Dissertations / Theses on the topic 'Flexion à trois points'
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Régal, Xavier. "Caractérisation du comportement en traction du béton sous fortes sollicitations : essais de flexion trois points aux barres de Hopkinson." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2003/document.
The concrete is one of the most widely used constructional materials. However, its tensile behavior in dynamic is yet not perfectly known. In order to design concrete structures and predict their collapse in the case of industrial accidents, it is mandatory to know its tensile strength. This property depends on the different solicitations to which the concrete can be exposed. In order to characterize the tensile strength of a R30A7 concrete and its dependence on the strain rate, three points bending tests are performed in static and dynamic cases. For this purpose, the most recent standards are used in the static tests. The dynamic ones are carried out with the split Hopkinson pressure bars. This device allows to perform dynamic tests with both the speed and effort loading measurements. Moreover a high speed camera is used to record these experiments in order to acquire full-field displacement measurements with the help of the digital image correlation. Tools using these fields are created to detect the apparition of the crack in one hand, and to follow the crack propagation in the other hand. All these experimental devices and the use of different models, some of which take in account the sample damage, make it possible to determinate the evolution of the tensile strength depending on the strain rate. This work brings forward the fact that ignoring the material damage increases the tensile strength obtain from the tests
Roudet, Francine. "Comportement en flexion trois points avec cisaillement prépondérant de composites verre-époxyde unidirectionnels : sous chargements monotone et cyclique." Lille 1, 1998. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1998/50376-1998-439.pdf.
Croston, Tania. "Etude expérimentale du comportement d'une poutre en béton armé en flexion trois points réparée par matériaux composites (approche probabiliste)." Phd thesis, Paris, ENSAM, 2006. http://pastel.archives-ouvertes.fr/pastel-00002602.
Bacon, Christophe. "Mesure de la ténacité dynamique de matériaux fragiles en flexion trois points à haute température, utilisation des barres de Hopkinson." Bordeaux 1, 1993. http://www.theses.fr/1993BOR10508.
BOUKHAROUBA, TAOUFIK PLUVINAGE G. "ETUDE DU COMPORTEMENT DES FISSURES DE FORME SEMI-ELLIPTIQUES ; APPLICATION AUX PLAQUES EN FLEXION TROIS POINTS ET AUX TUBES SOUS PRESSION INTERNE /." [S.l.] : [s.n.], 1995. ftp://ftp.scd.univ-metz.fr/pub/Theses/1995/Boukharouba.Taoufik.SMZ9516.pdf.
Feusier, Gilles. "Etude des propriétés mécaniques à haute température des cermets Ti(C,N)-Mo-Co par mesures de frottement intérieur et par essais de flexion trois points /." [S.l.] : [s.n.], 1997. http://library.epfl.ch/theses/?nr=1659.
Charpail, Estelle. "Analyse du comportement mécanique des côtes humaines en dynamique." Phd thesis, Paris, ENSAM, 2006. http://pastel.archives-ouvertes.fr/pastel-00002983.
Van, Hecke Elisabeth. "Contribution à l'étude des propriétés texturales des produits alimentaires alvéolés : mise au point de nouveaux capteurs." Compiègne, 1991. http://www.theses.fr/1991COMPD381.
Diet, Stéphane. "Mécanismes de rupture des côtes et critères de tolérance thoracique en choc automobile." Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2005. http://pastel.archives-ouvertes.fr/pastel-00568920.
Yang, Zhengtian. "Étude expérimentale de la fissuration hydrique d’un sol argileux." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0038.
The main objective of this experimental study is to better understand and characterize the shrinkage phenomenon and the cracking behavior of clay during drying, and to better understand the mechanism of crack initiation and propagation in clay under hydric loading. Kaolin K13, which is a pure kaolinite clay, was considered in our study. The research is devoted to two main parts, one related to drying shrinkage and the other to desiccation cracking.Experimental studies on drying shrinkage are conducted to determine the hydraulic properties and mechanical behavior of the studied material during the drying process. For this purpose, the hydric parameters including water content, void index and degree of saturation of small unsaturated clay samples with different suction levels were measured by the Kerdane tests. The test is based on measuring the solid volume by liquid displacement. The shrinkage curve and the water retention curve of the studied material were established after fitting the Fredlund and Van Genuchten formulas from the experimental results. The shrinkage deformation of the soil was studied by controlled desiccation tests using smooth supports. Controlled desiccation, using the salt solution method, allows samples to be subjected to the same desiccation path. Global and local deformations of are obtained by 2D-DIC and 3D-DIC. Finally, the local water content and the local suction of the sample are estimated from the local volume deformation coupled with the water retention curve and the shrinkage curve of our material.The second part of the study is devoted to the initiation and propagation of cracks under controlled desiccation of an initially saturated clay. In order to study the main factors influencing cracking and to compare with free shrinkage, the semi-rough substrate was used in controlled desiccation tests, so that the cracks produced in the different samples were captured by the DIC. The evolution of the cracks was first quantified by morphological and statistical studies of the cracks via Image-J software. The influence of the drying path and sample support on the water cracking behavior were also studied at the global sample scale by the DIC. The increase in mechanical strain within the sample, produced by the limiting effect of the support on shrinkage deformation, is one of the main causes of cracking. The distribution of local strains, the phenomenon of stress concentration (through the development of local strains), are studied and analyzed. Crack initiation occurs in local stress zones where the tensile limit of the soil is exceeded. The crack propagation behavior is due to the tensile stress zone at the crack tip. The cracking mechanism is defined by studying the principal direction of deformation. The observed cracks developed in the horizontal direction of the samples, with little effect of vertical deformation on their occurrence. The mode of failure is mainly mode I. More complex failure modes, mixed with mode I, also exist. The study of the cracking mechanism, especially the cracks caused by traction (mode I) was further investigated by indirect traction tests on clay beams. Beams with different levels of suction were subjected to three-point bending, which caused tensile cracks in their tensioned lower part. The maximum strength and maximum bending at cracking and the local tensile deformation related to cracking are studied, as well as the effect of suction on the strength of unsaturated clays
EVAIN, LAURENT. "Collisions de trois gros points sur une surface algebrique." Nice, 1997. http://www.theses.fr/1997NICE5070.
