Dissertationen zum Thema „Coefficient de comportement“
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Le, Thi Hong Hanh. „Distribution et comportement du polonium dans deux anciens sites miniers français“. Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4028.
Der volle Inhalt der QuellePolonium-210 (210Po) is a naturally occurring radionuclide resulting from the decay of uranium-238. In addition to its natural presence, anthropogenic activities can lead to a local increase in the concentration of 210Po, in particular uranium mining. The aim of this study is to better understand the impact of human activities on the distribution and behaviour of 210Po in soils. To this end, two former French mining sites are examined. The first, called "Rophin", located in the Puy-de-Dôme region, was mined in the middle of the 20th century. The second one, not exploited, is located on the site called "les Granges du colonel" in the Mercantour National Park in the Alpes-Maritimes. This second site has never been exploited, but it was listed as a potential site in the 1960s. Soil samples were taken from the wetlands of both sites. The total 210Po activity in each sample was measured. The sequential extraction method was then applied to determine the geochemical distribution of 210Po in the soils studied. Most of the 210Po (more than 70%) is present in the residual fraction, soluble only in concentrated acids (HF, HNO3). This suggests low lability of polonium in the environment. Apart from the residual fraction, 210Po is mainly present in the carbonate-related fraction at pH 5. The impact of pH and bicarbonate content on the solid-liquid distribution coefficient of 210Po was also studied. The results showed that mining activities at Rophin promoted the exhalation of 222Rn and led to disequilibrium between 210Po and 238U
Idir, Achour. „Justification du coefficient de comportement sismique des structures en béton armé par des approches statiques équivalentes“. Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0508.
Der volle Inhalt der QuelleAbdul, Baki Ali. „Analyse probabiliste du comportement de deux remblais sur versant instable“. Lyon, INSA, 1992. http://www.theses.fr/1992ISAL0049.
Der volle Inhalt der QuelleThe present work consists of a probabilistic analysis of two behaviour of two embankments A and B built on the moving s lop of the experimental site of Sallèdes. After a bibliographical analysis, this work contains two parts: - The first part suggests: gathering of all the boreholes made on t he site and the stocking or the data relating to them, statistical parameters (average, standard deviation, variance, variation coefficient, etc. ) of each of those properties and the signification levels of the normal and beta laws for the distribution of each variable as well as their logarithm and their inverse, study of the correlation between every two parameters beneath each embankment and on the whole site, along with the correlation between those parameters and the three axis x, y and z, study of the horizontal and vertical autocorrelation of the different proprieties. - The second part proposes : reviewal of the deterministic methods of stability calculation necessary to the development of the blocks methods and comparison of the results obtained by that method with those obtained by t he program "PETAL" concerning stability calculation, introduction of probabilistic analysis techniques into the stability calculation of the blocks method using the numerical integration methods, analysis or the stability of two embankments A and B using the probabilistic calculation program. Comparison of results with those obtained from deterministic calculations
Ait, Ali Yahia Lyes. „Etude expérimentale de l’influence de la morphologie des agrégats de suies sur leur comportement thermophorétique“. Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1081.
Der volle Inhalt der QuelleThe main objective of this study is to improve the knowledge about the morphological influence of fractal aggregates on their thermophoretic behavior. For this purpose, an original tri thermal device aimed to capture this kind of particles by thermophoresis deposition was developed. This device is composed of three concentric tubes where particles flows through an annular space between the inner and outer tubes with imposed temperatures, the inner one is cooled and the outer is heated. Particles will deposit by thermophoresis on the cold wall of the inner tube. This device is based on the so called penetration method, where the deposition rate on a cold wall is obtained by particles concentrations measurements upstream and downstream of the test section. A deposition model developed in this study allowed us to determine the thermophoretic diffusion coefficient Kth. We validated the tri thermal device using monodispersed spherical latex particles and also mono and polydispersed spherical oil particles distributions. Indeed, a good agreement was found between our experimental determination of the thermophoretic diffusion coefficient and the theoretical values of Beresnev and Chernyak and also experimental results of the litterature. We finally conducted a study where we applied the device with soot aggregates that have variable morphology and physicochemical nature. This study confirmed the results presented by Mackowski and Brugière about the increase of the aggregates thermophoretic diffusion coefficients Kth with the primary particle number and therefore with the electrical mobility diameter. A confrontation between the coefficients Kth of the different types of aggregates allowed us to find an influence of the primary particles diameter, the fractal dimension Df and also the ratio EC/TC on the thermophoretic behavior of soot aggregates
Sandid, Mohamed Habib. „Contribution à l'étude des aéroréfrigérants : comportement des tubes à ailettes à haute température“. Valenciennes, 1987. https://ged.uphf.fr/nuxeo/site/esupversions/25a3d1c4-6ca4-4edb-b0f4-1e509e6f0c38.
Der volle Inhalt der QuelleBouchoucha, Ali. „Étude du comportement en frottement et usure des contacts électriques glissants cuivre-acier et cuivre-graphite“. Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL006N.
Der volle Inhalt der QuelleCanet, Valentine. „Étude du comportement et de la stabilité des rideaux de soutènement“. Châtenay-Malabry, Ecole centrale de Paris, 1985. http://www.theses.fr/1985ECAP0016.
Der volle Inhalt der QuelleBelmokhtar, Malik. „Contributions à l'étude du comportement thermo-hydro-mécanique de l'argilite du Callovo-Oxfordien (France) et de l'argile à Opalinus (Suisse)“. Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1026/document.
