Tesi sul tema "Arme numérique"
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Merabet, Omar. "Modélisation des structures planes en béton arme sous chargements monotone et cyclique : construction et validation d'un modèle numérique". Lyon, INSA, 1990. http://www.theses.fr/1990ISAL0005.
Testo completoPapy, Alexandre. "Etude numérique de la balistique intérieure des armes de petit calibre". Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211017.
Testo completoCe document synthétise un travail de quatre années relatif à l'étude des phénomènes dynamiques rencontrés dans une arme de petit calibre. Jusqu'à présent, des efforts ont été réalisés pour simuler des armes de gros calibre, avec plus ou moins de succès. L'adaptation directe de ces méthodes au petit calibre est, la plupart du temps, décevante car peu précise. De plus, le coût des essais en arme de petit calibre, relativement faible par rapport à des essais en armes de calibre plus important, a contribué au désintérêt des études dans ce domaine. Encore aujourd'hui, des fabriquants d'armes de renommée internationale ne disposent pas de modèles pour le petit calibre. Celui-ci a été, et reste encore aujourd'hui, le parent pauvre des simulations numériques en balistique intérieure.
A l'heure actuelle, de nombreuses recherches sont entreprises dans le cadre des canons électriques ou électromagnétiques. Ces armes, qui représentent peut-être le futur de la balistique, ne sont encore qu'à un stade fort éloigné d'une utilisation effective et opérationnelle. La situation est donc assez paradoxale :les armes de petit calibre sont les plus utilisées (dans le cadre d'une utilisation militaire, sportive ou à des fins de tests) mais il n'existe, à proprement parler, que peu de modèles mathématiques permettant une simulation précise et rigoureuse. Dans ce contexte, ce travail va démontrer que des modèles de balistique intérieure peuvent être utilisés avec succès pour la simulation de tirs en armes de petit calibre.
Une des originalités de ce travail consiste en l'utilisation d'un logiciel de CFD (Computational Fluid Dynamics} comme squelette d'un simulateur de la balistique intérieure, et à son application sur des armes de petit calibre. L'approche employée permet de dissocier les aspects "mécanique des fluides" et traitement de l'écoulement, des aspects purement balistiques. Nous nous attacherons donc à évaluer la capacité d'un code CFD à fonctionner dans l'environnement particulier de la simulation du "coup de canon".
Plan du travail
Cette thèse peut être subdivisée en quatre différentes parties. La première partie, plutôt générale, vise à situer le problème dans son contexte. Elle débute par une introduction rapide à la balistique, et s'attarde sur les buts de la balistique intérieure en mettant l'accent sur les particularités des armes de petit calibre, le cas échéant.
La simulation sur ordinateur est un aspect important du problème qui doit nécessairement être mis en rapport avec des résultats réels. C'est pourquoi la chaîne de mesure utilisée classiquement en balistique, ainsi que les dispositifs expérimentaux employés pour obtenir des résultats de validation, sont brièvement présentés dans la deuxième partie.
La troisième partie est axée sur les modèles. Nous présentons les principaux types de modèles que l'on peut retrouver en balistique intérieure. Les modèles à paramètres globaux et à paramètres locaux sont développés et nous formulons quelques remarques générales au sujet de l'état de l'art dans ce domaine, avant de nous interroger sur la problématique du choix d'un logiciel CFD adapté à l'utilisation visée.
Nous présentons alors le logiciel choisi, et détaillons les modèles qu'il utilise pour tenir compte des particularités de la balistique intérieure. Le mouvement du projectile dans l'arme, la combustion et le traitement du problème diphasique sont notamment passés en revue et développés.
Mobidic (Mobidic est l'acronyme de :MOdélisation Balistique Intérieure DIphasique Canon) est un logiciel français que nous avons obtenu vers la fin de cette étude. Ce logiciel est reconnu pour sa capacité à modéliser précisément les tirs en arme de moyen et gros calibre. Son fonctionnement et les modèles qu'il utilise sont exposés et comparés à notre implémentation.
La quatrième et dernière partie n'est certainement pas la moins importante. Elle présente les résultats issus des tirs que nous avons réalisés et les différentes étapes de validation qui ont été menées à bien, depuis les tests de base jusqu'à la validation totale dans deux armes de petit calibre.
Enfin, les conclusions, remarques et directions futures clôturent ce travail.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
Rousseau, Jessica. "Modélisation numérique du comportement dynamique de structures sous impact sévère avec un couplage éléments discrets / éléments finis". Phd thesis, Grenoble 1, 2009. http://www.theses.fr/2009GRE10219.
Testo completoThat study focuses on concrete structures submitted to impact loading and is aimed at predicting local damage in the vicinity of an impact zone as well as the global response of the structure. The Discrete Element Method (DEM) seems particularly well suited in this context for modeling fractures. An identification process of DEM material parameters from macroscopic data (Young's modulus, compressive and tensile strength, fracture energy, etc. ) will first be presented for the purpose of enhancing reproducibility and reliability of the simulation results with DE samples of various sizes. Then, a particular interaction, between concrete and steel elements, was developped for the simulation of reinforced concrete. The discrete elements method was validated on quasi-static and dynamic tests carried out on small samples of concrete and reinforced concrete. Finally, discret elements were used to simulate impacts on reinforced concrete slabs in order to confront the results with experimental tests. The modeling of a large structure by means of DEM may lead to prohibitive computation times. A refined discretization becomes required in the vicinity of the impact, while the structure may be modeled using a coarse FE mesh further from the impact area, where the material behaves elastically. A coupled discrete-finite element approach is thus proposed: the impact zone is modeled by means of DE and elastic FE are used on the rest of the structure. An existing method for 3D finite elements was extended to shells. This new method was then validated on many quasi-static and dynamic tests. The proposed approach is then applied to an impact on a concrete structure in order to validate the coupled method and compare computation times
Rousseau, Jessica. "Modélisation numérique du comportement dynamique de structures sous impact sévère avec un couplage éléments discrets / éléments finis". Phd thesis, Grenoble 1, 2009. http://tel.archives-ouvertes.fr/tel-00411870.
Testo completoL'application de la méthode des éléments discrets sur des structures de grandes dimensions est limitée par le nombre d'éléments discrets nécessaires. Pour garder la qualité de prédiction locale et rendre cette méthode adaptée à l'échelle d'une structure, celle-ci est couplée à la méthode des éléments finis dans les parties qui ne sont pas soumises à d'importantes discontinuités. Cette approche couplée permet des gains de temps importants, tant pour la modélisation que la pour la simulation.
Une partie importante de cette thèse concerne le développement et la validation du modèle éléments discrets de béton armé. Ce travail propose une optimisation du processus d'identification des paramètres locaux du modèle discret afin de le rendre plus prédictif en ce qui concerne le béton. Ensuite, une liaison particulière, entre éléments discrets d'acier et de béton, a été conçue pour la simulation du béton armé. Enfin, elle a été utilisée pour la simulation d'impacts sur des dalles en béton armé afin de confronter les résultats à des essais expérimentaux.