Spada, Danilo. "La perception de la musique : trois points de vue expérimentaux." Paris 10, 2004. http://www.theses.fr/2004PA100023.
The research moves from the domain of cognitive psychology (Lerdhal and Jackendoff, Irène Deliège, Michel Imberty) concerning the organisation and structuration of atonal compositions. Since these models are abstract and far from the elaboration processes of the auditor, the attention has been moved to the cognitive and emotional components in a strictly psychophysiological context (periferic physiological indices versus cognitive segmentations). The third study, the neurophysiological one, analyses the gamma band of EEG records thanks to non-linear methodology. The goals are the similarity indexes (SI in Bhattacharya and Petsche) in the recordings of different cortical areas during the audition of distinct musical development moments
Dagenais, Audrey. "Suites maximales de mutations vertes dans les carquois cycliques à trois points." Mémoire, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6576.
Aibinu, John. "Les trois essais sur les actifs bancaires : Points communs et risque systémique." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0085.
This thesis analyzes the impact of bank asset commonality on systemic risk. This study examines the impact of asset portfolio overlap on systemic risk in large U.S. BHCs. Results reveal a U-shaped relationship between asset commonality, individual probability of default, and systemic risk among banks. Lower asset commonality is linked to reduced risk, while higher commonality is detrimental to financial stability. Investigating liquid and illiquid assets confirms the U-shaped relationship. Our results further emphasize the importance of maintaining low asset commonality for financial stability during normal and crisis periods, as well as for banks with shorter funding maturities. The second chapter studies the impact of asset commonality on systemic risk under varying degrees of implementation of macroprudential policies using a cross-country sample. The primary objective of macroprudential policy is to reduce bank’s exposure to systemic risk arising from excessive credit growth, correlated failures, and other common exposures. However, the implementation of such policies may inadvertently contribute to an increase in bank common holdings as they attempt to engage in risk-shifting strategies. The findings indicate that asset commonality increases exposure to systemic risk under higher implementation of quantity and financial institution-targeted macroprudential policies. This occurs as banks shift their risks to different asset classes or portfolios, consequently elevating their vulnerability to systemic risk. The third chapter examines the impact of the similarity of banks environmental behavior on systemic risk using a cross-country sample.The findings indicate a U-shaped relationship between the similarity of bank environmental behavior and systemic risk among banks. Our result reveals that the similarity of banks environmental behavior is positively associated with systemic risk under a low environmental policy index. Also, under a low green macroprudential policy, the commonality of banks environmental behavior is associated with higher systemic risk
Petrovskii, Andrei. "Approches pour les corrélateurs à trois points en N = 4 super Yang-Mills." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS233/document.
N=4 SYM theory has been drawing the attention of a lot of physicists during two last decades mainly due to the two aspects: AdS/CFT correspondence and integrability. AdS/CFT correspondence is the first precise realization of the gauge/string duality whose history starts in the 60's, when a string theory was considered as a candidate for describing the strong interactions. In 1997 Maldacena made a proposal about the duality between certain conformal field theories (CFT) and string theories defined on the product of AdS space and some compact manifold, which implies a one to one map between the observables of the gauge and string counterparts. Up to now AdS/CFT correspondence still remains a conjecture. The duality of N=4 SYM and the appropriate string counterpart is the most notable example of the AdS/CFT correspondence. One of the main obstructions to exploring it is the fact that weak coupling regime for the gauge theory is the strong coupling regime for the string theory and vice versa. Therefore as long as perturbative methods are applied, one can not compare the observables of dual counterparts directly apart from some specific cases. At this point the huge symmetry of N=4 SYM plays an important role allowing exact computation of the theory observables at least in the planar limit. This property of the theory is called integrability. The observables of the N=4 SYM are Wilson loops and correlation functions built out of gauge invariant operators. The space-time dependence of the two- and three-point correlators is fixed by the conformal symmetry up to some parameters: dimensions of the operators in the case of two-point functions and dimensions of the operators and structure constants in the case of three-point functions. It's commonly accepted to refer to the problem of finding the dimensions of the operators as the spectral problem. On the classical level the operator dimension is equal to the sum of the dimensions of the fundamental fields out of which the operator is composed. When the interaction is turned on, the conformal dimension gets quantum correction. In order to compute three-point functions, apart from the conformal dimensions of corresponding operators one needs to compute the structure constants. In CFT computation of the higher-point correlators eventually can be reduced to computation of two- and three-point functions by means of the operator product expansion. Therefore two- and three-point functions appear to be building blocks of any correlator of the theory. This thesis is devoted to computation of three-point functions and consists of two parts. In the first part we consider the general approach for computing three-point functions based on the so-called spin vertex, which is inspired from the string field theory. In the second part we consider a specific kind of three-point functions called heavy-heavy-light, which are characterized by the property that the length of one of the operators is much smaller the lengthes of other two. It happens that this kind of correlators can be considered as diagonal form factors which supposes that in this case one can apply the results obtained in the form factor theory
Lajmi, Abdelmajid. "Conception d'un appareil de mesure de tension d'une courroie à trois points de déflexion." Mémoire, École de technologie supérieure, 2002. http://espace.etsmtl.ca/819/1/LAJMI_Abdelmajid.pdf.