Der volle Inhalt der QuelleDeep low permeability claystones (10-20 m2), such as Callovo-Oxfordian claystone (COx) in France or the Opalinus Clay in Switzerland, are potential host rocks for deep geological radioactive waste disposal. During the various phases of the storage, these rocks will be subjected to thermo-hydro-mechanical (THM) coupled effects. The determination of their THM parameters remains to be completed for a better understanding of the near-field response of the storage galleries.The experimental study of low permeability geomaterials is difficult and several questions about their THM behavior still remain. In this context, two original experimental systems with high precision local strain measurements and reduced drainage lengths (H) were developed and used for saturated drained tests: an isotropic compression cell (H = 10 mm) and a standard triaxial cell with a reduced drainage length using a geotextile placed around the sample (H = 19 mm).A detailed poroelastic characterization of the COx argillite in the isotropic cell provided a set of compatible transverse isotropic poroelastic parameters of the material, identified in a theoretical framework allowing to determine the Biot tensor components (coefficients b1 and b2, perpendicular and parallel to bedding plans, respectively). A key parameter not well documented to date is the unjacketed modulus that was determined by means of an unjacketed compression test (Ks = 21.7 GPa).A temperature control and an accurate calibration of thermal parasite effects allowed the investigation of the thermal volumetric response of the COx argillite during a drainage test under constant isotropic confining stress close in-situ state conditions. A thermoelastic expansion followed by a thermoplastic contraction was observed, with a transition at a temperature of 48 °C, close to the highest temperature supported during the geological history of the claystone. It is thus confirmed that such claystones keep in memory the maximum supported geological temperature. The precision of the deformation measurements also made it possible to identify a volumetric creep that is enhanced at 80 °C.Poroelastic calculations with the boundary conditions of the improved drainage system allowed to determine the magnitude of axial strain rates allowing good drainage during triaxial drained shearing (6.6×10-8 s-1). The drained tests carried out on the COx claystone showed a good compatibility with a criterion already published. Coherent data were also obtained on the Opalinus Clay failure criterion, that were compared to those of uniaxial compression tests at different speeds on samples equilibrated at 94% relative humidity, that exhibited a dependence of the peak strength on the shear rate.These results make it possible to reduce the uncertainties concerning the THM properties of claystones and should allow a better estimation of the response of the near field close to the galleries during the different phases of their service period.Key words: claystone, permeability, drainage, saturation, poroelasticity, Biot coefficient, transverse isotropy, triaxial testing, heating, creep
Ba, Adji Cathy. „Étude du comportement tribologique d'un couple de matériaux ferromagnétique acier XC48 en contact mécanique et magnétique à sec“. Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2318/document.
Der volle Inhalt der QuelleThis thesis is about the study of the tribological behavior of a couple of ferromagnetic materials XC48 steel in mechanical and magnetic dry contact. It consists in identifying the generated effects of the presence or absence of a magnetic field at the static and sliding contact interface. The first step was to establish constraint equations which govern the linear, punctual and surface response of the solids under given loadings, by using models developed in the theory of elasticity. They were then simulated under Mathematica to obtain analytical results of stress fields in sub-surfaces. In the second phase, the dry contact tests carried out by means of a standard pin-on-disc tribometer reveal an increase in the coefficient of friction with the magnetic field on the tribological contact. The analysis by X-ray diffraction shows that the wear debris during the tests with magnetic field comprises the presence of iron oxide. The characterization by scanning electron microscopy and profilometry of worn material shows the state of the sub-surface with modification of the grain structure and presence of soft wear from testing with magnetic field. The photoelasticity measurements show the influence of the magnetic field on the stress fields. By varying the kinematic parameters of the test on our numerical model, we observe an increase in stress fields. These mechanical, magnetic and physicochemical parameters are complex and the study contributes to understanding these problems of dry friction
Pavier, Edith. „Caractérisation du comportement d'une poudre de fer pour le procédé de compression en matrice“. Grenoble INPG, 1998. http://www.theses.fr/1998INPG0042.
Der volle Inhalt der QuelleAdam, Olivier. „Etude expérimentale du comportement des gouttes en régime d'interaction“. Toulouse, ENSAE, 1997. http://www.theses.fr/1997ESAE0015.
Der volle Inhalt der QuelleBoutonnier, Luc. „Comportement hydromécanique des sols fins proches de la saturation. Cas des ouvrages en terre : coefficient B, déformations instantanées et différées, retrait/gonflement“. Grenoble INPG, 2007. http://www.theses.fr/2007INPG0108.
Der volle Inhalt der QuelleUnsaturated soils have been widety investigated since 1990. But few researches have focused on the transition between saturated and unsaturated states. A detailed analysis of the link between soil behaviour and degree of saturation has been carried out and an hydromecanical model has been built for fine soilnear saturation (occluded air bubbles). The original assumption in this modeI is to consider that air is advected by water. The modet has been used successfully to forecast the pore pressure in soft: soil under CUbzac-les-Pont test embankment D and the pore pressure construction in dams. Finally, a new methodology is presented to calQllate the modeI parameters from standard oedometric test. The versatility of the model is iIIustrated by simulating instantaneous settlernent, detayed settlement, swetling and shrinking cydes
Ramos, Da Silva Mikaël. „Etude théorique et expérimentale du comportement poromécanique des roches non saturées“. Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210116.
Der volle Inhalt der QuelleCette étude expérimentale se propose donc de contribuer à une meilleure compréhension du comportement hydromécanique de matériaux rocheux partiellement saturés. Pour ce faire, la démarche suivie a consisté à se baser sur des techniques et outils bien établis pour les sols (meubles), et à les adapter aux matériaux rocheux. Dans ce contexte, une première étude a été menée sur un matériau rocheux argileux, le schiste de Beringen, et a permis d’évaluer l’influence de la succion pour les états de compression simple.
Suite à cette première étude, d’autres états de contrainte ont été envisagés, principalement au moyen de l’essai triaxial. Le contrôle de la succion en cours d’essai a demandé d’importantes transformations au système triaxial déjà disponible au laboratoire. En parallèle, un nouvel équipement, comprenant notamment un contrôle de la succion par la méthode de translation d’axes, a été conçu et mis en service. La suite du programme expérimental a été réalisée sur une roche poreuse et très homogène :le calcaire de Sorcy.
A l’état sec, les résultats d’essais triaxiaux et polyaxiaux ont permis la construction de surfaces de charge tridimensionnelles. En plan méridien, comme pour d’autres roches poreuses, la résistance augmente avec la pression de confinement lorsque celle-ci reste assez faible (inférieure à 15 MPa environ) ;le comportement est fragile. Aux confinements plus élevés, le comportement devient ductile. En plan octaédrique, la forme de la surface évolue depuis le triangle jusqu’au cercle dans la partie fragile, puis continue à évoluer vers un triangle (inversé par rapport au premier) dans le domaine ductile.
En conditions saturées, un ensemble cohérent de paramètres poroélastiques a été mesuré, parmi lesquels le coefficient de Biot (qui a été évalué à environ 0.85). La variabilité de ces paramètres entre échantillons et en fonction de l’état de contrainte a été examinée. Dans le domaine poroplastique, c’est la contrainte effective de Terzaghi qui se révèle contrôler le comportement mécanique, malgré que le coefficient de Biot soit inférieur à 1. En plan méridien, l’enveloppe obtenue pour le matériau saturé se rapproche de celle du matériau sec, moyennant une normalisation par rapport à sa longueur horizontale. Ceci suggère que la prise en compte des conditions non saturées pourrait se faire, comme souvent pour les sols, par l’ajout d’un axe supplémentaire :la succion.
