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Academic literature on the topic 'Μicro-tomographie aux rayons X'
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Journal articles on the topic "Μicro-tomographie aux rayons X"
MAIRE, Eric, Pierre LHUISSIER, and Luc SALVO. "Tomographie aux rayons X synchrotron appliquée à la science des matériaux." Étude et propriétés des métaux, February 2016. http://dx.doi.org/10.51257/a-v1-m4398.
Full textDissertations / Theses on the topic "Μicro-tomographie aux rayons X"
Zhang, Tao. "Imagerie multi-résolution par tomographie aux rayons X : application à la tomographie locale en science des matériaux." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00876871.
Full textSaur, Hugo. "Étude des microstructures par tomographie à rayons X : application aux roches clastiques à grain fin." Electronic Thesis or Diss., Pau, 2022. http://www.theses.fr/2022PAUU3005.
Full textThe study of the microstructure of rocks is essential for our contemporary and future challenges in energy, engineering and construction. Furthermore, this study allows us to characterize the geological deformation processes that led to the current state of geological formations. Fine-grained clastic rocks, commonly called "shales", represent about two-thirds of all sedimentary rocks. 3D data concerning silt-sized grains or clasts embedded in the porous clay-rich matrix of this type of rock are relatively scarce despite the fact that these data are crucial to understand the anisotropic properties of these rocks at the macroscale but also to evaluate the deformation state of the rock matrix. A better understanding of the microstructure of these rocks would allow us to predict their mechanical or physical properties, which are essential for applications in the energy sector, among others. X-ray computed tomography (XCT) is a non-destructive technique providing a 3D image of the microstructure of any object. A direct geometric characterization of the constituents of fine-grained clastic rocks is possible with this technique. Based on XCT images, this thesis aims first to develop methodological aspects to study the 3D shape fabric of silt particles and their spatial distribution. The moments of inertia of segmented grains from 3D digital images are used for this development. We then present applications on fine-grained rocks with a sedimentary fabric and on deformed fine-grained rocks with a tectonic fabric. The first application part of the thesis focuses on the same lithologic unit having experienced different amounts of deformation. Samples from the South Pyrenean Basin and samples from a historical outcrop in the Central Appalachians were collected. We provide new data on the evolution of the 3D shape of grains and pores at the micrometer scale and their arrangement in the rock matrix with respect to the deformation intensity. The obtained data allow discussing the deformation mechanisms at the grain scale of the different mineralogical phases. However, the limited size of the imaged samples by means of XCT (≤ 2 mm diameter) raises the question of the representativeness of these analyses. On the South Pyrenean site, some samples are studied in more detail to evaluate the homogeneity of the results. We show that the XCT data complement the indirect petrophysical measurements by providing access to localized sub-fabrics that are integrated in a bulk measurement of the rock fabric. The limits are reached when the characteristic length of the deformation structures are on the order of the sample size imaged by XCT. In the second application part, samples from turbiditic systems of the South Pyrenean basin are analyzed. These systems, when deformed in compressive tectonic settings, record the same amount of shortening differently expressed in the various siliciclastic matrices. The results obtained from the shape data of the clasts are compared to our bulk magnetic fabric measurements and show a good consistency. The methodology presented in this work can be extended to other types of porous and granular media for a better understanding of the influence of fabric anisotropy on their macroscopic properties and mechanical behavior
Lenoir, Nicolas. "Comportement mécanique et rupture dans les roches argileuses étudiés par micro tomographie à rayons X." Université Joseph Fourier (Grenoble), 2006. http://www.theses.fr/2006GRE10025.