Abgrall, Eric. "Caractérisation par l'essai de multifissuration de la fragilité et de l'adhérence de couches minces d'oxydes sur des substrats métalliques : Modélisation des phénomènes." Limoges, 2002. http://www.theses.fr/2002LIMO0012.
A bibliographic study presents the main techniques allowing to determine the mechanical properties of coatings. Among them, the multicracking test, that consists in studying the cracks network appearing in a film submitted to a four-point bending test, has been chosen
Salaun, Armelle. "Etude de l'endommagement en flexion 3 Points et en flambage de domposites carbone / époxy unidirectionnels et bidirectionnels à plis croisés." Caen, 1998. http://www.theses.fr/1998CAEN2009.
Millot, Thierry. "Etude d'un essai original de flexion-torsion 4 points et application à la modélisation du comportement des matériaux composites en contraintes complexes." Besançon, 1990. http://www.theses.fr/1990BESA2051.
Missemer, Ludovic. "Etude du comportement sous très hautes températures des Bétons Fibrés à Ultra Performances : application au BCV." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00680994.
Richard, Andy. "Modèle de satellite à trois couches élastiques : application à la libration en longitude de Titan et Mimas." Observatoire de Paris, 2014. https://hal.science/tel-02095288.
The longitudinal librations of a natural satellite can be defined as the oscillations around its uniform rotation. Their amplitudes depend on the internal structure of the satellite and can be used to probe the interior of these celestial bodies. Recently, the analysis of the Cassini spacecraft observations has suggested the presence of an internal ocean Titan. The measurements of its librational motion could help to characterize the ocean. During the thesis, we modelized the librational motion of a three-layer icy satellite evolving on a non-Keplerian orbit and submitted to an atmospheric torque. The objectives were to determine the influence of the internal structure and the elastic tidal deformations on the longitudinal librations. We determined that the elastic deformations of Titan's layers reduce the orbital frequency libration at the same order as those obtained for a solid model. The signature of the ocean in the libration is thus difficult to delect and require a precision of a few tenth meter on the surface motion to be detacted. The recent observations of Mimas librational motion couldn't be explained by a solid model of the satellite. We showed that the librational motion of Mimas containing an internal ocean match the observed libration amplitude, providing a new scenario in Mimas formation and internal structure
Lalo, Arnaud. "Vieillissement de systèmes multicouchesdestinés aux miroirs de satellites pour l'observation de la terre : Stabilité et endommagement des couches minces d'argent." Grenoble INPG, 2007. http://www.theses.fr/2007INPG0096.
Improving the reliability of devices which are integrated in space vehicles is strongly related to the thermo mechanical stability of the consisting materials. For example, to extend the life period of a satellite mirror, ageing effects as dewetting or interdiffusion in stacks of thin layers must be avoided or delayed. Because the mentioned ageing effects depend not only on the sur-rounding atmosphere but principally on temperature and residual or externally applied stresses, we designed a bending rig to induce compressive or tensile stresses in characteristic stacks of thin layers on substrate systems intended for satellite applications. The bending device was adapted to an atmosphere-controlled furnace. Ageing experiments were conducted under applied stresses ranging form +80 MPa (tensile) to -760 MPa (compressive) and from ambient temperature to 150°C (423K). Additional experiments of deflexion measurements under controlled atmosphere and temperature were designed and conducted. Concurrently, chemical and mechanical char ac¬terizations were performed, including nanoindentation with thin film-specific data processing. The project enabled to discuss the kinetics of the morphological evolution, which occurs in the 100nm reflective Ag layers of the mirror stacks, when submitted to accelerated ageing conditions. Key words: thin films, ageing, reliability, silver-based mirrors, stress, accelerated life test, nanoindentation, four-point bending, diffusion
Hun, Manitou. "Influence de l'eau sur le décollement d'une interface par fléxion d'un bicouche de chaussée urbaine." Ecole centrale de Nantes, 2012. https://tel.archives-ouvertes.fr/tel-00851093.
In order to investigate the mechanisms of debonding of urban roads, this thesis focuses on their characterization in the laboratory. In this work, the idea is to know whether the presence of water (by infiltration into materials) combined with me chanical bending can play a role in the deterioration of the interfaces coupling especially of the cement concrete to the asphalt concrete. A 4 -point bending test allowing to generate interface failure in mixed mode (mode I and II) is chosen a priori and adapted. The mechanical analysis of the test is conducted in plane strain with a Multi-particle elastic Model of Multilayer Materials specifically dedicated to the study of edge effects in multilayer structures under bending, the M4-5n. The problem written analytically and solved in Scilab allows optimizing the geometry of the specimens in order to facilitate the delamination. The testing device is developed in the labo ratory. Bilayer specimens Alu/PVC are used to calibrate the testing device. In order to immerse the specimens in water during the tests, a specific aquarium is constructed. The experimental results demonstrate the effect of temperature on the resistance of the int erface. The techniques of Digital Image Correlation are used to experimentally measure the crack opening and sliding displacement. These techniques are used to determine the stress intensity factors and the energy release rate given by Dundurs. These values are compared successfully with those of M4-5n. In the 20°C water, the experiments show that water privileges the process of debonding
Makni, Amine. "Comportement mécanique et physico-chimique en flexion 4 points et en température des couches d'oxydes formées sur le fer et sur l'acier mi-dur." Compiègne, 2007. http://www.theses.fr/2007COMP1700.