En conditions non saturées, les essais réalisés en conditions isotropes à succion contrôlée montrent une forte augmentation du module d’incompressibilité drainé avec la pression de confinement et une faible augmentation avec la succion. Ceci tend à conforter les hypothèses adoptées.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Di, Giandomenico Maria Vita. „Comportement chimique du protactinium au degré d’oxydation V en présence d’ions sulfate“. Paris 11, 2007. http://www.theses.fr/2007PA112182.
Der volle Inhalt der QuelleBecause of protactinium tendency to polymerisation, hydrolysis and sorption on all solid supports, the equilibria constants relative to monomer species were determined at tracer scale (ca 10-12 M) with 233 isotope. The complexation constants of protactinium (V) and sulphate ions were calculated starting from a systematic study of the apparent distribution coefficient D in the aqueous system thenoyltrifluoracetone/toluene/sodium sulphate/perchloric acid//sodium perchlorate and as function of ionic strength, temperature, free sulphate, protons and chelatant concentration. Parallely, the structural study of protactinium(V) was performed using 231 isotope. XANES and EXAFS spectra show unambiguously the absence of the trans dioxo bond that characterizes the other early actinide elements like uranium and neptunium. In concentrated sulphuric acid (12 and 4 M), protactinium(V) is proved to exhibit a single oxo bond. In 0,5 M and 0,05 M HF medium, the results indicate the absence of any oxo bond: protactinium(V) exists in the form of a pure fluoro-complex
Pan, Linzhu. „Comportement mécanique et thermomagnétique des métaux : fer - nickel - cuivre et bronze en frottement et usure“. Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL045N.
Der volle Inhalt der QuelleKowandy, Christelle. „Comportement tribologique de la fonte grise lamellaire 250 contre les polytétrafluoroéthylènes : Rôle des particules d'usure“. Compiègne, 2007. http://www.theses.fr/2007COMP1668.
Der volle Inhalt der QuelleThe compressors used for the blowing of the plastic bottles generally consist of a cylinder, a piston and segments which must ensure at the same time the sealing between the parts and the lubrication. The segments must be in materials known as "self-lubricating" such as polytetrafluoroethylene. However, during the contact, wear partic1es can be generated. Their morphology is an indicator of the wear process. Mechanical tests of friction were carried out with an alternate tribometer in a plane contact configuration. The materials tested were polytetrafluoroethylenes, pure or reinforced against lamellate grey cast iron. After the characterization of materials, the morphological partic1e attributes are determined by image analysis technique. Wear mechanisms are proposed and correlations between the characteristics of the wear particles, the wear rates and the tribosystem are obtained thanks to the data mining
Velkov, Pance. „Étude de l'approche par le coefficient de comportement de la réponse sismique des murs des bâtiments et des piles de ponts en béton armé“. Châtenay-Malabry, Ecole centrale de Paris, 1996. http://www.theses.fr/1996ECAP0460.
Der volle Inhalt der QuelleLe, Kouby Alain. „Etude du comportement mécanique de micropieux sous chargements monotones et cycliques verticaux : application aux effets de groupe“. Phd thesis, Ecole des Ponts ParisTech, 2003. http://tel.archives-ouvertes.fr/tel-00005722.
Der volle Inhalt der QuelleDans le cas monotone, leffet de groupe est étudié à partir du comportement dune inclusion générique au sein dun groupe en interaction avec des inclusions adjacentes. Les résultats montrent un effet de groupe positif sur le frottement latéral et négatif sur la résistance en pointe. Dans le cas des chargements cycliques, deux cas sont considérés à savoir les chargements à force contrôlée destinés à établir des diagrammes de stabilité cyclique et les chargements à déplacement contrôlé pour les mécanismes de dégradation. Pour les premiers, laugmentation du nombre dinclusions montre un effet positif et pour les seconds, les résultats montrent un effet de groupe positif sur le frottement latéral et négatif sur la pointe.
Xi, Chen. „Etude expérimentale du comportement poromécanique des argilites du COx : influences de l’anisotropie initiale et du chemin de chargement“. Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1I071.
Der volle Inhalt der QuelleThe Callovo-Oxfordian (COx) claystone has been selected as a potential host rock for underground radioactive waste repository in France. The present thesis is devoted to experimental investigation of the poro-mechanical behavior of COx claystone. The emphasis is put on the study of influences of structural anisotropy and loading path. Both instantaneous and time dependent behaviors are considered. For this purpose, a series of laboratory investigations including axial extension creep tests with different loading orientations, shear creep tests on fractured samples with gas permeability evolution measurement, tests for determination of Biot’s and Skempton’s coefficients, lateral decompression and axial extension tests with poroplastic cycles and oedometric tests under different drainage conditions. From the results obtained, it is found that the poromechanical behavior of COx claystone is strongly affected by structural anisotropy, loading path and water saturation degree. The time-dependent deformation is also an important property of the COx claystone. The gas permeability evolution of fractured samples is influenced by various factors including confining pressure and self-sealing ability of clayey rock
Al, Bahri Mohamad. „Influence de la température sur le comportement statique et dynamique des capteurs de pression capacitifs au silicium“. Toulouse, INSA, 2005. http://www.theses.fr/2005ISAT0006.
Der volle Inhalt der QuelleThis memory treats of the study of the thermal behavior of silicon capacitive pressure sensors manufactured based on silicon/glass technology. Their static and dynamic behavior is studied for various designs. In the first chapter, the theory models are developed for sensors with circular diaphragm. In static mode, the models (pressure and tension sensitivities) are clarified in the linear field. In dynamic mode, the dependence of resonance frequency is studied with respect to the pressure and the applied tension. The thermal coefficient has been calculated for all the set of models. The second chapter describes the geometry of the sensor under study, the used technology as well as the test platform. The characterization of the static behavior with respect to the temperature is studied in the third chapter. It has been found that the thermal coefficient of the capacitance at rest is almost constant and independent of the bonded area width. On the other hand, this thermal coefficient is dependent on the diaphragm thickness, the fixed metal plate thickness and the embedding form. The thermal coefficient of the tension sensitivity and the pressure sensitivity varies in quasi-linear manner between -20°C and 150°C. The characterization of the dynamic behavior with respect to the temperature is studied in the fourth chapter. We have found that the thermal coefficient of the resonance frequency varies linearly between -20°C and 150°C. It appeared that the width of bonded area as the thickness of the fixed metal plate does not influence the thermal coefficient of the resonance frequency. This latter depends much more on the thickness of the diaphragm than on the embedding form, which the influence is minor. A comparison between the two models of the thermal coefficient of pressure sensitivity was carried out on a large number of sensors. It validates these two models and demonstrates that the pressure sensitivity depends on the resonance frequency
Ait, Arkoub Idir. „Comportement électrochimique d'électrodes à pâte de carbone activées puis modifiées par adsorption de fibrinogène et caractérisation d'ultramicroélectrodes de fibre de carbone“. Paris 6, 1997. http://www.theses.fr/1997PA066196.
