the result of frictional sliding along weakness planes distributed randomly in the material. In the last chapter, the proposed discrete model is extended to poroelastoplastic modelling. Based on a series of numerical simulation, an analysis of hydromechanical behaviour of anisotropic materials is realised
Traore, Nafissatou. "Modélisation numérique de la propagation des failles décrochantes dans la lithosphère." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066203/document.
Повний текст джерелаNumerical modelling of strike-slip faults propagation is essential to understand the long-term mechanical behavior of the lithosphere. Firstly, we aim to reproduce the interseismic deformation of a preexisting fault. The modelling of this interseismic regime enables us to determine what rheology and loading, both mechanically and geologically justifiable, are required to obtain a surface deformation that matches the geodetic measurements. When the lateral displacement is due to the long-term plates motion, a structural heterogeneity has to be imposed by the mean of a weak viscous zone beneath the locked fault. Secondly, we study fault propagation by using damage mechanics. This approach allows the prediction of damage evolution, without previously knowing the propagation path, and makes the link with the Griffith's theory. We improve this approach with the introduction of a residual tangential stress on the fault that is similar to fault planes friction, and we use mixed resolution methods, which represents a novelty in damage mechanics. These developments make possible the description of fault evolution for simple cases, and open the way towards the use of new growth and propagation fault models
Viant, Thibaut. "Caractérisation et modélisation du comportement dynamique des propergols solides et vulnérabilité des systèmes propulsés." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI045/document.
Повний текст джерелаThe design and qualification tests of rocket motors require knowledge of the mechanical behavior of the materialsused to manufacture them. In this aim, a large range of strain rates have to be considered, this range integratemany solid propellant service situations. Knowledge of their behaviour should make it possible to predict the risksassociated with unexpected stress on propelled vehicles (difficult transport conditions, falls). The usual methodologyuses both numerical and experimental approaches. This methology is based on several uniaxial tesile tests, DMA andtensile tests under pressure to identify the parameters of the constitutive law (HRVM). However, it was indicatedthat the usual method did not allow satisfactory numerical predictions to be performed when the strain rate isgreater than 50 s−1. This PhD work proposes new experimental characterization techniques to complement existingresults for a range of strain rates of about 100 s−1. Original tests ensuring dynamic and homogeneous loadingshave been developed. A dynamic tensile test has been designed to characterize composites elastomers highly filled(CaCO3 and aluminum). A heterogeneous dynamic shear test of edge-on impact has been also adapted, this testmakes it possible to assess the state of damage in the material during and after the impact. The material parametersquantified with new mechanical tests have been integrated into the existing parameter library. The firsts numericalsimulations using these new parameters have made it possible to extend the practice of numerical model used byAriane Group
Hérisson, Benjamin. "Endommagement discret et continu : application aux materiaux quasi-fragiles." Thesis, Lorient, 2018. http://www.theses.fr/2018LORIS483/document.
Повний текст джерелаIn this thesis, some fundamental considerations of the modeling of failure are addressed for discrete damage systems. The goal is to establish, starting with simple structural problems, a bridge between the Discrete Damage Mechanics (DDM) and that of the non-local Continuum Damage Mechanics (CDM). It is currently accepted that DDM systems must be considered in a non-local framework to obtain consistent results, especially during numerical modeling of softening phenomena based on damage laws. We support this non- locality on the scale of the microstructure of the material. Using a continualisation procedure and with the use of the Padé approximant, we were able to obtain the analytic expression of the non-local continuous approximation offering an accurate simulation of the discrete problem for the whole damage process. We study the systems of the discrete axial chain under traction, the discrete bending beam and the microstructured membrane under uniform pressure. The discrete system is first solved, then the discrete equations are continualised to obtain a non-local continuum model. For each of these problems, careful attention is paid to the boundary conditions of the continual problem, the importance of which is illustrated throughout this manuscript
Tran, Tan Huy. "Contribution à l’établissement d’un modèle rhéologique thermo-hydro-chimio mécanique de l’argilite du Callovo-Oxfordien." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10179/document.