La deuxième partie du travail de thèse traite de la méthode de couplage entre éléments discrets et éléments finis. Une méthode existante pour les éléments finis volumiques a été étendue aux éléments finis de type coque. Enfin, la méthode de couplage a été utilisée pour simuler un impact sur une structure de type enceinte de confinement.
Chabaud, Laurent. "L'arme numérique : essai sur la dématérialisation des infractions pénales". Electronic Thesis or Diss., Université de Montpellier (2022-....), 2023. http://www.theses.fr/2023UMOND043.
Testo completoThe development of the Internet, and of digital technology in general, has facilitated the commission of a large number of offences, and has made its entry into most branches of criminal law. However, there is still one branch of criminal law where digital technology has not made its entry: offences against the physical integrity of the person. Doesn't this logical rejection raise questions? The development of objects connected to the Internet means that such attacks are becoming a reality. The possibility of such attacks must therefore be incorporated into the Penal Code. The first part of this paper proposes to explore this possibility by bringing together the notions of weapon and digital to create the notion of digital weapon. Although these notions may seem antinomic, they are in fact relatively close. Their integration into the penal code shows that they obey the same mechanism: sanctioning the use of a particular tool - a weapon or a digital device - to commit an offence. We therefore propose a paradigm shift in the analysis of the weapon to bring these notions closer together. This re-theorization of the weapon around its function, which we call the mode of perpetration, enables us to take better account of the dematerialization of offences. The second part sets out to extend the regime of the "mode of perpetration" weapon to include the digital weapon, thereby strengthening the economic efficiency of the law in the fight against cybercrime. In particular, this allows us to take a global approach to cybercrime, favoring proactive rather than merely reactive analysis
Orengo, José Ramon. "Modélisation numérique des structures en béton armé". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1990. http://tel.archives-ouvertes.fr/tel-00529365.
Testo completoAndami, Ovono Armel. "Équations de diffusion paramétrée par la portée des interactions à longue distance". Poitiers, 2009. http://theses.edel.univ-poitiers.fr/theses/2009/Andami-Ovono-Armel/2009-Andami-Ovono-Armel-These.pdf.
Testo completoThis thesis is devoted to a quasilinear parabolic equation in which the diffusion is defined by the length of different non local interactions. As regards stationary problem, having shown the results of existence, uniqueness and continuity. We introduce a general criterion of inversibility later depending on parameter, this very important criterion is going to allow us in example of application to find well known results when parameter will be equal to the diameter of domain. We give then a fundamental result of comparison of solutions in the case of radial symmetrical solutions and a general implementation of count of solutions. Finally we give some numerical applications using a method of fixed point and Newton’s method to illustrate these results. As regards parabolic problem having shown existence of global attractor associated to our problem, we show an estimate L∞ of solution according to estimate Lq, q >1 by using Moser’s iteration
Torrenti, Jean-Michel. "Comportement multiaxial du béton : aspects expérimentaux et modélisation". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1987. http://tel.archives-ouvertes.fr/tel-00529740.
Testo completoPinto, Barbosa Mônica. "Semi-rigidité des nœuds d'ossatures en béton armé : simulations numériques". Lyon, INSA, 1992. http://www.theses.fr/1992ISAL0035.
Testo completoWithin the framework of finite element modelling of reinforced concrete structure the present study investigates the behaviour of beam-column connexion submitted alternate cyclic loading. The objective of this work is to simulate the behaviour of a frame Joint, to show the mechanisms observed and to contribute to the construction of models which takes them into account. This report is structured in three chapters : The first chapter presents a state-of-the-art of the experimental and numerical studies in this field, with particular reference to the semi-rigidity concept. It includes a discussion of the mechanisms taken into account in the design of frame Joints, and points out the assumptions and options selected. In the second part, the analytical models used are presented, as well as the numerical methods which are best suited. The last chapter is dedicated to the numerical simulation of the reinforced concrete frame joints under alternate cyclic loading. The deformation mechanisms are exemplified and a number of recommendations towards research needs are proposed
Furet, Agathe. "Modélisations expérimentale et numérique d'ouvrages pare-blocs modulaires : Application à la technologie Bloc Armé®". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI038.
Testo completoThis Cifre thesis investigates the impact response of protective structures based on the Bloc Armé® technology, developed by Géolithe Innov and Géolithe. This structure is made of concrete blocks linked by vertical and horizontal metal reinforcements. The main innovation lies in the reinforcement system which ensures the bonding of the blocks and gives the structure an ability to distribute the forces and dissipate energy.Two types of real-scale experiments permit to characterize the dynamic response of the structure. Firstly, the structure laid horizontally on a support layer is subjected to high- energy impacts (2000 kJ) by freely dropping of a projectile. Secondly, lower energy impact tests (125 kJ) are carried out by horizontal impact on a vertical wall of limited dimensions. Reduced models of the structure, at ¼ scale, are also tested under impact in the laboratory. This campaign permits to test many walls of different configurations under various impact conditions. These experimental campaigns illustrate the deformation mechanisms under localized dynamic solicitation for this kind of articulated structure. The different displacement modes of vertical walls and several phenomena dissipating impact energy are highlighted and quantified. The numerous measurements made during the tests constitute an important experimental database, supporting the development of the numerical model.A numerical model, developed with the finite differences method, is proposed for this structure. A realistic approach is followed for the modeling: each element of the structure is modeled explicitly. A simple model is deliberately considered for the concrete constituting the blocks. The model is calibrated based on values from the literature and measurements made specifically. The comparison of impact simulations results with experimental ones attests of the ability of the model in reproducing the global dynamic behavior of the structure and in estimating its residual displacement, in particular. The model quantifies the energy dissipation resulting from plasticization of the concrete blocks and from friction in the structure.The model is then used to simulate the response of walls of various geometries and under high energy impact. The outlooks of this work are to propose a robust model able to simulate the structure response to impacts with energies up to 5,000 kJ, considering structures with complex geometries
Matallah, Mohammed. "Modélisation numérique de l'endommagement anisotrope et unilatéral dans les structures en béton". Pau, 2006. http://www.theses.fr/2006PAUU3030.
Testo completoThe main objective of this work is the development of a new model coupled damage and inelasticity. The model is aimed to be used for damage and fracture analysis of concrete and reinforced concrete, as well as satisfying the industrial applications requirements. Firstly, a critical analysis based on mathematical and numerical complexities of different approaches is presented. Furthermore, a novel approach is proposed where an internal variable called the Unitary Crack Opening (UCO) is introduced to describe the evolution of inelastic strains. Taken as anisotropic, The UCO variable is coupled with a sacalar variable D ( which characterize an isotropic damage) to produce a good description of the crack induced anisotrpy. Hence, the crack closure effect is also taken into account. The UCO variable is related to the inelastic strains using a function S called the Crack Opening Indicator. When S=0 (which means that cracks are closed), the history of inelastic strains and damage are retained but their effect is deactivated due to the present of function S (D =DS =0). The model is developed based on a thermodynamic approach where its mathematical basis are presented and explained in detail. The novel approach developed here could be used to investigate the damage-permeability coupling
Belbachir, Ahmed. "Etude Expérimentale et Numérique de l’effet d’échelle dans les structures en béton armé soumises au cisaillement". Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0022/document.