Der volle Inhalt der QuellePelletant, Aurelien. „Elaboration de matériaux composites céramiques à faible coefficient de dilatation thermique pour des applications spatiales“. Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0018.
Der volle Inhalt der QuelleHigh resolution satellite imagery from space optical systems is mainly limited by the mirror size and the mass of structures supporting the mirror. Nowadays, the development of light athermal systems is the major challenge to improve these optical systems. So, light materials having good mechanical properties (E/ρ3 > 10, σf > 100 MPa) and thermal stability (< 2.0e-6/K) are required. Within this context, our project consists in processing new ceramic composites by combining positive thermal expansion coefficient (TEC) materials having good mechanical properties (alumina or ceria doped zirconia) and negative TEC materials (zirconium tungstate or β-eucryptite) The processing of zirconium tungstate-based materials showed several decomposition and chemical reactions with some oxide matrix leading to its giving up. In the case of β-eucryptite, vermicular phenomenon occurs during sintering leading to the formation of intragranular porosity. Sintering parameters optimization can limit this porosity. The study of the thermal behavior of pure β-eucryptite materials shows that the very negative TEC results from microcracking, generated by the TEC anisotropy of its crystal lattice. This microcracking depends on the grain size and the aggregate size in the case of powder materials. Despite the fact that the TEC of its lattice (called intrinsic TE C equals to -0.4e-6/K) is very low, its bulk (or extrinsic) TEC can reach values until -10.9e-6/K according to the processing conditions. In this work, two strategies for developing composites were studied. The first one consists in decreasing the matrix TEC using an uncracked β-eucryptite powder (-0.4e-6/K) while the second one consists in elaborating near zero TEC materials from a microcracked β-eucryptite powder (-3.0e-6/K). When ceria-doped zirconia is used, ceria content must be adjusted in order to limit zirconia phase transformation. This transformation is driven by tensile stresses induced by the β-eucryptite and modifies the composite thermal behavior linearity. In both studied cases, dense composites show a modification of the β-eucryptite intrinsic TEC from -0.4e-6/K to more than +3.2e-6/K as a consequence of compressive stresses applied by the oxide matrix. An uncompleted densification of composites is required to relax these stresses. Taking into account these observations, several very low TEC composites were elaborated. However, the uncompleted densification of composites and the β-eucryptite microcracking greatly decrease the mechanical properties of these materials
AL, BAHRI Mohamad. „Influence de la température sur le comportement statique et dynamique des capteurs de pression capacitifs au silicium“. Phd thesis, INSA de Toulouse, 2005. http://tel.archives-ouvertes.fr/tel-00009524.
Der volle Inhalt der QuelleRousseau, Baptiste. „Interfaces fragiles des ouvrages hydrauliques : morphologie et comportement mécanique“. Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14023/document.
Der volle Inhalt der QuelleIn Quebec, the concrete dams over fifty years are systematically studied since the Saguenay earthquake (1988, 6.2 on the Richter scale) because they were not sized for such hazards. For calculation of the reliability codes for Hydro-Quebec structures, different parameters on the morphology of structure and the physical and mechanical parameters are needed. Among these, the shear strength of interfaces (concrete-concrete, concrete-rock rock-rock) is particularly important because it determines the safety factor in large part. Moreover, it is commonly accepted that the roughness of the surfaces of rock discontinuities determines the mechanical behavior in shear. This study is divided into two parts: a study of taking samples from two dams of Hydro-Quebec and the conception of an artificial rock-concrete contact. Firstly, from shear tests realized under constant normal load, achieved on contacts from two dams, the principal component study of mechanical and roughness parameters was conducted to determine the parameters dominate (Z2, Z4, Extent). In addition, a field classification of discontinuities is proposed. The latter depends on various parameters such as the angularity of the surface, filling or oxidation of the surfaces of the discontinuity. Artificial rock-concrete contact has been studied in its entirety by various statistical and geostatistical methods in order to describe as precisely as possible its surface roughness. Once the last known, a map of coring with a 150 mm diameter core sampler has been decided. The collected areas are those with features of roughness, for example, a high angularity. Once the coring performed, samples were tested for shear resistance under a constant normal load. It follows a study of mechanical and roughness parameter and an underline of scale effect
Rey, Stéphanie. „Fractionnement du poly(oxyde d'éthylène) et du polystyrène avec le mélange supercritique universel CO2/éthanol : approche du comportement microscopique et thermodynamique de ces systèmes“. Phd thesis, Université Sciences et Technologies - Bordeaux I, 1999. http://tel.archives-ouvertes.fr/tel-00007636.
Der volle Inhalt der QuelleJbily, Dalia. „Prise en compte de l’usure dans la modélisation du comportement sous charge des engrenages roues et vis tangentes“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI037/document.
Der volle Inhalt der QuelleWorm gears are one of the technical devices for transmitting torque between spatial crossed axes. They provide a simple and cost effective solution in power transmission applications, where a high reduction ratio is required. Comparable conventional parallel axis gearing would normally require two or three stages to achieve the same reduction, with a consequent increase in complexity and number of parts. Surface wear is one of the failure modes observed in life worm gear sets which affects the contact patterns, the other transmission characteristics and the resultant noise. The first step of this work is the development of a numerical model to study provide the quasi-static behavior of worm gears with bronze wheel and steel worm. The model is based on solving of the equation of displacement compatibility and the influence coefficient method. The global effects of bending and local effects of contact are separated. The contact effects are obtained with the theory of Boussinesq. Bending effects are estimated by the combination of one standard FEM computation and interpolation functions. These methods allow, on the one hand, to take into account the environment of the gear (shaft shape, rim, web, bearing location ...) and on the other to reduce significantly the computation time. In a second step, a methodology is proposed for predicting the wear of the wheel tooth surface. In this process, a quasi-static contact model of the load distribution is combined with Archard's wear model. This model assumes that the wear depth is directly proportional to the contact pressure and sliding distance and inversely proportional to the hardness of the material. The wear law is modified to take into account the influence of the lubrication conditions using a local wear coefficient, depending on the lubricant film thickness, relative to the amplitude of surface roughness. Removal of material by wear on the wheel flank affects the pressure distribution, therefore the changes in teeth must be included in the prediction of wear. The calculation of contact pressures must also be updated to take into account the modification of the gear flank geometry. The last step concerns the validation of the numerical. Comparisons have been carried out between the model results and experimental ones issued from the bibliography
Bui, Hong Son. „Etude de l'influence physicochimique des environnements gazeux sur le comportement tribomécanique du bi-sulfure de molybdène MoS2“. Poitiers, 2012. http://www.theses.fr/2012POIT2331.