Full textWITHIN THE FRAMEWORK OF FEASABILITY STUDIES OF UNDERGROUND REPOSITORIES FOR RADIOACTIVE WASTE, THE STUDY OF PERMEABILITY EVOLUTION WITH DAMAGE OF THE HOST LAYER IS CRUCIAL. THE GOALS OF THIS WORK WERE : (i) TO CHARACTERIZE EXPERIMENTALLY THE DAMAGE OF TWO CLAYEY ROCKS (BEAUCAIRE MARL AND EAST SHALE) WITH X-RAY MICRO TOMOGRAPHY, (ii) TO DEVELOPP A HIGH PRESSURE TRIAXIAL SET-UP ADAPTED TO PERMEABILITY MEASUREMENT ON VERY LOW PERMEABILITY ROCKS. A NUMBER OF ORIGINAL TRIAXIAL DEVICES HAVE BEEN REALISED TO CHARACTERIZE DAMAGE OF CLAYEY ROCKS, UNDER DEVIATORIC LOADING, WITH X-RAY MICRO TOMOGRAPHY ON A SYNCHROTRON BEAMLINE AT THE ESRF (GRENOBLE). LOCALIZED DAMAGE AND ITS EVOLUTION HAVE BEEN CHARACTERIZED AT A FINE SCALE (OF ORDER OF TEN MICRONS). DIGITAL IMAGE CORRELATION TECHNIQUES, EXTENDED TO 3D IMAGES, HAVE BEEN USED TO MEASURE INCREMENTAL STRAIN FIELDS FROM TOMOGRAPHIC IMAGES. WE DEMONSTRATED THAT THESE TECHNIQUES ARE VERY USEFUL IN THE STUDY OF THE LOCALIZED DAMAGE OF GEOMATERIALS AND ESPECIALLY FOR THE INITIATION. A HIGH PRESSURE TRIAXIAL DEVICE HAS BEEN REALISED TO MEASURE PERMEABILITY EVOLUTION OF THE EAST SHALE AS A FUNCTION OF APLLIED STRESS (ISOTROPIC AND DEVIATORIC). THE PARTICULARITY OF THIS SET-UP IS THE SMALL SIZE OF THE TEST SPECIMEN (CYLINDER OF 10MM IN DIAMETER AND 20MM IN HEIGHT) WHICH ALLOWS SIGNIFICANT REDUCTION OF TEST DURATION
Badel, Pierre. "Analyse mésoscopique du comportement mécanique des renforts tissés de composites utilisant la tomographie aux rayons X." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0085/these.pdf.
Full textThe preforming stage of the RTM composite manufacturing process leads to fibrous reinforcement deformations which may be very large especially for double curvature shapes. The knowledge of the mechanical behavior of the reinforcements and their mesoscopic deformed geometry is necessary for various applications. A simulation method for woven composite fabric deformation at mesoscopic scale is presented. A specific continuum hypo-elastic constitutive model is proposed for the yarn behavior. The associated objective derivative is based on the fiber rotation. Spherical and deviatoric parts of the transverse behavior are uncoupled. X-ray tomography is used to obtain experimental undeformed and deformed 3D geometries of the textile reinforcements. The simulations performed on representative elementary volume are validated based on mechanical experimental tests and tomography images for the geometry
Petit, Clémence. "Etude des propriétés mécaniques de matériaux cellulaires par la tomographie aux rayons X et par modélisation par éléments finis." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0130/document.
Full textCellular materials are highly porous systems for which two scales are mainly important: the mesostructure and the microstructure. The mesostructure corresponds to the architecture of the materials: distribution of solid phase “walls” and macroporosity and can be characterized by X-ray tomographic low resolution images. The link between the architecture of the materials and the mechanical properties has been frequently studied. The microstructure refers to the characteristics of the solid phase. Its microstructural features (presence of a secondary phase or of defects due to the sintering) can have a strong influence on the macroscopic properties. The aim of this work is to link the morphological and microstructural features of metallic and ceramic based cellular materials and their mechanical properties thanks to X-ray tomography and finite element modelling. A new method combining X-ray tomography at different resolutions, image processing and creation of finite element modelling enabled to take into account some microstuctural features of the cellular samples. Four different cellular materials were studied as model materials: aluminium foam fabricated by a liquid state process, cobalt periodic structures made by additive manufacturing, β-TCP porous samples fabricated by conventional sacrificial template processing route and hydroxyapatite/β-TCP composites made by additive manufacturing (robocasting). The metal based materials were provided by colleagues while the ceramic based porous materials were fabricated in the frame of the current study. For each type (metals or ceramics), a stochastic and a regular structure have been compared. For implementing the multiscale method developed in this work, the samples were firstly scanned in a so called “local” tomography mode, in which the specimen is placed close to the X-ray source. This allowed to reconstruct only the small irradiated part of the sample and to obtain a magnified image of a subregion. These images enable to observe some details which are not visible in lower resolution. Different image processing steps were performed to generate low resolution images including microstructural features imaged at high resolution. This was done by a series of thresholding and scaling of the high resolution images. The result of these processing steps was an image of the initial sample. Then, in situ mechanical tests were performed in the tomograph to follow the deformation of the sample at low resolution. The above mentioned initial images were used to produce finite element meshes. Special Java programs were adapted to create finite element input files from initial images and meshes. The initial images containing information about the solid phase, the images from the mechanical tests and the finite element models were combined to explain the mechanical behaviour of the sample by linking the experimental damage locations in the sample and the simulated stress concentration sites
Li, Jia. "Simulation par éléments finis de la propagation de fissures de fatigue dans les matériaux polycristallins imagés par tomographie aux rayons X." Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0079/document.