This work is devoted to the problems met during the hot rolling of semi-hard steel sheets. The oxide layers formed during this working process can, indeed, induce various surface defects. These problems s are related to the oxide scale properties. Our contribution thus relates to the follow-up of the mechanical and physicochemical behavior of these oxides developed under wet oxidizing atmospheres. Following a mechanical study carried out using 4 point bending tests, we determined a behavior law of A-iron ; this is a law of perfect viscosity of the Norton type which characterizes the mechanical behavior of pure iron between 500 and 800°C. The elementary analysis of iron oxides shows a physicochemical stability which depends on the oxidation conditions (nature of the atmosphere, temperature and mechanical loading). In fact, the physicochemical stability of these oxides is assured on1y when steel is in the Y-phase; this stability is preserved after an external mechanical loading. This study also highlighted the role of the nature of the cooling atmosphere on the oxygen redistribution within the oxide layers. The influence of humidity is also studied with respect to the mechanical behavior of the steel / oxide system under 4 point bending. The water vapors improves the mechanical characteristics of the oxide scales. After mechanical loading, two damaging mechanisms of the oxides were observed : a transverse cracking or a delamination. The damaging mechanism depends mainly on the temperature during mechanical loading and the nature of the atmosphere
Lesponne, Martine. "Quantification de deux substances odorantes par trois sujets humains et par trois chromatographes en phase gazeuse. Contribution à la mise en évidence des points critiques de la mesure sensorielle." Dijon, 1994. http://www.theses.fr/1994DIJOS032.
Haouam, Abdallah. "Comportement en flexion 4 points à température moyenne (350-550°C) d'alliage base nickel : étude de la fissuration et du rôle de la vapeur d’eau." Compiègne, 2009. http://www.theses.fr/2009COMP1806.
The objective of this thesis is the determination of the behavior law of nickel based alloy Inconel 600 (NC15Fe), which is used in the steam generators of nuclear power plants, subject to intergranular corrosion process. One of the major objectives aimed by this thesis is the knowledge of synergy between oxidation and mechanical loading. The interval of temperature explored during the experimental study coverts the actual conditions for a safe operation of steam generators (350 - 550°C). The various parameters of influence such as the temperature, the atmosphere (vacuum, air, oxygen and water vapor) as well as the surface quality are explored. From the study of the oxidation kinetics, it shows from isothermal oxidation tests under synthetic air, the recorded weight gain and the oxide film thickness Cr2O3 obtained respectively by the thermo gravimetric analysis (ATG) and the spectroscopy with glow discharge (SDL) are very weak in the temperature range (350 - 800°C); showing the very low reactivity of the material in such conditions. As for the influence of the mechanical loading, the results of the 4- point bending tests carried out under secondary vacuum followed by acoustic emission on Inconel 600 samples by means of a specific assembly, revealing the absence of damage. The influence of the oxygen and the water vapor, on the other hand, shows a modification of the behavior of the material characterized by high amplitudes of acoustic signals and attenuated mechanical characteristics, meaning a corrosion attack. Using the results obtained, in-situ, under a controlled atmosphere, a viscoplastic model of behavior of Inconel 600 in 4- point bending, based on Norton’s law is proposed
Hun, Manitou. "Influence de l'eau sur le décollement d'une interface par flexion d'un bicouche de chaussée urbaine." Phd thesis, Ecole centrale de nantes - ECN, 2012. http://tel.archives-ouvertes.fr/tel-00777011.
Archambeau, Grégory. "Etude de la dynamique autour des points de Lagrange." Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00422422.
Staub, Déborah. "Étude du comportement mécanique à rupture des alumines de forte porosité : Application aux supports de catalyseurs d'hydrotraitement des résidus." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0089/document.
In this work, we study the mechanical behaviour of two types of catalysts supports produced by IFPEN and industrially used in residues hydrotreating. Those extruded supports are made of transition γ-alumina with about 70% of porous volume. The first material’s porosity is exclusively composed of mesopores (< 50 nm). The porosity of the second material is composed of both mesopores and macropores (up to 20 µm). Because of the limited knowledge of the stress fields in embedded catalysts supports in use in a reactor, this study aims at precisely and exhaustively describing the mechanical behaviour of those supports under a wide range of stresses, and identifying the possible damage mechanisms. The final objective is to better understand the influence of microstructural parameters on the mechanical properties of the supports in order to propose some leads about how to improve their mechanical strength. First, an adequate mechanical characterization methodology is set. On one hand, the tensile mechanical behaviour of the supports is studied with three-point bending and diametrical crushing tests. On the other hand, their compressive behaviour under various triaxiality rates is characterized in uniaxial and hydrostatic compression, and by spherical micro-indentation. The different damaging mechanisms are identified by imaging techniques such as scanning electronic microscopy and X-ray micro-tomography. Under tensile stresses, the supports exhibit a brittle behaviour and fracture initiates at a critical flaw. Under compressive stresses, a brittle/quasi-plastic transition is observed with increasing the triaxiality rate. The quasi-plasticity is mainly due to the densification of the macroporosity. The second part of the study consists in identifying, for each material, a fracture criterion able to represent every types of behaviour and physical phenomena observed on the same yield surface. This identification is achieved by coupling the spherical indentation tests to a numerical analysis. Fracture criteria involving hydrostatic pressure are well suited to describe the highly dissymmetric mechanical behaviour of the materials in tension and in compression. The last part of this work aims at studying the mechanical behaviour of a stack of supports under œdometric compression in order to produce stress fields more representative of those existing within the supports stacked in a reactor. This test is analysed by X-ray tomography, which allows us to determine/acknowledge the different damaging mechanisms involved in fragments and fines generation. The results illustrate the suitability of the bending and indentation tests to characterize the mechanical properties of a single support and relate them to its mechanical behaviour in a stack of supports under compression
Cayla, Denise. "Errance et points de repère chez Wim Wenders : analyse de trois films : Alice dans les villes, Au fil du temps, l'Etat des choses." Montpellier 3, 1988. http://www.theses.fr/1988MON30038.