Testo completoThe shear strength of reinforced concrete elements remains a subject of great interest for the civil engineering structures. During service,most structural elements are subjected to shear and /or punching stresses with an increased risk of brittle failure. Different methods of calculation of shear strengths exist but have considerable discrepancy especially for the structural elements without transverse reinforcement. It is mainly by not taking into consideration all the mechanisms which are involved in the shear behavior. The objective of thisdoctoral thesis is to contribute towards the understanding of the shear force transfer mechanisms in reinforced concrete beams. For this,an experimental campaign is carried out on reinforced concrete beams without transverse reinforcement and of different geometrically similar sizes in order to investigate the size effect on the shear force. The cracking process manifested by thepresence of a diagonal crack is analyzed by two experimental techniques: Digital Image Correlation and Acoustic Emission. By combining the results of the digital image correlation and the strain gauges glued on the longitudinal reinforcement, it is possible to distinguish the contribution of the aggregate interlocking mechanism and the dowel action on the transfer of shear forces. The influence of size effect on each transfer mechanism is analysed by simplified numerical and empirical models based on experimental results at the local scale. The results confirm that the aggregate interlocking mechanism plays a critical role in the contribution to shear strength for reinforced concrete elements without transverse reinforcement. This contribution depends essentially on the kinematic variables (crack opening and sliding) and the angle of inclination of the diagonal crack. This mechanism is strongly dependent on the size of the element and the shape of the crack
Iskef, Alaa Eddin. "Technologies informatiques pour l'étude du comportement expérimental et numérique d'un assemblage poutre-poteau en béton armé". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN015/document.
Testo completoThe behavior of reinforced concrete beam-column joints and their influence on the strength of the structures under cyclic or seismic loadings has been the subject of several investigations in recent years. However, the behavior of that part of the structure remains far from being mastered due to the complexity of the assembly involving several physical phenomena and due to the lack of exhaustive experimental data. This work aims to implement and provide a reliable and dense experimental database whose vocation is to provide access to an experimental benchmark to enable the modeling and validation of the behavior of these assemblies
BUZENAC, VERONIQUE. "Algorithmes adaptatifs pour l'identification de modeles arma a l'aide des statistiques d'ordre superieur". Cergy-Pontoise, 1996. http://www.theses.fr/1996CERG0010.
Testo completoCrambuer, Romain. "Contribution à l'identification de l'amortissement : approches expérimentales et numériques". Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2013. http://tel.archives-ouvertes.fr/tel-00957320.
Testo completoLoukil, Olfa. "Etude expérimentale et numérique de la dégradation d'éléments structurels en béton armé par corrosion sous courant imposé". Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1138/document.
Testo completoCorrosion of steel in reinforced concrete generates iron oxides which induce tensile stresses at the steel/concrete interface leading to the concrete cover cracking and loss of reinforcing bar cross-section. The evaluation of such pathology remains difficult and consequently limits the assessment of the structure serviceability, the knowledge on the degradation evolution, and the choice of a suitable repair method. The aim of this study is to correlate internal degradations (corrosion products formation and concrete cracking) induced by steel corrosion to external degradations (concrete cracking).The experimental program aims to determine these degradation mechanisms. The accelerated corrosion tests are carried out on reinforced concrete specimens in the presence of chloride ions by applying a constant current using three current densities (50,100 and 200 µA/cm²) during different exposure periods.Electrochemical properties of reinforced concrete specimens are determined before and after the accelerated corrosion tests. The quantitative evaluation of the corrosion products at the steel/concrete interface based on SEM observations (microscopic scale) demonstrates an important heterogeneity in the distribution and thicknesses (between 0 and 1584 µm). This heterogeneity can be explained by the evolution of anodic and cathodic zones due to different factors such as the non symmetric geometry of the specimens, the accelerated corrosion test environment (moisture, chloride ions and oxygen gradients), and the characteristics of concrete (aggregates, porosity).The internal (angular position, width, and length of cracks) and external crack patterns (maximum crack width) induced by the formation of corrosion products are analyzed. One to five internal cracks are identified in the internal crack patterns and they are classified in three groups. The first and second groups contain horizontal and vertical cracks which propagate in the direction of the shortest concrete cover. The third group is constituted of oblique cracks which are located in the opposite side of the horizontal cracks. The widths of the internal cracks range between 0.1 to 0.4 mm and their lengths between 1 to 3 cm. The maximum external crack widths are between 0.1 to 0.7 mm and are located on the shortest cover sides of the specimens.The maximum effort applied during the pull-out tests decreases with increasing levels of corrosion. However, the corrosion levels reach during the tests are too low to affect the steel/concrete interface behavior. The failure mode identified during the testing is concrete splitting failure regardless the corrosion level. A cause/effect scenario is proposed between steel corrosion and the mechanical induced degradation considering all experimental results.Based on experimental results, two models are proposed. The first one is developed to explain corrosion initiation and propagation. This model is able to determine the corrosion initiation time for each current density.The second model analyses the concrete cover mechanical behavior. The numerical results show that taking into account only the thickness of corrosion products (as an experimental input) does not generate a numerical cracking pattern similar to the experimental one. Then, complementary calculations considering a different distribution of the corrosion product’s thicknesses allow enhancing the agreement between experimental and numerical results
Benzerzour, Mahfoud. "Étude expérimentale et numérique du renforcement des tabliers de ponts en béton armé par des rechargements adhérents". Artois, 2004. http://www.theses.fr/2004ARTO0208.
Testo completoThe work developed in this report is part of research programme of the University of Sherbrooke, the purpose of which is to make technical recommendations for the durable repair of slabs of bridge deck. Following a bibliographical synthesis, we led a study in laboratory to analyze the structural behaviour of reinforced concrete slabs repaired using an adherent overlaying. The experimentation rested on a pilot slab and four slabs overlay according to different configurations (thickness of concrete, reinforcemen steel, anchorings). These slabs underwent several cycles of static and cyclic loading in pure bending in order to follow their behaviors in time. The experimental results made it possible to appreciate the good performance of three of the four configurations on the debonding of repair and the structural behavior of the slabs. To consolidate the noted were used two computer codes by finite elements (MSC. , MARC/MENTAT, ABAQUS 6. 4. 1) for, on the one hand, reproducing and to validate structural slabs repaired and for, on the other hand, analysing comprise it the constraints generated on the interface support-overlaying. The whole of the work realised within the framework of this thesis makes it possible to propose new techniques of repair of slabs of reinforced concrete bridge decks
Ali, Harith abdullah ali. "Etude expérimentale et numérique des poutres continues en béton armé renforcées ou réparées par collage des matériaux composites". Thesis, Reims, 2017. http://www.theses.fr/2017REIMS034/document.