Full textThe short fatigue crack propagation in polycrystal materials depends strongly on microstructure. Although numerous studies of characterisation and of simulation, the prediction of the short fatigue crack propagation remains a challenge.In order to understand the mechanisms of short fatigue crack propagation, an in-situ characterisation by X-ray tomography was carried out at ESRF, using two techniques of tomography. Diffraction Contrast Tomography (DCT) that is a non-destructive method can be used to obtain 3D morphology and grain orientations in an undeformed state of polycrystal materials. Couple with Phase Contrast Tomography (PCT), it allows to characterise the short fatigue crack propagation at different loading stages. Access to this information, it is possible to simulate the short fatigue crack propagation using a 3D reel microstructural mesh reconstructed from the tomographic images.In this work, the elastic anisotropic behaviour in a 3D microstructural mesh is performed. The elastic strain tensors averaged in grains are also compared to the experimental measurements. Then, a new numerical approach is proposed to simulate crack propagation. From a crystal plasticity FE simulation, the crack growth direction is determined by a post processing. Next, the crack is propagated through remeshing. This approach is firstly applied to the single crystals, then to the polycrystal mesh reconstructed from the tomographic images. The grain boundary effects and the crack growth rate are also analysed. By comparing between simulation and experimental crack, the damage indicator is discussed at the end
Amani, Yasin. "Modélisation basée sur données de tomographie aux rayons X de l'endommagement et de la conductivité thermique dans les matériaux cellulaires métalliques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI036/document.
Full textThe properties of cellular materials depend on their architecture and casting defects. The architecture refers to shape and distribution of the solid phase. Defects correspond to the presence and distribution of cavities or intermetallic particles in the solid phase due to the fabrication procedure. Two types of materials produced by different fabricating routes are studied in this manuscript. On the one hand, two ERG foams with different cell sizes were chosen to study the effect of the presence of intermetallic particles on the plasticity and damage. Micro-tensile tests and nanoindentation experiment were also performed on the struts extracted from the foam to determine their micro elastoplastic behaviour. On the other hand, two structures with the same shape and repetitive pattern but different struts and nodes thicknesses were produced by selective laser melting manufacturing route to study the effect of porosity on plasticity and damage. This PhD-work aimed at developing a generic image-based finite element procedure to take into account the effect of the local porosity and the presence of intermetallic particles into the finite element simulations of the cellular materials. The initial state of the samples was pictured by performing high resolution "local" tomography and "stitching" methods. The 3D geometries were meshed and the local porosity and elastic-plastic properties of each element were directly informed according to high-resolution 3D images. The deformation and fracture procedures of the samples were pictured by performing in-situ/ex-situ experiments coupled with low-resolution tomography scanning. 3D image-based finite element models were developed for the simulation of the tension/compression tests. The microstructurally informed FE models better capture the mechanical behaviour of the cellular structures, especially for the prediction of the fracture. The study also aimed at determining the thermal conductivity of a highly porous ERG foam using image-based finite element calculations. The results were verified by comparing with the measured thermal conductivity from guarded hot plates experiments
Pinson, Sébastien. "Matériaux architecturés pour refroidissement par transpiration : application aux chambres de combustion." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI089/document.