Cayla, Denise. "Errance et points de repère chez Wim Wenders analyse de trois films, "Alice dans les villes", "Au fil du temps", "L'Etat des choses /." Lille 3 : ANRT, 1989. http://catalogue.bnf.fr/ark:/12148/cb37612552p.
Picque, Benjamin. "Experimental study and numerical simulation of iron oxide scales mechanical behavior in hot rolling." Paris, ENMP, 2004. http://www.theses.fr/2004ENMP1288.
Hot rolling of steels represents one of the most critical steps to achieve finished products with high surface quality. The increasing productivity added to the rising customer requirements result in more and more severe scheduling rules for the HSM. Strip surface aspect is very important in terms of HSM operation costs and productivity limitation. Among all surface defects, the most crippling comes from the oxide scale formed at the surface of the steel during the hot rolling, at the entry of the finishing mill (last part of the hot strip mill): the secondary scale, mechanical behaviour of which is still poorly known. The secondary scale may fracture under the stresses imposed by the successive rolling passes, and can be embedded in the steel strip surface: this defect is called "rolled-in scale defect". In addition, the extrusion of the subjacent metal inside the oxide cracks induces large local modifications of friction and heat transfer conditions. Consequently, a precise description of oxide scale deformation mechanisms is necessary to better define the boundary conditions in a roll bite and to better understand the initiation mechanisms of rolled-in scale defects. Our scientific objective is then to provide a realistic physical and numerical model to simulate the oxide scale flow in the roll bite and in particular, its damage. After the presentation of the industrial process and the context of this study, the physical and mechanical properties of the oxide scale in the finishing mill are investigated. We introduce the Forge2® finite element software, selected for this study to simulate the oxide scale behaviour in a finishing mill stand. The numerical developments performed to simulate the different kinds of oxide damage are described. Three mechanical tests have been selected to approach the solicitations undergone by the oxide scale at the entry of the roll gap, suspected to be critical for damage: the 4-point hot bending test, the hot tension test and the hot plane strain compression test. A numerical study is performed in parallel. Based on constitutive data obtained from these three mechanical tests, the mechanical description of a rolling stand is sufficient for satisfactory simulation of the industrial process
Caballero, Alma. "La France dans le théâtre de l'Amérique Latine : trois courants d'influence dans des points clefs de la géographie et de la culture de Notre Amérique." Paris 8, 1994. http://www.theses.fr/1994PA080930.
There is an undeniable french prescence in the theater of latin america : it can be appreciated through the writings about indigenous theater, and the tours around the continent made by the most celebrated french masters. This influence is also manifest in some historical motives of the evangelization theater, as well as in the french-writt en plays staged by latin-americans. Through the study of texts, reports and historical testimony, our work intends to seize the traces this exchange left in the formation of the public's taste, the conception of the mise en scene, and in the perspectives of a new creativity
Deloustal-Jorrand, Virginie. "L'implication mathématique : étude épistémologique et didactique. Étude sous trois points de vue : raisonnement déductif, logique formelle, et théorie des ensembles. Construction d'une situation didactique qui problématise l'implication." Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE10213.
THE IMPLICATION IS AN OMNIPRESENT CONCEPT IN MATHEMATICS, CONSTITUTIVE OF PROOFS. HOWEVER, THE IMPLICATION, OFTEN IDENTIFIED WITH THE OBJECT OF NATURAL LOGIC, IS ALMOST NEVER TAUGHT AS A MATHEMATICAL OBJECT. IT APPEARS AS A CLEAR AND EASY OBJECT WHEREAS MANY STUDENTS HAVE DIFFICUL TIES RELATED TO THIS CONCEPT UNTIL THE END OF THE UNIVERSITY. FOR THIS STUDY WE TRIED TO ANSWER THE FOLLOWING QUESTIONS : - WHAT IS THE MATHEMATICAL OBJECT "IMPLICATION" ? - WHAT IS ITS "LIFE" IN FRENCH TEACHING? - HOW CAN WE BUILD A DIDACTICAL SITUATION THAT QUESTION THE IMPLICATION ? TO ANSWER THE FIRST QUESTION, WE PRESENT, IN CHAPTER 1, AN EPISTEMOLOGICAL AND DIDACTICAL ANALYSIS OF THE MATHEMATICAL IMPLICATION FROM THREE POINTS OF VIEW : FORMAL LOGIC, SETS THEORY AND DEDUCTIVE REASONING. TO ANSWER THE SECOND ONE, WE STUDIED. LN CHAPTER 2, THE "LIFE" OF THE IMPLICATION, SEEN FROM THESE THREE POINTS OF VIEW, IN SOME SCHOOLBOOKS FROM HIGH SCHOOL TO UNIVERSITY. IN CHAPTER 3, WE PRESENT OUR FIRST RESUL TS, PARTICULARL Y, WHAT WE CALL THE "CAUSAL-TEMPORAL CONCEPTION" OF THE IMPLICATION. FOLLOWING THESE RESUL TS, WE FORMULA TED OUR THESIS : "IT IS NECESSARY AND SUFFICIENT TO KNOW AND ESTABLISH LINKS BETWEEN THESE THREE POINTS OF VIEW ON THE IMPLICATION FOR A GOOD APPREHENSION AND A CORRECT USE OF IT. " TO SUPPORT OUR THESIS WE BUlL TA DIDACTICAL ENGINEERING, PRESENTED lN THE SECOND PART, WHICH ALLOWS TO QUESTION THE IMPLICATION BY AN "INTERPLAY" BETWEEN THESE THREE POINTS OF VIEW. THIS ENGINEERING SHOWS, PARTICULARLY, THE RELEVANCE OF THE SETS POINT OF VIEW TO STUDY THE IMPLICATION
Picque, Benjamin. "Étude expérimentale et simulation numérique du comportement mécanique des calamines lors du laminage à chaud." Phd thesis, École Nationale Supérieure des Mines de Paris, 2004. http://pastel.archives-ouvertes.fr/pastel-00001360.