Повний текст джерелаThe study aims to evaluate the radioactive waste storage structures in argillite Callovo- Oxfordien : The first part presents the model SC2D (Swelling Creep Diagenesis Damage) used to simulate the behaviour of argilite, this model is based on special hydro-mechanical characteristics of the argillite Callovo-Oxfordien; The second part shows the applications of SC2D model to describe anisotropic damaged areas around the excavated structures. These EDZ zones are determined when the damage coefficients are unitary and the discontinuities activate when damage coefficient reaches unity, damaged coefficients are calculated from an extension of Mazars by considering the extension deformation in the directions of diagenesi; the final part discussess the delayed effects around the structures after excavation; they are represented by the deformation velocity vectors whose amplitudes are governed by the level of damage and the deviatoric stress. The comparison between in situ convergence measurements and modeled results validates the deformation velocity vectors
Gruescu, Ion Cosmin. "Approche par changement d'échelle de l'endommagement des matériaux anisotropes : application aux composites à matrice fragile." Lille 1, 2004. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2004/50376-2004-229-230.pdf.
Повний текст джерелаDans le cadre des techniques d'homogénéisation basées sur l'utilisation des tenseurs d'Eshelby, on propose ensuite une approche tridimensionnelle des milieux orthotropes contenant des fissures ouvertes modélisées par des cylindres infinis. Les résultats obtenus (tenseur d'Eshelby, tenseur de Hill) sont entièrement nouveaux, notamment dans le cas de fissures arbitrairement orientées par rapport aux axes d'orthotropie. Ils mettent clairement en évidence l'interaction entre l'orientation de la microfissuration et l'orthotropie initiale du matériau. Le dernier volet de l'étude est dédié à la modélisation tridimensionnelle de l'endommagement dans les composites à symétrie orthotrope de révolution, affaiblis par des fissures de forme circulaire ("penny-shaped cracks"). En raison de la difficulté particulière à aborder ce problème 3D dans le cadre des méthodes d'homogénéisation, on propose une approche mixte originale combinant les théorèmes de représentation et des résultats issus de la micromécanique. Les bonnes capacités prédictives du modèle macroscopique d'endommagement ainsi élaboré, de même que les comparaisons avec des données expérimentales, permettent de valider la démarche développée
Kacem, Ahmed. "Étude de la capacité limite de déformation dans les procédés de mise en forme par déformation locale." Lorient, 2013. http://www.theses.fr/2013LORIS288.
Повний текст джерелаThis thesis deals with the experimental and numerical investigations of the limits of the flanging process arising from material failure. The methodology developed in this study was applied particularly to the stretch flanging process of a hole in sheet metal called the hole-flanging process. The materials studied are made of A1050-H14 and A6061-O aluminium alloys. Mechanical characterizations have been performed through uniaxial tensile and shear tests. An elasticplastic finite element models based on isotropic and anisotropic yield criteria were developed. These models were enhanced by the integration of the damage in simulation. Experiments were conducted to verify the reliability of the developed finite element models. First, the effect of the clearance thickness ratio on the hole-flanging process was studied. A methodology was made to distinguish two conditions of the process: hole-flanging with and without ironing. Then, the effect of material anisotropy assumptions on the predictive accuracy of finite element simulations of the hole-flanging process was quantified. The study was then focused on the determination of the limits of hole-flanging process arising from material failure. For that purpose, a fracture criterion was calibrated and used in simulations to predict the damage of the flange. Finally, the damage occurrence in flanged edge was characterized by using the coupled approach of Gurson-Tvergaard-Needleman
Hu, Dawei. "Contribution à l’étude du comportement mécanique et hydromécanique d’une roche endommagée." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10150/document.