Full textIn order to cool aero-engine combustion chambers as efficiently as possible, there is today a special interest given to transpiration cooling technology. The cooling air flows through a porous liner in which a large amount of heat can be exchanged by convection. The air injection could then take benefit of the pore distribution to form a more homogeneous protective boundary layer.Partially sintered metallic materials are potential candidates to form these porous liners. The present work focuses on internal heat transfers. It aims to develop a methodology capable of highlighting the most adapted partially sintered architectures to this kind of application.During transpiration cooling, flows and heat transfers are governed by some effective material properties which depends on the porous architecture: the effective solid phase thermal conductivity, the volumetric heat transfer coefficient and the permeability properties. Thanks to experimental works and numerical studies on samples digitized by X-ray tomography, simple relationships are first developed between the effective material properties of partially sintered materials and their architectural parameters. The porosity, the specific surface area and the powder type are selected to predict the effective properties.These relationships are finally integrated into a heat transfer model predicting the thermal performance of a design at working engine conditions. A multi-objective optimization and an analysis of the optimal designs highlight some architectures as being potentially interesting for transpiration cooling. Materials with a low porosity and made of large irregular powders seem to ensure the best trade-off among the different criteria taken into consideration
Bouterf, Amine. "Comportement mécanique de la plaque de plâtre étudié par tomographie et essais mécaniques in-situ." Thesis, Cachan, Ecole normale supérieure, 2014. http://www.theses.fr/2014DENS0010/document.
Full textLightweight plasterboard is a product composed of a "plaster foam" core whose porosity can reach 75% lined with two sheets of paper. To optimize the compromise between thermal resistance and mechanical strength, it is important to understand and characterize the mechanical behavior of the plasterboard. In the present work, specific methodologies for digital image correlation and identification of the mechanical behavior in highly nonlinear regimes (damage, collapse of porosity, macroscopic cracking ...) have been developed and implemented. A first set of mechanical properties, crucial for handling and placarding, concerns the bending strength. Three and four points bending tests were performed until failure. Digital image correlation was used to follow the kinematic of the test. The behavior of the plasterboard has been identified through a homogenized continuum description based on plate kinematic where the progressive degradation of bending stiffness is described through a damage law. A specific procedure for identification is presented where experimental imperfections and symmetry breakdown are tolerated and accounted for. The analysis shows that the mechanical behavior of the plasterbaord in bending test is controlled primarily by the mechanical properties of the paper lining and the quality of gypsum / paper interface. The failure mechanism in bending test was also identified through in-situ tests performed inside the tomograph. A second category of mechanical properties relates to a normative test “Nail pull test”. Through tests conducted inside the tomograph and the analysis of the kinematics by digital volume correlation, the different key stages of the failure mechanism have been identified. The compaction of the core by the collapse of porosity in compression has been recognized as the limiting factor. In order to better understand the compaction mechanism in-situ spherical indentation tests were performed on foamed samples prepared from the board core. The results from the in-situ experiment show that a compacted zone develops under the indenter, displaying a very sharp boundary with the undamaged material that behaves elastically. To meet the need for estimating accurately the state of multiaxial strain that characterizes this transition, a new methodology is presented. It is an integrated digital volume correlation based on a library of fields adapted to the spherical indentation test and computed from commercial finite element software. Coupling in-situ mechanical tests, digital volume correlation and numerical simulations on the one hand, and integration a priori known information in the identification process on the other hand allowed us to identify a local failure criterion. The behavior of porous plaster was also characterized via homogeneous triaxial tests, by following different loading paths. The triaxial behavior of foamed plaster has been identified. The results are in agreement with those obtained via the identification procedure conducted on the spherical indentation tests
Lesseur, Julien. "Imagerie 3D des matériaux et modélisations numériques : application aux multi-matériaux ferroélectriques." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0178/document.
Full textThis thesis is focused on the conception of new tunable ferroelectric/dielectric compositematerials. Dielectric granules (MgO, TiO2) obtained by spray-drying are dispersed in a ferroelectricmatrix (Ba1-xSrxTiO3). Mixing powder is then densified by Spark Plasma Sintering (SPS). An originalapproach is developed in order to determine parameters linking the microstructure to the physicalproperties for each step of the elaboration - characterization - modelling optimization procedure.The adopted strategy is based on i) specific SPS properties which provide an accurate control of theinterfaces between each components; ii) potentialities offered by X-ray microtomography to describethe internal 3D microstructure of the composite materials during the key steps of their elaboration.Associated with powerful image processing tools, it allows to obtain relevant elements guiding theoptimization and understanding of the final properties; iii) the development of a 3D numerical modelof tunability applied directly to the real geometry which has been extracted from 3Dmicrotomography images. This step is essential to understand the origin of the redistribution of theelectric field between the different phases. Numerical results are directly compared to experimentalmeasurements