Der volle Inhalt der QuelleThe aim of this study is to characterize experimentally and theoretically the evolution of the friction coefficient of molybdenum disulfide MoS2 in various gases such as in the high vacuum at 10-5 Pa and in the various components gases of the ambient air. We present and discuss the experimental results of the contact XC48/ MoS2/XC48. Our tribological tests are performed on a pin on disk tribometer which located in an ultra high vacuum chamber and which is equipped with one system of gas introduction valves. To clarify the effect of each gas, tribological tests were carried out in the high vacuum (10-5 Pa), in the helium and in the argon at 105 Pa as inert gases, in the nitrogen and in the carbon dioxide at 105 Pa as the less reactive gases, in the oxygen at 105 Pa as the strong reactive gas, in the water vapour with a permanent dipole and in the air ambient with or without the presence of moisture. The tribological nature of molybdenum disulfide MoS2 obtained in high vacuum will be discussed. The influence of gases on the tribological behaviour of molybdenum disulfide will be also discussed and interpreted according to the dipolar character of these gases. A simple calculation of interaction forces MoS2-gas in terms of Van der Waals forces will be presented. Moreover, the influence of Van der Waals forces according to the nature of the gas around the tribocontact on the elastic tensor or on the stress of cleavage of the anisotropic lamellar layers of MoS2 will be discussed too
Giraldo, soto Catalina. „Optimisation des techniques de surveillance et développement de l'analyse de données pour la caractérisation in-situ du comportement énergétique réel de l'enveloppe du bâtiment“. Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0041.
Der volle Inhalt der QuelleThe general objective of this doctoral thesis project is to advance in the reliability and optimisation of Monitoring and Control Systems for HLC estimation and decoupling, in order to be able to define a minimum energy Monitoring Kit for residential or tertiary buildings in the future. These monitoring kits should be as unobtrusive as possible and should allow the minimum amount of data to be reliably monitored which, together with a correct analysis, should allow the real behaviour of the building envelope to be characterised.Thus after presenting the existing in-use HLC estimation and decoupling methods, the analysis of the State of the Art on monitoring and control systems for in-use building envelope energy characterisation is performed. Thanks to this review on monitoring and control systems analysis, it has been found that the overall uncertainty of indoor and outdoor temperature (when presented) is always considered to be the manufacturer’s accuracy in the existing literature. Using only the manufacturer accuracy as the overall uncertainty for these two important measurements required for the in-use HLC estimation, might lead to strongly underestimating their real uncertainty and this underestimation would be propagated to the estimated HLC values. To deeply analyse this topic, which could generate serious reliability issues for the estimated HLC values, a three dimensional monitoring system has been designed and deployed in an office building. To analyse the overall uncertainty of the indoor air temperature measurement, four thermal zones within the office building have been monitored with a three dimensional approach. To analyse the overall uncertainty of the outdoor air temperature measurement, a three dimensional monitoring approach has also been implemented around the building envelope.Furthermore, the results of this analysis have allowed the identification of the best location for the indoor and outdoor temperature sensors on the monitored building. Besides, the quantification of the discrepancies between the value of the sensor accuracy given by the manufacturer and the experimental value of the sensor accuracy plus the monitoring and control system has also been analysed. Here, the main contribution of this thesis can be found: the methodology developed to allow the quantification of the overall uncertainty of intensive variable measurements such as indoor air temperature and outdoor air temperature on in-use buildings. This methodology not only allows us to obtain the overall value of these measurements’ uncertainty containing all sources of uncertainty (called Measurement Uncertainty), but also allows us to decouple the Measurement Uncertainty into the uncertainty associated to the random and systematic errors. This decoupling separates the value of the variance associated with the overall uncertainty into the sum of two variances, one variance associated with the uncertainty related to the systematic errors (called in the study, Sensor Measurement Uncertainty) and another associated with the uncertainty related to the random errors (called in the study, Measurement’s Spatial Uncertainty).On the other hand, from the analysis of the Co-heating and Average method to estimate the HLC, an extremely detailed monitoring system has been designed and implemented in a residential building. The aim of this extremely detailed monitoring system is to be able to analyse what the minimum required set of sensors to estimate and decouple the in-use HLC values with a sufficient reliability. The selected sensors have the greatest possible accuracy that could be found for building sector applications. A detailed economic analysis is also included for this extremely detailed monitoring
Borsali, Redouane. „Etude theorique du comportement dynamique des melanges ternaires de polymere en solution : etude experimentale par spectroscopie rayleigh quasi-elastique“. Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13138.
Der volle Inhalt der QuelleSERRE, ISABELLE. „Comportement d'une serie d'esters de l'acide oleique sur cuticules vegetales et effets sur la penetration foliaire d'herbicides“. Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10244.
Der volle Inhalt der QuelleZarzour, Noura. „Modélisation, identification structurelle et estimation du facteur de comportement pour les bâtiments en maçonnerie géo-sourcée dans les zones sismiques“. Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5056.
Der volle Inhalt der QuelleThe use of new low-carbon construction materials in seismic areas requires the assessment of the structure ductility in order to properly design the building. The lack of accurate structural performance estimation limits the use of green construction materials.A reliable methodology is established for the seismic design of buildings constructed using geo-sourced materials. In particular, a pilot project of compressed earth block (CEB) masonry building in a medium-high seismic hazard zone in Southern France is developed. Starting from the experimental characterization of material mechanical parameters, the seismic design approach focuses on the modal characteristics of the structure, the expected building ductility, and seismic performance assessment in terms of both displacement and force.The equivalent frame model adopted for structural design of load-bearing masonry is validated for two case studies: a rubble stone masonry building and a CEB masonry building. The model validation process consists of the comparison of natural frequencies and mode shapes obtained by both numerical and operational modal analysis. In this context, a measurement campaign provides the structural response to ambient vibrations and then, the modal parameters and structural damping are obtained by structural identification tools. The modal analysis highlights the impact of timber slab stiffness on the dynamic response of masonry buildings. It is shown that a stiffer timber slab with a reinforced topping improves the structural behavior of the masonry structure under seismic loading, yielding to global mode shapes.The stability verification of the building structure at the near collapse limit state is performed in terms of target to capacity displacement ratio, but it is suggested to verify also in terms of force, since it can be more restrictive in some instances and less dependent on the convergence of numerical procedures.The behavior factor in seismic codes for building design is defined for typical construction materials based on damage observation and numerical models. A specific assessment is needed when new construction materials are adopted because building codes provide only boundary values. This thesis proposes a procedure for estimating the behavior factor that is applied to geo-sourced masonry buildings, but it could be adopted for any construction material. The methodology proposed to estimate the force reduction factor, and then the behavior factor, integrates both the seismic demand and building capacity. For this reason, this methodology can be considered as a capacity-demand-based approach. A nonlinear quasi-static analysis is coupled with dynamic analyses and the behavior factor is obtained on a statistical basis. The results are compared with the estimations obtained using demand-based, capacity-based and N2-based approaches. The impact of adopting a three-dimensional building model or an equivalent single-degree-of-freedom system with these methodologies is analyzed.The proposed capacity-demand-based-method provides, with a reduced computation time, a reliable estimation of the force reduction factor, close to the values obtained using the capacity-based-approach applied to a three-dimensional building model that is considered as a reference. Consequently, considering their reliability and efficiency, the proposed methodology for the behavior factor estimation is suitable for professional practice
Plée, Vincent. „Prédiction du comportement de phases et des enthalpies de mélange de gaz naturels atypiques contenant de l'argon, du monoxyde de carbone et de l'hélium“. Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0186/document.