Повний текст джерелаThis thesis presents the laboratory and numerical investigations on anisotropic mechanical, poromechanical and fluid transport behavior of sandstone. After the X-ray and SEM tests, the samples were stressed under triaxial loading to study the initial and stress-induced mechanical behavior. The evolution of anisotropic Biot’s coefficients and axial permeability are also investigated and related to mechanical behavior. A plastic damage model is presented based on discrete approach. The proposed model is applied to simulate the mechanical behavior of dry sandstone under different loading conditions, the evolution and distribution of damage variable and plastic hardening variable are also discussed. Furthermore, the proposed model is applied to simulate the previous experimental results (including mechanical behavior, Biot's coefficients and permeability) of saturated sandstones. The comparisons between the numerical result and test data show a good performance of the present model. Finally, an anisotropic poroplastic damage model is developed to describe the poromechanical behavior of saturated sandstone. The comparisons between numerical simulation and experimental data is given for the triaxial compression tests under drained and undrained condition, the tests of strain response to pore pressure increment is also simulated, a good accordance is obtained
Scida, Daniel. "Étude et modélisation du comportement mécanique de matériaux composites à renforts tisses hybrides et non hybrides." Compiègne, 1998. http://www.theses.fr/1998COMP1168.
Повний текст джерелаZhu, Qizhi. "Applications des approches d'homogénéisation à la modélisation tridimensionnelle de l'endommagement des matériaux quasi fragiles : formulations, validations et implémentations numériques." Lille 1, 2006. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2006/50376_2006_41.pdf.
Повний текст джерелаNehme, Samer. "Contribution à l'approche numérique multi-échelles pour la modélisation du comportement mécanique de matériaux composites à renfort interlock." Compiègne, 2011. http://www.theses.fr/2011COMP1952.
Повний текст джерела2. 5D interlocks are particular reinforcements of aeronautic composite materials that are believed to have a high structural potential. This kind of reinforcement entails to consider the composite as a structure because interlocks are built by crossing the warp tows with the weft tows in the three directions. To evaluate the mechanical behavior, one may obtain numerically the anisotropic elastic engineering constant from a finite elements model. This technique of virtual testing consists to model the composite at it’s the meso-scale to obtain a macro-scale response with a stress-displacement analysis. We thus propose a new meshing methodology to build an elementary volume made of tetrahedral for the isotropic matrix and of mapped hexahedral for the transversely isotropic yarns. In order to achieve the finite element discretization, a geometrical model is developed from measurements taken from photomicrographs of an interlock composite. The industrial sofware package « Ansys Academic Associate » is used to solve the problem with contact element, local orientation of the anisotropy in yarns and computation of nine macroscopic orthotropic engineering constants. The numerical results are compared to experimental data and an analytical model. The finite element model shows a good agreement with our previous work. Beyond satisfying results for the elastic behaviour, the delamination is correctly described using a cohesive approach focusing on the concepts of linear elastic fracture stresses, associated with Mode I and mode II
Lai, Dawei. "Contribution à la modélisation de la rupture des plaques stratifiées entaillées sous un chargement monotone ou cyclique comprenant une sollicitation de compression." Compiègne, 1988. http://www.theses.fr/1988COMPD150.
Повний текст джерелаBen, Hatira Fafa. "Modélisation de l'élastoplasticité endommageable en transformations finies." Compiègne, 1992. http://www.theses.fr/1992COMPD531.
Повний текст джерелаMeraghni, Fodil. "Identification expérimentale des mécanismes d'endommagement contribuant à la modélisation micromécanique du comportement élastique-endommageable des composites à fibres discontinues orientées aléatoirement (C. F. D. O. A)." Compiègne, 1994. http://www.theses.fr/1994COMPD697.
Повний текст джерелаBouchart, Vanessa. "Étude expérimentale et modélisation micromécanique du comportement et de l'endommagement des élastomères renforcés." Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-Bouchart.pdf.
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