Chaperon, Thomas. "Segmentation de nuage de points 3D pour la modélisation automatique d'environnements industriels numérisés." Phd thesis, École Nationale Supérieure des Mines de Paris, 2002. http://tel.archives-ouvertes.fr/tel-00009385.
Dans cette thèse, des algorithmes ont été développés dans ce but. L'attention a en particulier été portée sur la segmentation des lignes de tuyauterie. Les solutions logicielles implémentées dans ce cadre ont été validées par des tests auprès d'utilisateurs experts des outils actuels. Les méthodes développées se caractérisent par l'utilisation au cours de la segmentation de primitives géométriques contraintes, issues de connaissances "métier" (par exemple relations de continuité ou de tangence). L'ajustement de primitive géométrique est un élément de base au sein de ces travaux. Les procédés mis en œuvre, qui utilisent une définition véritablement géométrique des primitives, montrent de bonnes performances en pratique. D'autre part, l'un des problèmes majeurs concerne les moyens de valider le modèle ajusté. La question de la validation de modèle géométrique a été examinée. Nous présentons des méthodes originales construites à partir d'outils statistiques. Enfin, une autre contribution de cette thèse se situe au niveau des algorithmes d'extraction de primitives géométriques d'un nuage de points. Les méthodes présentées ont été appliquées dans le contexte des lignes de tuyauterie, mais semblent également pertinentes pour résoudre la question plus générale de la modélisation totalement automatique d'un environnement numérisé.
Arsenie, Ioana Maria. "Etude et modélisation des renforcements de chaussées à l'aide de grilles en fibre de verre sous sollicitations de fatigue." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00968768.
Zhe, Miao. "Réactivité et propriétés mécaniques des interfaces entre un alliage Al-Si et un renfort Fe ou Ti." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00648832.
Soumahoro, Zoumana. "Etude du couplage thermomécanique dans la propagation dynamique de fissure." Phd thesis, Ecole Polytechnique X, 2005. http://pastel.archives-ouvertes.fr/pastel-00001627.
Autuori, Barbara. "Modélisation par éléments finis de la face humaine en vue de la simulation de sa réponse au choc." Phd thesis, INSA de Lyon, 2004. http://tel.archives-ouvertes.fr/tel-00008231.
En vue de prédire précisément les risques de blessures de la face et du contenu intracrânien, l'objectif de cette thèse est de développer un modèle en éléments finis de la structure osseuse de la face et du crâne pour la simulation de sa réponse au choc.
Une première partie du travail a consisté à construire le maillage d'une structure osseuse cranio-faciale à partir de coupes scanner de tête. Le choix d'un maillage en éléments de type plaque, de densité suffisante pour représenter fidèlement la géométrie complexe de cette structure osseuse et d'épaisseur variable, a été fait.
L'hypothèse d'un matériau osseux homogène et isotrope a été choisie pour l'ensemble de la structure cranio-faciale. Des essais de flexion statique sur des échantillons d'os crânien, associés à leur simulation numé-rique et une méthode d'identification, ont permis de définir les propriétés élasto-plastiques de ce matériau. Les résultats se situent correctement par rapport aux intervalles de valeurs de la littérature.
La réponse du modèle cranio-facial a été validée sous sollicita-tions statiques. Pour cela des essais spécifiques de compression de la face ont été réalisés sur pièce anatomique. Les courbes globales effort - déplacement expérimentale et numérique ont été comparées pour « calibrer » les propriétés du matériau. La réponse du modèle a ensuite été validée par comparaison du champ de déplacement mesuré expérimentalement par une méthode de corrélation d'images et obtenu par simulation.
Le modèle ainsi validé en statique a été évalué sous sollicitations dynamiques. Sa réponse au choc a été comparée aux résultats d'un impact sur la face réalisé spécifiquement. La réponse au choc globale du modèle est similaire à celle enregistrée expérimentalement.
Plusieurs perspectives d'exploitation de ce modèle sont envisa-geables dans le domaine du choc ou celui de la chirurgie. En particulier, il aidera à définir des critères de blessures de la tête en cas de choc sur la face.
MONTESINOS, ANGEL JOSE. "Trois essais de geometrie riemannienne : sur les varietes a flot geodesique topologiquement transitif. sur la conjugaison des flots geodesiques des surfaces sans points conjugues. sur la caracteristique d'euler des varietes d'einstein de dimension six." Paris 6, 1990. http://www.theses.fr/1990PA066248.
Jarossay, David. "Multizêtas p-adiques et multizêtas finis." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC208.