Testo completoThe flexural strengthening of RC beams by external bonding of composite materials has proved to be an efficient and practical technique. This thesis presents a study on the flexural performance of reinforced concrete continuous beams with three spans repaired or strengthened by bonding carbon fiber reinforced polymer (CFRP) or glass fiber reinforced polymer (GFRP). The experimental program consists of two groups. Group-1 consists of eight beams and group-2 consists of eight beams. In each group, there is a reference beam, unreinforced beam. All beams have the same length of 9m and the same section of 15x25 (cm). The experimental tests with the monotonic loading were carried out using a 1000 kN press. The parameters studied are effect of reinforcement by CFRP and GFRP, the optimum thickness of the strengthening, repair efficiency of the beams damaged by CFRP and GFRP, mechanical behavior, the rupture modes of strengthened reinforced concrete beams. Experimental tests and calculations by numerical simulation were carried out. Five modes of the breaking of the beams were observed. The maximum strength of a beam can be improved by 14.8 and 33.0% for beams reinforced by CFRP bonding and between 7.2 and 11.8% by bonding GFRP. There is an optimum thickness of the reinforcement in the three spans of the beam. The fully damaged beam can be repaired at 100%. The maximum bending moment of the damaged and repaired beam becomes greater than that of the reference beam. A numerical study, using the finite element method with the help of ABAQUS software, on strengthening the continuous concrete beams, was also carried out
Zhao, Guoqiang. "Etude expérimentale et numérique de la résistance à l'effondrement progressif de sous-assemblages poteaux-poutres en béton armé". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI043/document.
Testo completoImportant buildings may be subjected to accidental loads, such as explosions or impacts, during their service life. It is, therefore, necessary not only to evaluate their safety under traditional loads and seismic action. The structural performances related to progressive collapse scenarios need to be investigated.The study of progressive collapse involves a dynamic problem, but unfortunately dynamic experiments on the behavior of the civil engineering structures under dynamic conditions are rare. In this research, beam-column sub-assemblage specimens were tested under dynamic load. The loading program consists in placing a large mass, as a dead load, on the top of the middle column of a beam-column sub-assemblage. The support under the middle column is suddenly removed for simulating the sudden loss of a column and the damage that will result in the structure. The loading system and supporting devices were designed specially for this test. The upper dead load can be changed by increasing or decreasing the applied masse to different specimens. The supports for the side column have a controlled rigidity in the horizontal direction and are designed to restrain rotation of the side-column. Thus, the boundary conditions are supposed to be similar to real situations. During the test, a laser was installed under the middle pillar to collect the falling velocity and a high-speed camera was used to visualize the whole process of the component failure process. The images obtained from the camera were processed by Digital Image Correlation (DIC) technology to get the corresponding displacements and strain fields. By these means, all the information of the structure under dynamic loading was captured and recorded, such as the period of vibration, frequency, velocity and displacement. Based on these experimental data, the effect of section and span of the specimen on dynamic response and damage mode was discussed. Time history of resistance force curves was produced. Compared with previous published quasi-static experiments in terms of structural mechanisms, crack patterns, damage mode, it shows the experimental results from beam-column assemblage with the designed support device can be used to analyze the behavior of the local structure in the entire frame.In addition, numerical simulations were developed for simulating the failing process of the structure. A technique named “connector” was proposed into beam-column finite element model by adding a series of springs to investigate the interaction between steel rebars and concrete. A concrete damage model, named DFH-KST model, was used to characterize the development of concrete crack and damage. The versatility of the adopted methodology allows assessing the influence of the material nonlinear behavior and the geometry of the tested structure. Calibration and validation studies show that the proposed model can successfully represent the resistance of structure and behavior. Furthermore, the transverse component effect on the resistance to progressive collapse was discussed
Nait-Rabah, Ouahcène. "Simulation numérique du comportement non-linéaire des ossatures spatiales : application aux structures en béton armé, en béton précontraint et mixtes". Châtenay-Malabry, Ecole centrale de Paris, 1990. http://www.theses.fr/1990ECAP0151.
Testo completoVoitus, Fabrice. "Étude de la faisabilité des conditions aux limites latérales bien posées et transparentes dans la dynamique des modèles Aladin et Arome". Toulouse 3, 2008. http://thesesups.ups-tlse.fr/843/.
Testo completoHeinfling, Grégory. "Contribution à la modélisation numérique du comportement du béton et des structures en béton armé sous sollicitations thermo-mécaniques à hautes températures". Lyon, INSA, 1998. http://www.theses.fr/1998ISAL0002.
Testo completoThis work concerns the development of a numerical model for concrete under tire or nuclear accident conditions. Within the temperature range concerned (20°C-1200°C), the behavior of concrete is affected by the physical and chemical changes of its microstructure. Within the framework of an uncoupled thermo mechanical analysis, the phenomena that have to be accounted for are the temperature dependency of the thermal and mechanical properties of concrete as well as the dependency of the response of concrete on the combined thermal and mechanical loading history. A thermo plasticity based model is proposed for the compressive and the cracking behavior of concrete. The irreversible variations of the properties of concrete are introduced. A multisurface plasticity criterion which accounts for the increasing sensitivity of compressive strength to hydrostatic pressure is developed. The pathological mesh dependency of the numerical solution is partially solved with help of the Hillerborg method. A phenomenological model is used for the evaluation of the thermo mechanical interaction strains. Structures submitted to high temperatures are analyzed. The capability of the model to describe the load and temperature history dependency of the response is checked. The effects of different hypotheses concerning the evolution of the fracture energy of concrete are studied. The behavior of a nuclear power plant raft in accidental conditions is analyzed. The results emphasize the importance of the thermo mechanical interaction on the predicted behavior of the structures. A contribution to the analysis of the spalling of concrete at high temperatures is proposed. The concrete is modeled within the framework of the mechanics of porous media. The thermoplastic model is a pp lied to the analysis of the skeleton through the effective stress. A simplified method for the evaluation of pore pressures and Biot coefficient is proposed and the behavior of concrete specimens is analyzed
Jehel, Pierre. "Modélisation numérique des phénomènes d'amortissement par dissipation d'énergie matérielle dans les structures de type portique en béton armé sous séisme". Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2009. http://tel.archives-ouvertes.fr/tel-00477015.
Testo completoLeroux, Armand. "Modèle multiaxial d'endommagement anisotrope : gestion numérique de la rupture et application à la ruine de structures en béton armé sous impacts". Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00824314.
Testo completoLimam, Sophia. "Etudes expérimentales et numériques du comportement des dalles épaisses en béton armé avec épingles sous cisaillement : Application aux bâtiments nucléaires". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI006/document.