Der volle Inhalt der QuelleThe development of the predictive E-PPR78 model, based on a contribution group method, has been undertaken since ten years to predict accurately the behaviour of multi-component systems. This model lies on the Peng-Robinson equation of state with classical Van der Waals mixing rules. It uses a unique binary interaction parameter, kij, which is temperature dependant. To enable the E-PPR78 model to predict the behavior of natural gases, three new groups are added: carbon monoxide, helium and argon. It was necessary to build an experimental database, as exhaustive as possible, containing phase equilibrium and enthalpies of mixing data for binary systems formed by these groups and those defined in previous studies and present in natural gases. After a description of the classification scheme of Van Konynenburg and Scott, the E-PPR78 model is described. The third part is about the addition of the three new groups to the model. It clearly appears that the E-PPR78 model is able to predict the fluid-phase behavior of natural gases over wide ranges of temperatures and pressures
Hannel, Sophie. „Sur l'importance de la transition de glissement en fretting pour la connectique“. Ecully, Ecole centrale de Lyon, 2000. http://www.theses.fr/2000ECDL0027.
Der volle Inhalt der QuelleOn all mobile electronic devices, vibrations lead to fretting stresses on electrical connectors contacts. Resulting contact damages hinder the current flow. The main result of this research is the correlation between the electrical behaviour and the fretting sliding condition : for oxygen sensitive materials such as bronze or tin, a partial slip condition guarantees a low and stable electrical resistance, whereas a gross slip condition leads to an irreversible increase and a strong instability of contact résistance. For oxygen insensitive materials such as gold or silver, the electrical behaviour is conditioned by substrate exposure which sooner or later occurs in gross slip. The technological interest lies in the demonstration of a threshold in relative displacement for a satisfactory electrical behaviour. In order to calculate this threshold and thus anticipate the contacts electrical behaviour, a mechanical analysis using 2D finite element modelling of the elastic plastic contact is applied to the experimental bronze/bronze contact. The experimental determination of a relevant friction coefficient, essential input parameter for the efficiency of the model, required an analysis the results of which might be extended to any contact situation involving intense adhesion and plastic deformation. The analysis consists in separating the friction coefficient from obstacle effects and plastic shearing of the interface. Thanks to this analysis, the calculated relative displacement at transition corresponds to that measured in experiments. This experimental validation of the model opens the way to a predictive analysis of the connectors electrical behaviour
Benhmida, Saïd. „Robustesse et comportement asymptotique d'un TRA-estimateur des coefficients d'un processus ARMA (p,q)“. Nancy 1, 1995. http://www.theses.fr/1995NAN10035.
Der volle Inhalt der QuelleCarjaval, Moncada Claudio Andrés. „Evaluation probabiliste de la sécurité structurale des barrages-poids“. Clermont-Ferrand 2, 2009. https://hal.archives-ouvertes.fr/tel-01298893.
Der volle Inhalt der QuelleAlboussière, Thierry. „Magnétohydrodynamique et ségrégation solutale en croissance Bridgman horizontale“. Grenoble INPG, 1994. http://www.theses.fr/1994INPG0153.
Der volle Inhalt der QuelleGuilhen, Pierre-Michel. „Prédiction du comportement dynamique des rotors dans le cas d’équations à coefficients periodiques : instabilité – réponse aux balourds“. Lyon, INSA, 1988. http://www.theses.fr/1988ISAL0026.
Der volle Inhalt der QuelleCharles, Sylvain. „Mise en place d’un dispositif expérimental de caractérisation du comportement des lames fluides, identification des coefficients dynamiques“. Poitiers, 2004. http://www.theses.fr/2004POIT2342.
Der volle Inhalt der QuelleIn many industrials applications, mechanisms such as turbines or pumps function under sever operating conditions: high speed of rotation, high pressures and high Reynolds number. The dynamic behavior of the shaft strongly depends on shaft surroundings elements like journal bearing or annular seals. Many studies use numerical simulations to recreate real operating conditions, but it is necessary to compare theses results with those coming from an experimental test facility. That is why the LMS and its industrial partnerrs (ALSTOM, EDF, CNES, SNECMA) decided ten years ago to design a specific test apparatus for studying annular seals. The functioning of the machine is completely described in this document. In parallel with the project, the behavior law of a thin-walled orifice is studied; the both numerical and numerical studies give the same result for the discharge coefficient. It does not, in this case, correspond to the value from literature. Finally, the last part of the research deals with the development of a specific method to identify the dynamic force coefficients characterizing the behavior of a seal. Many methods use Fourier transformations to work in frequency domain, whereas this methods stay in time domain. Numerical simulations were carried out, but even if the noise is high, results are good. The algorithm is robust, and the main parameters are identified
Guilhen, Pierre-Michel. „Prédiction du comportement dynamique de rotors dans le cas d'équations à coefficients périodiques instabilités, réponse au balourds /“. Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376141077.
Der volle Inhalt der QuelleHu, Dawei. „Contribution à l’étude du comportement mécanique et hydromécanique d’une roche endommagée“. Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10150/document.