This thesis concerns the pro-unipotent fundamental group of the projective line minus three points, defined by Deligne in 1989. We consider more specifically its cristalline Frobenius and its "Knizhnik-Zamolodchikov" connection. The goal is to understand its p-adic periods, that is to say the p-adic analogues of multiple zeta values. The study also leads to a notion of "finite multiple zeta values" ; it enlightens another notion of finite multiple zeta values defined by Zagier in 2011. The parts I and II concern p-adic multiple zeta values. We give several ways, one "direct" (part I) and two "indirect" (part II), to compute them. It enables to discover as well certain properties of multiple harmonic sums. The part II leads to, among other things, the definition of the notion of finite multiple zeta values evoked above. These are elements of the product of all Zp's ; they can be expressed in terms of p-adic multiple zeta values, and vice versa. They must be seen as a substitute to p-adic multiple zeta values, which have the advantage to be given by very simple explicit formulas, and whose properties reflect those of p-adic multiple zeta values. The part III is mostly a study of the algebraic properties of finite multiple zeta values, and of other related numbers. We justify the statement that they are variants of multiple zeta values, by showing that they satisfy variants of the standard algebraic properties of multiple zeta values. At the end of part III, we obtain a new series expansion of p-adic zeta values. The three parts also contain other annex results
Gharib, Turath. "Renforcement des structures historiques en maçonnerie par matériaux composites : application aux murs en pierres calcaires." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10094/document.
This work concerns the study of the reinforcement of stone structures with composite materials. Two reinforcing techniques are used. One is reinforcement by cement matrix reinforced with textile TRC of glass fiber. The other is by reinforcing FRP fiberglass rods according to NSM technique (near-surface mounted). The first phase consists of materials characterization and analysis of mechanical behavior in compression shear and tensile of small masonry specimens made of stone and mortar. The characteristic values of the mechanical behavior of the masonry are compared with the different models in the literature which calculate the characteristic parameters and give a good approximation with the experimental results. In addition, the behavior of reinforced materials is tested in tension and the behavior of the adhesion between the reinforcement and the masonry is studied. The second phase focuses on strengthening masonry walls subjected to two types of loading. One is in-plane shear of walls made with the diagonal compression test. Represents the second bending loads to 3 points out of plane walls accompanied by axial compression forces which cause a compressive stress of 0.2 MPa. The shear test was performed on square walls of five rows of stones with mortar. Strengthening by two vertical bars NSM FRP significantly improves the ductility and shear modulus of the walls and the reinforcement with two orthogonal layers TRC improves shear strength. Finally the application of analytical models used to compare the experimental results with the results given by the models. In addition, the bending test with 3-point is carried out on walls composed of twelve rows of stones with mortar. The reinforcement with two vertical bars and two crossbars increased more elastic stiffness. However, the reinforcement with TRC composed of a single layer of textile accompanied with a vertical bar FRP does not increase the resistance of the wall relative to the resistance of the reinforced wall with a single layer of textile or with a simple vertical bar
Leite, Pinto Rodrigo. "Caractérisation physique et thermo-mécanique et analyse de fiabilité des fibres optiques à base de silice." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S125.
Optical fibers are being increasingly used today by internet providers in networks dedicated to telecommunications. By being low-cost, low attenuation and by providing an excellent quality of optical signal, optical fibers are quickly becoming the number one choice in data networks worldwide. Once installed in ducts or alongside power-lines, optical fibers might easily be subjected to thermal, mechanical or chemical strains that can damage their structural integrity and lower their reliability. This PhD is part of an academic-industrial cooperative project and is focused on studying the behavior of silica-based optical fibers once installed in networks, and defining an method for calculating their lifetime. Static fatigue test have been made in various environments. We thus analyzed the behavior of our optical fibers once subjected to distilled water heated at different temperatures, to environments where temperature and humidity were varied, and to plain air. We also looked into the corrosion parameter alongside the defects distribution in our fibers by dynamic fatigue testing using a two-point bending and a short-length tensile testing bench. Our results allowed us to study the reliability of our fibers using two theoretical models available in the literature: Mitsunaga’s reliability model and Arrhenius’ crack-growth model
Le, Ber Simon. "Matrices nanostructurées obtenues par voies liquides : application aux composites à matrice céramique." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14323/document.
A new CMC manufacturing process has been developped ; the active filler technique is used in order to obtain a low cost composite. Active fillers must react under nitrogen atmosphere at a temperature below 1100°C so that the Nicalon fiber reinforcement is not damaged. Two active fillers meeting these criteria and offering an interesting volume expansion have been identified : AlB2 et TiSi2.The planetary milling of these fillers has been explored in order to assess the influence of microstructure refinement on properties. Powders with high specific surface areas and of granulometry close to the nanometric scale were obtained. The nitridation of the active fillers was examined and a size effect on TiSi2 reactivity was displayed.Milled powders were used in colloidal suspensions in order to be impregnated in preforms. Samples were subsequently nitrided at 1100°C ; this step was crucial for matrix cohesion. A PIP cycle was eventually performed in order to reduce residual porosity.The oxydation behaviour of materials was studied in conditions corresponding to the considered aeronautics application. Mechanical properties of composites were estimated by 3 point bending tests. Combining the use of TiSi2 and of a polysiloxane enabled to obtain a composite whose maximum bending stress was remarkable considering the limited number of steps required for its processing
Sauvage, Jean-Baptiste. "Caractérisation et modélisation de l’adhérence dans les assemblages collés." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH9553/document.