Testo completoThis thesis, based on experimentation and numerical modeling aims at a better understanding of the behaviour of reinforced concrete slabs equipped with shear reinforcements, by measuring the effect of stirrups on their shear strength. A bibliographical synthesis was first carried out to highlight the parameters acting on the shear stress through the results of previous work and studies such as the characteristic resistance of concrete in compression, the rate of longitudinal and transverse reinforcements, the shear to span ratio the size of the aggregates and the applying of an axial load. The experimental campaign was then carried out on thirty slabs including 9 slabs without shear reinforcement and 21 slabs with stirrups shared in four series, the first designed to study the global and local shear behaviour, the second to analyze the interaction of the stirrups with the longitudinal reinforcement, the third to study the effect of an axial effort on the shear strength and to check whether there is interference from the shear reinforcement on the behaviour of axial effort and the fourth to study the effect of meshing of aggregates by varying the size of their maximum diameter. The results confirm the shear gain through the adding of stirrups and also their interaction with longitudinal reinforcement and axial compression. Also, the stirrups cancel the effect of increasing the diameter of concrete aggregates. The experimental results are compared with the forecasts based on Eurocode 2, the French national Annex, the Fib Model Code 2010 and the ACI 318-14. The results show that overall the French approach ANF (avg = 1.00, std = 0.08) and the fib Model Code 2010 give very close results of experimental values. The EC2 also gives acceptable results with reasonable security margins. Comparison of the analytical results obtained with the EC2, the ACI 318-14, the Fib Model Code shows that both the ANF is successful; The best average of the "experimental shear strength and the numerical shear strength ratio (1.014) was obtained with the ANF (0.03). The modeling of slabs, using the elastoplastic concrete model with damage through ABAQUS EXPLICIT gives results comparable to the experimental results, not only for the determination of the ultimate load and the maximum shear strength but also for the failure mode which is similar to the experimental one
Takorabet, Nacer. "Influence des interfaces sur le comportement des structures composites en béton armé : étude expérimentale et modélisation numérique par la méthode des éléments finis". Châtenay-Malabry, Ecole centrale de Paris, 1989. http://www.theses.fr/1989ECAP0106.
Testo completoGermain, Jean-Baptiste. "Le développement des outils numériques dans la communication publique des départements ministériels, le cas particulier du ministère de la défense". Thesis, Paris 2, 2018. http://www.theses.fr/2018PA020086/document.
Testo completoIn 1196, the President of the French republic, Jacques Chirac suspends the military service. This action has for consequences to cut definitely the link between French army and the youth. Ever since the French army search a way for recruit young people. The ministry of defense has a bad reputation and suffers of a stereotypical image. For sort out of this deficit of renown the French army decide to use the digital tools for speak at the youth. Nowadays the young people can live without smartphone, internet or Facebook. For that the French ministry of Defense tries to invade the mediatized battlefield
Lé, Benoît. "Contribution à la simulation numérique des structures en béton armé : utilisation de fonctions de niveau pour la modélisation de la fissuration et des renforts". Thesis, Ecole centrale de Nantes, 2016. http://www.theses.fr/2016ECDN0003/document.
Testo completoPrediction of cracking is a key point for the analysis ofreinforced concrete structures, which requires the use of Modeling and numerical simulation. The analysis of reinforced concrete structures using the finite element method raises two issues: on one hand, few models areable to deal with the initiation, the propagation and the opening of cracks, on the other hand the diameter of thereinforcements which is usually small compared to the dimensions of the structures necessitates very fine meshes. Some solutions to these two problematics areproposed, based on the use of level set functions.Damage and cracking of concrete are modeled using theThick Level Set (TLS) approach. This method,developped as a mean to regularize local damagemodels, uses a level set to introduce a characteristic length. It makes the location of the cracks easy, whichallows to enrich the displacement field with the eXtendedFinite Element Method (X-FEM) in order to model the macro-cracks opening. Concerning the modeling of thereinforcements, a new multidimensionnal approach isproposed. A volumic representation of the reinforcements with the X-FEM method is used in the zones of interest to get accurate results while simplifying the meshing process, whereas a lineic representation isused elsewhere to decrease the number of degrees of freedom. The developed transition method insures the consistency of the results
Dinh, Thi Thanh Xuan. "Etude expérimentale et numérique de l'approche physico-chimique pour le matériau cimentaire soumis au dioxyde de carbone (CO2)". Thesis, Evry-Val d'Essonne, 2012. http://www.theses.fr/2012EVRY0019/document.
Testo completoToday, the durability of structures in cementitious materials is an important factor in the areas of civil engineering and industrial engineering. It is influenced not only by mechanical loads but also by the environment (pollution, rain ...). These influences become more important when one has to guarantee a service life of materials for a great period. The mechanism of chemical degradation of the cementitious material is a progressive decalcification over time in contact with aggressive environments (e.g. attack by chlorides, by sulfates, freeze-thaw cycles, alkali reaction). This degradation causes the variation in the porosity of the concrete that modifies the physico-chemical and mechanical properties. On the one hand, the change in porosity accelerates the transport of substances and causes an acceleration of the dissolution of hydrates (notably portlandite). Moreover, this induces a change in mechanical properties, especially shrinkage of carbonation. In addition, the mechanical stress creating microcracks that may be factors accelerating the process of chemical degradation. This work is carried out to study the physicochemical phenomenon of carbonation on cement-based materials such as mortars and cement pastes based on CEM I and CEM III. The main purpose of this study is to characterize experimentally and numerically the effects of carbon dioxide (CO2) on the mechanical properties and durability of cementitious material. In the experimental part, we take into account some important parameters such as shrinkage, variation of porosity and variation of mass in terms of different concentrations of carbon dioxide (CO2): 5%, 10%, 13%, 15%, 17%, 20%. The numerical model based on the physico-chemical approach by Bary and Sellier (2004) allows us to validate the parameters that influence the carbonation in cementitious material as rate of water saturation, partial pressure of carbon dioxide (CO2), calcium ion concentration and porosity. This confirms that the transfer of carbon dioxide (CO2) in gas phase couple with transfers of liquid water and calcium ions Ca2 + in aqueous solution during carbonation
Truong, Ba Tam. "Formulation, performances mécaniques, et applications, d’un matériau TRC pour le renforcement et la réparation de structures en béton/et béton armé : Approches expérimentale et numérique". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI076/document.