Der volle Inhalt der QuelleThis thesis presents the laboratory and numerical investigations on anisotropic mechanical, poromechanical and fluid transport behavior of sandstone. After the X-ray and SEM tests, the samples were stressed under triaxial loading to study the initial and stress-induced mechanical behavior. The evolution of anisotropic Biot’s coefficients and axial permeability are also investigated and related to mechanical behavior. A plastic damage model is presented based on discrete approach. The proposed model is applied to simulate the mechanical behavior of dry sandstone under different loading conditions, the evolution and distribution of damage variable and plastic hardening variable are also discussed. Furthermore, the proposed model is applied to simulate the previous experimental results (including mechanical behavior, Biot's coefficients and permeability) of saturated sandstones. The comparisons between the numerical result and test data show a good performance of the present model. Finally, an anisotropic poroplastic damage model is developed to describe the poromechanical behavior of saturated sandstone. The comparisons between numerical simulation and experimental data is given for the triaxial compression tests under drained and undrained condition, the tests of strain response to pore pressure increment is also simulated, a good accordance is obtained
Diop, Awa. „Sur la discrétisation et le comportement à petit bruit d'EDS unidimensionnelles dont les coefficients sont à dérivées singulières“. Nice, 2003. http://www.theses.fr/2003NICE4069.
Der volle Inhalt der QuelleThe first part of this thesis is devoted to the approximation of one-dimensional stochastic differential equations (SDE) with non Lipschitz coefficients. More precisely, we consider two classes of equations which are often used in finance. We first consider a generalization of Cox-Ingersoll-Ross and Hull & White models ; the drift coefficient has bounded derivatives whereas the diffusion coefficient is of type σ (x) = xα, with ½ ≤ α < 1. We then consider a SDE solved by a Bessel process ; the drift coefficient is of type C on α, with C > 0 and thus presents a singularity at zero. Under our assumptions, one has existence and uniqueness of solution with almost surely strictly positive trajectories. For these two SDE’s we propose a discretization schemes which preserve the positivity of the approximated processes. On one hand we obtain the convergence rate in the weak sense when the test functions are smooth. On the other hand, we analyze the convergence rate in the strong sense in the case where the diffusion coefficient is of type σ (x) = xα. In the second part of this thesis, we consider the problem of the asymptotic behaviour of the solution of a parabolic partial differential equation (PDE) with discontinuous first order coefficient when the viscosity goes to zero. Under a monotonicity assumption on the first order coefficient, we show that the solution converges weakly towards the “measure solution” of the corresponding transport equation
Zhang, Yuanyuan. „Friction prediction for rough surfaces in an elastohydrodynamically lubricated contact“. Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI063.
Der volle Inhalt der QuelleThe friction of interfacial surfaces greatly influences the performance of mechanical elements. Friction has been investigated experimentally inmost studies. In this work, the friction is predicted by means of numerical simulation under an elastohydrodynamic lubrication (EHL) rough contact condition. The classical Multigrid technique performs well in limiting computing time and memory requirements. However, the coarse grid choice has an important influence on code robustness and code efficiency to solve the rough problem. In the first part of this work, a coarse grid construction method proposed by Alcouffe et al. is implemented in the current time-independent EHL Multi-Grid code. Then this modified solver is extended to transient cases to solve the rough contact problem. The friction curve is usually depicted as a function of “lambda ratio”, the ratio of oil film thickness to root-mean-square of the surface roughness. However this parameter is less suitable to plot friction variations under high pressure conditions (piezoviscous elastic regime). In the second part of this work, the friction coefficient is computed using themodified EHL code for many operating conditions as well as surface waviness parameters. Simulation results show that there is no single friction curve when the old parameter "lambda ratio" used. Based on the Amplitude Reduction Theory, a new scaling parameter depends on operating condition and waviness parameters is found, which can give a unified friction curve for high pressure situation. For more complex rough surfaces, a power spectral density (PSD) based method is proposed to predict friction variations in the third part of this work. The artificial surface roughness is employed to test the rapid prediction method firstly. Good agreement is found between the full numerical simulation and this rapid prediction. Then the rapid prediction method is applied to analyze the friction variation of measured surface roughness. Both the new scaling parameter and the friction increase predicted by the PSD method show good engineering accuracy for practical use
Targaoui, Mourad. „Étude du comportement hydrodynamique des joints à rainures hélicoïdales. Caractérisation du pouvoir d'étanchéité“. Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2289/document.
Der volle Inhalt der QuelleThe viscoseal is one of the contacts less sealing technical solutions used in machinery. This device is designed for very specific applications requiring durability and non-tolerance leakage past the limits that can satisfy joints contact. The viscoseal is characterized by the friction absence due to radial clearance well above the asperities amplitudes and the manufacturing defects. The sealing is obtained by the helical grooves formed in one of its internal surfaces. These grooves induce a hydrodynamic phenomenon that synthesizes same pumping rate of the same order as the leakage rate.In this work, a numerical model is proposed to calculate the seal in the viscoseal. Based on the thin film theory, the behavior of the latter is determined by the calculation of the pressure field and the filling that satisfy the Modified Reynolds Equation (MRE). The latter allows managing the borders of the film breaking and reformation. Resolution is made by the finite element method.The sealing power characterization in the viscoseal is made by the "sealing length" that specifies width of the fluid full area, in the axial direction, when the sealing is established. This domain extension is unknown, it iterates over the length of the seal until a zero axial flow over the edge. However, in the sealing depends on several geometrical and operating parameters. It is about the shape of the grooves, their angle orientation of and the journal speed.First, an optimal operating geometry was determined. Turbulent aspects of flow and thermal behavior, according to a global heat balance, are also studied. Finally, the introduction of eccentricity effects allowed approving dynamic phenomena in the viscoseal
Andrianatrehina, Soanarivo Rinah. „Comportement hydro-mécanique des sols fins compactés au voisinage de la saturation. : application aux remblais routiers“. Thesis, Le Havre, 2016. http://www.theses.fr/2016LEHA0030.
Der volle Inhalt der QuelleThe thesis presents an experimental study on very high plasticity soils compacted near of the standard Proctor optimum (SPO). It is performed as part of the ANR TerreDurable project which is devoted on the design of earthworks with fine soils. After the study of the effect of compaction on drying-wetting paths, induced cracking of drying is highlighted and analyzed. Furthermore, relationships between different mechanical parameters (modulus, IPI, compressive strength) and water (suction, permeability) according to the energy of compaction and method of preparation are shown. The mechanical behavior of soils compacted fine soils is studied on saturated and unsaturated, drained and undrained oedometer and triaxial. For the unsaturated undrained triaxial, the change in Skempton parameters pore pressure is analyzed on isotropic and deviatoric paths. This required the development of a triaxial cell equipped with psychrometers, tensiometer and strain gauges
Kachmar, Ayman. „Problèmes aux limites issus de la supraconductivité : estimations semi-classiques et comportement asymptotique des solutions“. Paris 11, 2007. http://www.theses.fr/2007PA112070.