This thesis deals with the development of a mechanical test for the characterization of the practical adhesion of an adhesive to a substrate. The aim is to study the different methods of characterization of the adhesive strength in bonded joints and to model the associated behaviour. The first part of the thesis consists of a bibliographic study of the mechanical tests to characterize this adhesive strength. These tests are classified by distinguishing them in propagation or in initiation of rupture. This state of the art demonstrates the advantage of using the 3-point bending and the butt joint tests for this study. The second part of the thesis presents the different materials and the various surface treatments used to vary the adhesion of adhesives to the substrate. The third part presents the core of this thesis work which is the 3-point bending test. The study shows that this 3-point bending test leads systematically to initiate a localizable adhesive rupture on the surface of the substrate, at least for the adhesives used in our study. An energy approach of the test allows to determine an adhesion criterion independent of the physical parameters of the materials and dimensions of the specimen. On the other hand, it has been shown that the thinner the substrate, the more precise the results of the adhesive strength. Finally, a fourth part is devoted to numerical modelling by the finite element method. The results obtained show that opening constraint in mode I is that which controls the rupture. In conclusion, the 3-point bending test clearly allows to measure the energy of the adhesive rupture initiation
Arsenie, Ioana maria. "Etude et modélisation des renforcements de chaussées à l'aide de grilles en fibre de verre sous sollicitations de fatigue." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAD025/document.
The objective of the PhD thesis « Study and modelling of the pavement reinforcement with glass fibre grid under fatigue loading » is to characterize the reinforcement role of the asphalt surface layer of a pavement subjected to fatigue loading with the glass fibre grid or « geo-grid ». The fatigue behaviour of the composite formed of asphalt mixture and geo-grid is studied in laboratory with four point bending tests (4PB) performed with sinusoidal waveform, at 10°C and 25 Hz. The tested specimens are 630 x 100 x 100 mm3 beams of two types: asphalt beams (non-reinforced) and asphalt beams reinforced with geo-grid (reinforced). A four point bending prototype device was designed to perform the fatigue tests on the big size asphalt specimens. The device respects the European Standards. The experimental results were used for modelling of the damage evolution under fatigue loading of the both types of beams. The damage laws of the materials are Bodin laws programmed in Cast3M finite element code. Two categories of models were conceived, respectively: one layer beam models and tri-layers beam models. Each category has a model of non-reinforced beam and a model of reinforced beam. Furthermore, Castro-Sanchez model was used to predict damage evolution and in particular the number of cycles to failure correspondent to the two types of beams
Raid, Idir. "Développement de méthodes numériques et de caractérisations expérimentales pour l’étude des contraintes mécaniques et défaillances induites dans les dispositifs microélectroniques avancés." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI084.
The trend in the microelectronics industry is towards miniaturisation, from transistors to the integrated circuit package. This constant desire of compactness is certainly motivated by economic reasons, but also by the perspectives to gain in performance, power and ergonomics. In early 90s, 0.8 µm was the transistors gate length at major semiconductor manufacturers. The length has been reduced to 6 nm with a density of integration of 125 million transistors per square millimetre. However, such a transition does not come without consequences, as far as it concerns fracture mechanisms, it is particularly true regarding the low-k dielectrics. This family of materials, although porous and fragile, is essential to ensure the insulation in the circuitry of an increasingly dense Back-End of Line (BEoL), with increasingly fine lithography. Besides, due to its porosity, it also has a hydrophilic behaviour which greatly reduces both its insulation quality and stress strength. For all these reasons, the seal ring, the copper interconnection structure that encircles the chip, was implemented to (i) ensure the mechanical integrity of its interior, containing the electrically active part of the die, and (ii) to protect it from moisture and other chemicals intrusions. Hence the interest of this work to address the thermomechanical stresses and cracking phenomena which are articulated around the BEoL. To do so, various paths revolving around the same line of research, mechanical integrity in microelectronics systems, are proposed. (i) Two ways of evaluating stress fields in active silicon and passive BEoL are investigated: by implementing sensor structures based on the principles of piezoresistance and extensometry respectively. (ii) The Four-Point Bending technique is benchmarked, and readapted to account for the crack length, for cracks advancing is homogeneous (decohesion) and heterogeneous (debonding) thin films structures. (iii) A Finite Elements approach, combined with Cohesive Zone Models under Small-Scale Yielding conditions, is proposed to analyse the influence of the arrangement and plasticity of copper in the interconnections in the resistance to crack advance
Jiang, Yunfeng. "Three-point functions in N=4 Super-Yang-Mills theory from integrability." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066395.
This thesis is devoted to the study of three-point functions of N=4 Super-Yang-Mills (SYM) theory in the planar limit by using integrability. N=4 SYM theory is conformal invariant at quantum level and is believed to be completely solvable. By the AdS/CFT correspondence, it is dual to the type IIB superstring theory on the curved background AdS5×S5. The three-point functions are important quantities which contain essential dynamic information of the theory.The necessary tools in integrability and the existing methods of computing three-point functions are reviewed. We compute the three-point functions in the higher rank SU(3) sector and obtain a determinant representation for one special configuration, which allows us to take the semi-classical limit. By exploring the relation between long-range interacting spin chain and inhomogeneous XXX spin chain, we develop a new approach to compute three-point functions in the SU(2) sector at one-loop and obtain a compact result. In the Frolov-Tseytlin limit, this result matches the result at strong coupling.We also explore new formulations of the three-point functions. In one formulation inspired by the light-cone string field theory, we constructed the spin vertex, which is the weak coupling counterpart of the string vertex for all sectors at tree level. Another formulation which is related to the form factor boostrap program in integrable field theory is reviewed. At weak coupling, we study the finite volume dependence of a special type of three-point functions which are related to the diagonal form factors
Belmehdi, Yassine. "CONTRIBUTION A L'IDENTIFICATION DE NOUVEAUX INDICATEURS DE DEFAILLANCE DES MODULES DE PUISSANCE A IGBT." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00988332.