Testo completoThis study, using both experimental and numerical approaches, will help to better understand the behavior of structure strengthened/repaired by composite based on mineral matrix. It especially focuses on the study of a new coating for drinkable water reservoirs without bisphenol A. The main objective of this thesis is development of a mineral matrix composite. Feasibility, performances and behavior of composite are examined. The experimental program involves different levels of analysis. At material level, the formulation and characterization of a mineral matrix are studied. At structure level, the application of this composite for the strengthening and repair of concrete and reinforced concrete structures is considered. A bending experiment on concrete specimens and the study of twelve reinforced concrete beams submitted to four point bending load, allows presenting good disposition in terms of bearing capacity. Secondly, the local analysis highlights the efficacy of the composite to bridge the crack and stop opening propagation. The effect of two different conservation conditions of beams with TRC (immersion in water compared to in air) was studied. The objective is evaluating the pertinence of TRC conserving in the water environment to apply in the concrete water reservoir structure. The effect evaluation of load history of structures on the efficacy strengthened/repaired of TRC composite is presented. It seems that the pre-cracking does not influence on the qualitative and quantitative behavior of the structure. Concerning the numerical approach, this work aims to establish a numerical model of concrete structure and reinforced concrete structure strengthened/repaired by TRC composite materials. The model, which is based on non-linear behavior laws for the constitutive materials (concrete, steel and TRC composite), is compared, at several scales, with experimental results. The good agreement, both qualitative and quantitative, between the model used and the results as expressed in the load-deflection curves validates the proposed model at a global scale. At local level (longitudinal deformation of the steel, deformation of the concrete, deformation of the TRC, cracks opening…) the digital-experimental comparison confirms a good qualitative and, the quantitative agreement. Finally, the parametric study allows to evaluate the influence of the thickness of the composite TRC (indirectly, the reinforcement ratio of beam), and the influence of the pre-cracking configuration on the global and local behavior of the structure
Lemarignier, Thierry. "Fissuration des chaussées en béton armé continu au jeune âge". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1996. http://tel.archives-ouvertes.fr/tel-00523285.
Testo completoLemarignier, Thierry. "Fissuration des chaussées en béton armé continu au jeune âge". Phd thesis, Marne-la-vallée, ENPC, 1996. http://www.theses.fr/1996ENPC9610.
Testo completoThe present study will contribute to understanding of mechanical behavior of stell-reinforced-concrete based pavements vs. Microcracking. Based upon the knowledge of concrete and the griping between concrete and stell, contact problems are investigated according to the finite-element method. The griping experiments allow us to achieve a new test : the ABA test. The present results account for accurate parameters involved in the numerical model for steel-concrete interface law. For a better understanding of cracking origins, an experimental device and original process were perfected to simulate this kind of behavior in life-size in laboratory. It brings to therefore some thermal strains at earlier stage during concrete setting. Otherwise the following points were shown : the importance of concrete section or steel content ; the importance of the friction between the slab and the holder ; the influence of the kind of framework used on the craking development. Furthermore, development of mechanical characteristics and free shrinkage were determined on references. And, a comparison was undertaken between experimental and calculated results
Meftah, Fekri. "Contribution à l'étude numérique des modes localises de rupture dans les structures en béton de type poutres : approche multicouches par la plasticité au gradient". Lyon, INSA, 1997. http://www.theses.fr/1997ISAL0005.
Testo completoStructural geometrical exhibit stain softening due to non-homogeneous deformations. Softening behavior is a precursor to failure and involves localization of deformation. When it is taken into account, in a standard continuum theories, such as convention plasticity, the strain softening phenomenon leads to ill-posed boundary or initial value problems, since the governing equations loose ellipticity or hyperbolicity. Therefore, numerical simulations suffer from extreme mesh dependence. The localization zone is complexly determined by the discretization and convergence to unique solution in no more obtained. In this work, the gradient-dependent plasticity theory is used as a localization limiter to prevent standard continuum deficiency. The essential feature of this theory is the dependence of the yield function upon the second order spatial gradient of the plastic strain measure. This term allows keeping well-posed character of the problem during localization. Furthermore, the gradient dependence makes difficult to determine the increments of the plastic multiplier, since the consistency condition is a partial differential equation. Therefore, it is satisfied in a weak or distributed sense, leading to a mixed formulation where the plastic strain filed is discretized in addition to the usual discretization of the displacement filed. In this contribution, a layered approach based on gradient plasticity is developed. A gradient dependent layered beam finite element is then elaborated. It allows ensuring numerical solution which is mesh independent. Application to concrete and reinforced concrete beams under static and impulsive loading ie presented to validate and illustrate the approach. The use of the fracture energy as a material parameter and the possibility of the model to describe the size effect are also scrutinized
Hameed, Rashid. "Apport d'un renfort de fibres sur les performances des structures en béton armé pour les applications parasismiques". Toulouse 3, 2010. http://thesesups.ups-tlse.fr/944/.
Testo completoIn October 2005, an earthquake 7. 4 on Richter scale hit the northern area of Pakistan and caused 80 thousand deaths and severe damage to structures. Poor construction material and lack of seismic design considerations were the two major reasons of this severe damage. For structures, surviving a seismic event depends mainly on their capacity for energy dissipation. The greater the energy dissipated, the better the structure performance. In Pakistan, usual practice is to use normal strength reinforced concrete as a construction material. One of the main objectives of this study is to respond to an important question: is it possible to improve the properties of normal strength reinforced concrete for the seismic application? Fiber reinforcement is commonly used to provide toughness and ductility to brittle cementitious matrices. The present study aims to evaluate the contribution of two different types of metallic fibers in hybrid form to improve the mechanical properties, energy dissipation in particular, of normal strength reinforced concrete. A special kind of fiber (FibraFlex) capable of restraining micro-cracking effectively and commonly used carbon steel hooked-ends fibers (Dramix) capable of restraining macro-cracking have been investigated in mono and hybrid forms. The first is qualified as non-sliding fiber while the second is considered as sliding fiber. The maximum content of fiber in mono and hybrid form investigated in this research study was 40 kg/m3 and 80 kg/m3 respectively. The results of reverse cyclic flexural loading tests performed on reinforced fibrous concrete beams having conventional steel ratio (1) equal to 0. 19%, showed that the FibraFlex fibers provide an important gain in energy dissipation at low levels of displacement amplitude. At large displacement amplitude, role of Dramix fibers is more significant to improve energy dissipation. As a result of different action of each fiber at different displacement amplitude levels, a significant increase in energy dissipation capacity of RC beam was registered when both fibers were used in hybrid form at content of 80 kg/m3 (40 kg/m3 of each type of fiber). A 3D numerical model to predict the behaviour of concrete matrix reinforced with sliding and non-sliding fibers both in mono and hybrid forms is proposed. Considering fiber reinforced concrete as two phases composite, constitutive behaviour laws of plain concrete and sliding fibers were described and then they were combined according to anisotropic damage theory to predict the mechanical behaviour of FRC. The behaviour law used for the plain concrete is based on damage and plasticity theories. The behaviour law of the action of sliding fibers (Dramix) in the matrix is based on the effective stress carried by the fibers while bridging the crack which depends on a damage parameter related to on one hand on the content and the mechanical properties of the fiber and on the other hand, on the fiber-matrix bond. To treat non-sliding fiber, a simplified approach is proposed in which constitutive law of plain concrete is used with increased value of fracture energy obtained from the direct tensile test on concrete reinforced with non-sliding fibers. Finally, to simulate the behaviour of hybrid fiber reinforced concrete, approaches to model sliding and non-sliding fibers are combined without any additive equation. A simplified approach to model the steel-concrete interface in case of reinforced concrete elements has been also proposed. This approach considers the steel-concrete interface as bond element with isotropic elasto-plastic properties. Infect, the bond element replace the steel bar area and steel bar is modelled as uniaxial bar element with elastic-plastic perfect behaviour law. Fitting of this approach was done by simulating pull-out and uniaxial tensile loading tests on RC specimens. 3D model for FRC composites and simplified approach for steel-concrete interface with fitted parameters were then used to simulate the flexural behaviour of reinforced fibrous concrete beam. Modelling results showed good agreement with experimental results
Shafiee, Sasan. "Simulation numérique du comportement des sols cloués. Interaction sol-renforcement et comportement de l'ouvrage". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1986. http://tel.archives-ouvertes.fr/tel-00520679.