Der volle Inhalt der QuelleThis thesis is devoted to the study of various models for the `proximity effect' in the frame work of the Ginzburg-Landau theory of superconductivity. These models arise in the situation when a superconductor is adjacent to a normal metal. In a first part of this thesis, we estimate in the semi-classical limit the ground state energy of a magnetic Schrôdinger operator associated to a Fourier (Robin) type boundary condition, called in this context the de Gennes boundary condition, and we study the localization of the ground states. We exhibit cases when the de Gennes boundary condition has strong effects on this localization. In another part, we formulate a spectral problem related to the onset of superconductivity for a generalized Ginzburg-Landau functional having discontinuous coefficients, where the order parameter and the magnetic potential are defined in the whole space In the regime when the Ginzburg-Landau parameter (of the superconducting material) is large, we estimate the critical applied magnetic field for which the normal state will lose its stability. In some asymptotic situations, we recover results related to the `standard' Ginzburg-Landau model. In the final part, we study again a generalized Ginzburg-Landau functional in the case without an applied magnetic field. We determine in this case the asymptotic behavior of the order parameter in the regime when the Ginzburg-Landau parameter is large. This shows in particular that the superconductivity persists in a thin boundary sheath of the normal material, near the boundary of the superconductor
Maythaveekulchai, Nopparat. „Etude des coefficients thermoréfractifs et photoréfractifs de matériaux diélectriques en couches minces, par l'analyse du comportement des lignes de mode obtenues avec le coupleur à prisme“. Aix-Marseille 3, 1991. http://www.theses.fr/1991AIX30077.
Der volle Inhalt der QuelleBoussier, Jean-Marie. „Modélisation de comportements dans les systèmes dynamiques : Application à l'organisation et à la régulation de stationnement et de déplacement dans les Systèmes de Trafic Urbain“. Phd thesis, Université de La Rochelle, 2007. http://tel.archives-ouvertes.fr/tel-00411272.
Der volle Inhalt der QuelleMokeddem, Abdelhammid. „Modélisation géomécanique et probabiliste des rideaux de palplanches : prise en compte de l’interaction sol-structure et de la variabilité spatiale du sol“. Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0057/document.
Der volle Inhalt der QuelleThe geomechanical behaviour of geotechnical structures such as sheet pile walls is subjected to epistemic uncertainties due to geomechanical models’ assumptions and also the aleatory uncertainties which could be related to the soil spatial variability. The main objective of this thesis is to gain more insight into the effect of these uncertainties on the sheet pile behaviour. To this end, this thesis focuses on four main issues: The first one is related on the one hand to the analysis of the used geomechanical hypotheses for modelling of retaining walls. On the other hand, to extend the one-dimensional subgrade reaction method which is based on a beam relying on elastoplastic supports to a two-dimensional system that call to an orthotropic plate relying on the same supports (MISS-CR-PLQ). The second issue concerns the soil spatial variability modelling. After a key comparison between two random field generation methods, we selected the Circulating Embedding method for its efficiency. Several parametric studies have been conducted to analyse the effects of different assumptions of random field generation. The third issue is related to the implementation of the proposed mechanical-reliability approach taking into account the soil spatial variability. The last issue is devoted to the application of the developed approach to a case study through probabilistic and reliability analyses. The influence of statistical parameters (e.g. correlation lengths, cross-correlation,...), mechanical and geometrical has been examined
Du, Dianchun. „Design of tunnels using the hyperstatic reaction method“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI063/document.
Der volle Inhalt der QuelleThis research work aims to present the design of tunnel by means of the Hyperstatic Reaction Method (HRM). The models developed by the HRM method are firstly proposed for investigating the behaviour of U-shaped tunnels under different conditions, considering two load cases, two different geometries of U-shaped tunnel lining, two different cases of springs, change of the spring stiffness, multi-layered soil conditions, surcharge loading, and saturated soil masses. The presented models permit to obtain good predictions with a high computational efficiency in comparison to finite difference numerical modelling. Then a parametric analysis has permitted to estimate the U-shaped tunnel lining behaviour in a large number of cases which cover the conditions that are generally encountered in practice. Thereafter, taking a twin-lane metro tunnel as an example, a series of mathematical functions used in the optimization progress of sub-rectangular tunnel shape is deduced, which gives to tunnel designers a theoretical support to choose the optimal sub-rectangular tunnel shape. The effect of different parameters, like the lateral earth pressure factor, soil Young’s modulus, tunnel depth, surface loads, on the internal forces and shape of sub-rectangular tunnel is then given. In the last part of the manuscript, the influence of a temperature change on the lining forces of circular tunnel by means of the HRM method is investigated, considering different factors, such as the tunnel lining thickness, lining elastic modulus and ground coefficient of thermal expansion
Zokimila, Pierre. „Modélisation numérique du comportement thermomécanique de réseaux de galeries souterraines pour le stockage des déchets radioactifs : Approche par homogénéisation“. Phd thesis, 2005. http://tel.archives-ouvertes.fr/tel-00010925.
Der volle Inhalt der QuelleLa formation géologique hôte sera soumise à des chargements mécanique et thermique dus respectivement au creusement des ouvrages de stockage et au dégagement de chaleur des colis de déchets stockés. Ces chargements thermomécaniques vont engendrer une modification de la distribution des contraintes dans la couche hôte et les déformations des ouvrages ainsi que l'extension des zones endommagées (EDZ) pourraient provoquer des instabilités locales et globales.
Les objectifs de ce travail consistent en l'élaboration de techniques de calculs pour optimiser la modélisation numérique du comportement thermoélastique des ouvrages à grande échelle et en l'évaluation de la perturbation thermomécanique induite par le stockage sur la formation géologique hôte. Dans cette optique, après une présentation de l'état des connaissances sur les aspects thermomécaniques des roches liés au stockage souterrain, des modélisations numériques 2D et 3D du comportement thermoélastique d'ouvrage individuel et d'un réseau de galeries ont été réalisées par une approche discrète. Toutefois, cette approche classique est pénalisante pour l'étude du comportement global d'installations de stockage. Pour pallier à cela, une approche de modélisation numérique, basée sur la technique d'homogénéisation des milieux périodiques, a été proposée. Des formulations ainsi que des procédures numériques ont été élaborées pour déterminer le comportement thermoélastique effectif d'une structure hétérogène équivalente. Le modèle, obtenu par cette méthode, a été validé avec des méthodes d'homogénéisation existantes telles que le modèle auto-cohérent, ainsi que les bornes de Hashin-Shtrikman. La comparaison du comportement thermoélastique effectif avec le comportement thermoélastique réel de référence a montré une bonne cohérence des résultats. Pour une application au stockage profond, les coefficients thermoélastiques effectifs d'un réseau de galeries circulaires ont pu être déterminés en 2D pour différentes dimensions de l'entraxe des galeries.