Testo completoLaplante, Marc-Antoine. "Courbes de fragilité pour la détermination de la vulnérabilité sismique de bâtiments en maçonnerie armée à partir du spectre conditionnel". Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9438.
Testo completoNechnech, Wahid. "Contribution à l'étude numérique du comportement du béton et des structures en béton armé soumises à des sollicitations thermiques et mécaniques couplées : une approche thermo-élasto-plastique endommageable". Lyon, INSA, 2000. http://theses.insa-lyon.fr/publication/2000ISAL0084/these.pdf.
Testo completoThe aim of this research is the development of an Finite Element model for the analysis of reinforced concrete structures under thermal, mechanical loadings or any combination of them. An available synthesis of results on the concrete behavior under thermal solicitation is exposed. The different behavior of concrete that can be founded notably in thermo-mechanical analysis (Damage, unilateral phenomenon, thermo-mechanical interaction) are underlined. The various families of modeling are analyzed thereafter while underlining the important aspects of the behavior that each one can retranscribe. A new thermo-plastic damage model for plain concrete subjected to combined thermal and cyclic loading is developed using the concept of plastic-work-hardening and stiffness degradation in continuum damage mechanics. Two damage variables are used: the first one for mechanical action and the second one for thermal action. Further, thermo-mechanical interaction strains have been introduced to describe the influence of mech
Samson, Mathias. "Étude expérimentale et numérique, en écoulement instationnaire, du trajet des bras en crawl à différentes allures de nage". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2270/document.
Testo completoFront crawl is a swimming stroke used at swimming competitions at freestyle different paces (sprint, middle distance and long distance). Propulsion in this stroke is achieved primarily by the forearm and hand. Accelerations of these segments, in a fluid at rest, generate complex flow that causes propulsive hydrodynamic forces. Analysis of this flow is necessary to understand the main mechanisms of propulsion. In this context, the "kinematic flow parameters" (velocity, acceleration and orientation of the hand, angles of attack and sweepback) have been defined to analyze and compare the different arm motions and their effects on propulsion. Two of the main axes of this investigation were to determine whether these parameters vary depending on the pace, and also to determine what kinematic parameters were most prominent in the generation of propulsive mechanisms. To this end, an optoelectronic system of motion capture was used to measure these parameters on 17 expert swimmers in free swimming. Furthermore, the flow generated by the experimentally acquired arm trajectory, at different swimming paces, was simulated by an unsteady numerical solution of the Navier-Stokes equations. Finally, tethered swimming experiments were carried out to measure the propulsive forces.The increase in forward velocity by increasing swimming pace can be explained by lower durations of non propulsive phases (entry and stretch) rather than by the generation of higher forces during the most propulsive phases (insweep and upsweep)
Averbuch, Daniel. "Approche du dimensionnement des structures en béton armé par le calcul à la rupture". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1996. http://tel.archives-ouvertes.fr/tel-00523025.
Testo completoNana, Wendpanga Serge Auguste. "Etudes expérimentales et numériques du comportement des dalles épaisses en béton armé sous chargement de cisaillement et interaction cisaillement/effet de membrane : Application aux bâtiments nucléaires". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI108/document.
Testo completoThis study, based on experiments and numerical modeling, aims at a better understanding of the shear behavior of reinforced concrete slabs. An experimental campaign was carried out on full-scale thick slabs typical of nuclear power plant slabs. These slabs without shear reinforcement are subjected to a quasi-static shear loading. The tests are carried out by varying different parameters that can influence the shear behavior: the concrete compressive strength, the slab depth, the bottom longitudinal and transverse reinforcement ratio, the concrete aggregate size, the loading plate length. The influence on shear behavior of compression or tension membrane forces has also been analyzed. The results of tests are then compared with the predictions of the calculation codes. These results first of all helped to answer the differences between the Eurocode 2 and the French National Annex concerning the prediction of the shear capacity of reinforced concrete slabs. The level of accuracy given by other shear dimensioning standards was also assessed: The American standard ACI 318-14, the AFCEN ETC-C 2010 code used for nuclear buildings, the fib-Model 2010 and the Critical Shear Crack Theory. Next, we evaluate the possibilities of a non-linear finite element analysis (EF) to reproduce the phenomenon of shear in slabs. An elastoplastic concrete model with damage was used and combined with a quasi-static analysis using an explicit resolution scheme. Appropriate nonlinear behavior laws of concrete with post-peak behaviors associated with an energy criterion were considered. The good agreement between the proposed model and the experimental results in terms of shear strength and failure modes allowed validating the proposed modeling. A parametric study was conducted based on the numerical proposed model with the same mechanical properties of concrete. Simplified laws allowing estimating the shear capacities according to the different parameters studied are proposed
Nguyen, Anh Quan. "Evaluation non destructive du gradient de teneur en eau dans les structures en béton armé par résistivité électrique". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30380/document.
Testo completoWe propose a new measurement procedure that allows drawing a resistivity curve as a function of the spacing between current electrode and potential electrode which is linked to the investigation depth and the water content gradient. The resistivity measurements above the rebars are performed and an inversion procedure to assess the resistivity gradient is carried out. For the experimental part two kinds of measurement are performed on concrete slabs (reinforced and unreinforced). Two gradient types are studied: drying and wetting. The presence of the reinforcement significantly decreases the measurement of the resistivity. The measurements show the interest of the proposed procedure for the study of the water content gradient. Two measurement results were considered in numerical analyses. The simulation shows that it is possible to assess the resistivity gradient and the electrochemical parameters of the rebar via the Butler-Volmer model
Pontiroli, Christophe. "Comportement au souffle des structures en béton armé : analyse expérimentale et modélisation". Cachan, Ecole normale supérieure, 1995. http://www.theses.fr/1995DENS0005.
Testo completoDesprez, Cédric. "Analyse et Réduction de la Vulnérabilité Sismique des Structures Existantes : Renforcement par Collage de Tissus de Fibres de Carbone (TFC)". Phd thesis, Grenoble INPG, 2010. http://tel.archives-ouvertes.fr/tel-00560438.
Testo completoSoyez, Laurent. "Contribution à l'étude du comportement des ouvrages de soutènement en sol renforcé, soumis à des charges d'exploitation ferroviaire (charges dynamiques et cycliques)". Phd thesis, Ecole Nationale des Ponts et Chaussées, 2009. http://tel.archives-ouvertes.fr/tel-00596015.
Testo completoDouk, Najib. "Approche numérique multi-échelle du renforcement de structures par matériaux composites textile-mortier (TRC) vis-à-vis de sollicitations thermo-mécaniques extrêmes (incendie)". Electronic Thesis or Diss., Lyon, 2019. http://www.theses.fr/2019LYSEE003.
Testo completoThis study addresses the state-of-the-art development and current understanding of reinforced concrete beams strengthened with TRC (Textile Reinforced Concrete) under thermo-mechanical loading, specifically in the case of fire. The present work is divided into several parts. The numerical work presented in this thesis contributes to the reinforcement of reinforced concrete structures using TRC in fire scenarios. A review of the current state of the art reveals that structural reinforcement in fire situations is largely reliant on unreliable solutions such as CFRP (Carbon Fiber Reinforced Polymer). Moreover, there is a scarcity of studies in the current literature regarding structural elements reinforced by TRC in fire conditions. This thesis focuses on thermo-mechanical numerical modeling of reinforced concrete beams reinforced with TRC. Two separate numerical models for thermal and thermomechanical analyses will be established and subsequently coupled. The4 development of the numerical models will proceed in two parts: first, a thermal component, followed by a thermomechanical component. Every thermal numerical investigation is founded on a certain degree of theory derived from the scale and phenomenology described. For concrete, two main scales of thermal modeling can be listed: microscopic, which considers concrete as a multi-phase porous material (solid, liquid, and gas), and macroscopic, which treats concrete as a homogeneous material. The thermal aspect of this work will be validated at the macro-level through numerical-experimental comparisons. The results of the thermal component will then be integrated into a thermo-mechanical model of a beam reinforced with TRC. The numerical models of the present work seek to enhance the understanding of the thermomechanical mechanisms involved in TRC reinforcement, such as the effect of bonding methods, the number of TRC layers, and failure causes. Furthermore, another section is dedicated to TRC reinforcement effects with thermal protection
Desprez, Cédric-Arthur. "Analyse et réduction de la vulnérabilité sismique des structures existantes : renforcement par collage de tissus de fibres de Carbone (TFC)". Grenoble INPG, 2010. http://www.theses.fr/2010INPG0115.
Testo completoIn structural engineering, the seismic vulnerability reduction of existing structures is an important issue. Retrofitting by Polymer Reinforced Fibres (FRP) is an interesting response in order to fulfil this aim. This paper presents a simplified modelling strategy to predict the behaviour of reinforced concrete structures upgrade with FRP. A nonlinear finite element method is used, based on multifiber beams with damage and plasticity models. Retrofitting of flexural element (wall, beam) and column confinement are studied. More specifically, a confined concrete constitutive law suitable for monotonic and cycling loadings is proposed. The model is inspired on two well-known concrete laws, one based on damage mechanics theory (La Borderie) and the other based on experimental studies (Eid & Paultre). Validation of the strategy is provided using two case studies: a retrofitted bridge pier and a vulnerability assessment on an existing building trough static (Pushover) and dynamic analysis
Germain, Olivier. "Contribution à l'analyse du comportement et au dimensionnement des colonnes élancées en béton armé". Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210894.
Testo completoInévitablement, cette diminution de la section transversale induit une augmentation de l’élancement et augmente ainsi les risques des instabilités de flambement.
A cette question de flambement, il faut adjoindre l’influence d’une préconception qui veut qu’une structure en béton à haute résistance soit moins ductile qu’une structure construite avec un béton normal !De ceci résulte la question à la base de ce travail :
« Peut-on arriver à diminuer la section transversale d’une colonne en utilisant des résistances de béton plus élevées tout en imposant la même valeur de capacité portante et en ne réduisant pas leur ductilité ?»
Afin de répondre à cette question, le travail s’est articulé autour de deux axes essentiels qui sont d’une part une campagne d’essais (afin d’obtenir des résultats fiables) sur 12 colonnes en béton armé à haute résistance (90N/mm²) d’élancement 74 et 82 dont l’excentricité de la charge est une variable, et d’autre part l’implémen- tation de deux programmes informa- tiques utilisant le principe de l’analyse au second ordre en vue de réaliser une étude paramétrique dont l’excentricité, la hauteur des colonnes, la proportion d’acier, la résistance du béton sont les variables.
Trop souvent encore, les ingénieurs de bureau d’études hésitent à effectuer un calcul au second ordre et placés devant la question des dimensions de section à donner à une colonne de hauteur et de capacité portante imposées, déterminent celles-ci pour se satisfaire d’un calcul au 1er ordre. Au terme de notre étude, nous avons montré que cette approche est loin d’être optimale, qu’il est possible, au prix d’un calcul au second ordre (mais il est fait à l’ordinateur), de tirer profit d’une augmentation de la résistance du béton pour réduire les dimensions des sections et aboutir en toute sécurité à un dimensionnement plus économique en consommation de matériaux (acier, béton, ciment).
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
Aouameur-Mesbah, Amel. "Analyse non-linéaire matérielle et géométrique des structures coques en béton armé sous chargements statiques et dynamiques". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1998. http://tel.archives-ouvertes.fr/tel-00529774.
Testo completoTherrien-Truchon, Julie. "Comportement sismique des murs de remplissage en maçonnerie de tuiles structurales d'argile". Mémoire, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/5503.
Testo completoPolania, Elliot. "Contribution à l'étude du comportement des planchers composites poutres - dalles alvéolées préfabriquées en béton". Toulouse, INSA, 2006. http://www.theses.fr/2006ISAT0019.
Testo completoHollow core slabs are generally supported by walls reinforced or prestressed concrete beams or metallic beams. Depending of the bending rigidity and forces applied on the floor, beams bending inducing a transversal deformation of hollow core slabs, so leading to transversal shear stresses. This mechanism is the cause of the reduction of shear strength of hollow core slabs, being able to go up to 70%. Contrary to, when hollow core slabs are supported on rigid supports, the hollow core slabs behave as a compression flange of the beam, thus increasing the bending and shear resistance of the composite T beam. It is essential to know the real behaviour of composites floors in order to elaborate simple and reliable design methods easy to apply. For that a coupled approach numerical simulation and experimentation has been chosen. The first part is dedicated to the numerical study of composites floors' behaviour. We could thus define the experimental tests and highlight the decrease of the shear strength according to the flexural stiffness of the support. The second part deals with the experimental study of the composites floors' behaviour. Two full scale tests have been carried out. The flexural stiffness of the support is the only difference. Those tests first allow validating the numerical results and second to highlight the decrease of the hollow core slabs' shear strength