Дисертації з теми "Matériaux composites Al"
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Mahmoud, Bassam. "Modélisation d'impacts sur des stratifiés composites unidirectionnels et hybrides." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30212.
Повний текст джерелаToday, composite materials are largely used in the manufacturing of aeronautical structures, in order to lighten their weight. Impact on composite structures is one of the most detrimental loading. The present study aims to develop a predictive modelling of impacts on thin unidirectional laminates in order to, firstly, better understand the damage mechanisms involved, and, secondly, be able to provide guidance for a strength improvement of these structures. First, an explicit finite element modelling of unidirectional laminates is developed based on the work of F Pascal dealing with impact modeling on helicopter blades. Thus, a new element that can represent the impact response of unidirectional plies is formulated. The behavior of the bundle of fibers is modeled with rod elements stabilized with specific 2D elements. The degradation is managed using damage based on experimental observations. The parameters of the proposed modelling strategy are identified on the basis of experimental tests carried out on T700/M21 and HTA7/913 composites. The results provided by the modeling are then validated by a comparison with experimental low velocity impact results. Finally, in order to improve the laminate strength, low velocity and medium velocity impacts on hybrid unidirectional/woven composite laminates are studied experimentally and with the developed modelling strategy
Leloup, Jean-Michel. "Matériaux composites conducteurs protoniques." Montpellier 2, 1993. http://www.theses.fr/1993MON20219.
Повний текст джерелаKchit, Nadir. "Piézorésistivité des matériaux composites magnétorhéologiques." Nice, 2008. http://www.theses.fr/2008NICE4075.
Повний текст джерелаWe have studied the conductivity of the composite material made of micron-sized nickel particles embedded in a silicone elastomer matrix in response to the applied pressure, temperature and magnetic field. The composite was cured at 80°C or at the ambient temperature and in the presence of an external magnetic field, in such a way that the magnetic particles formed structures aligned with the field. The samples cured at room temperature appeared to be non-conductive at zero pressure but very sensitive to the applied pressure. The resistance of these samples can vary from a few G at zero pressure to a few for a pressure ranging between 20 and 200 kPa, depending on the nature of conductive particles. For the same type of the composite, we have also obtained a very strong magnetoresistance - more than four orders of magnitude variation in resistance for a field ranging between 0 and 200 kA/m. However, the samples structured at 80°C show a low initial resistance at the end of cooling, and are much less sensitive to the applied pressure. We used these samples to study the thermoresistance: while heating, the resistance increases from a few to a few G We have developed a model to predict the behavior of these piezoresistive materials, which takes into account the surface roughness and the thickness of the oxide layer. Using this model, we characterized the residual thickness of the polymer layer between particles as well as the behaviour of such surface layer in the presence of a mechanical stress
Lesseur, Julien. "Imagerie 3D des matériaux et modélisations numériques : application aux multi-matériaux ferroélectriques." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0178/document.
Повний текст джерелаThis 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
Grange, François. "Matériaux composites pour antenne miniature intégrée." Phd thesis, Université Rennes 1, 2010. http://tel.archives-ouvertes.fr/tel-00601825.
Повний текст джерелаLei, Yannick Ruani. "Matériaux composites électroactifs à porosité contrôlée." Montpellier 2, 2009. http://www.theses.fr/2009MON20074.
Повний текст джерелаAmong all systems for electrical storage, electrochemical devices are interesting because they turn chemical energy into electrical energy. Supercapacitor and Li-ion battery have high power density and good energy density, respectively. The topic of the present work is the preparation of composite electrode material MnO2/C for supercapacitor, SnO2/C for Li-ion battery and synthesis of porous SiC. This could be achieved starting by the synthesis of mesoporous carbon (900m2/g) following a hard template method. At first, the evaluation of electrochemical performances of composite electrode material for supercapacitor shows two different behaviours versus the ratio of MnO2. We could observe an optimal ratio for which capacitance was maximal (900F/g). Secondly, the volumic variations occurring while charge/discharge of SnO2/C electrode materials are contained by the carbon matrix. In spite of limited electrochemical performances for pure SnO2 electrode material, the cyclability of SnO2/C electrode materials is enhanced. At last, the synthesis of porous SiC can be achieved by the thermal reduction of SiO2/C composite using Mg as reducing agent. The as-prepared material is a replica of silica template
Duong, Ngoc Tan. "Cartographie et caractérisation acoustiques des matériaux composites : application à l’évaluation du taux volumique de porosité dans un matériau composite RTM." Thesis, Le Havre, 2015. http://www.theses.fr/2015LEHA0023/document.
Повний текст джерелаThe porosity of a composite plate in carbon / epoxy of type RTM is known by used of tomography X. A method of determination of this porosity by measure of the mitigation of the longitudinal waves through the thickness of this kind of plate is proposed. These measures are made on surfaces of different sizes (from some cm2 to some mm2) and allow the obtaining of cartographies. A correspondence porosity (tomo X) - Mitigation (US wave) is deducted and analyzed according to the structure of the composite material. In every case, we estimate the quality of the obtained relations and we deduct the limits of validity of the correspondence between porosity and mitigation. First results of acoustic tomography are obtained
Ratiarisoa, Lisa Barbara. "Etude de matériaux naturels 2D : Potentialités d'utilisation comme renfort de matériaux composites." Thesis, Antilles, 2019. http://www.theses.fr/2019ANTI0393.
Повний текст джерелаFacing the worldwide environmental, social and economic crisis awareness, the possibility ofreinforcing composites by a lignocellulosic textile reinforcement, the coconut leaf sheaths fromCocos nucifera L. was assessed in this work. The exploratory phase of sheaths characterizationhas shown that this resource forms a two-way textile made up of cellulose mostly. In contrast toclassic vegetable reinforcements, it is less hygroscopic, lighter with best tensile mechanicalproperties in preferential fibers directions. About the experimental campaign on the treatmentseffect, xylanase and laccase treated sheaths show a slight surface chemical change. Pyrolysedfibers are more hydrophobic but less resistant translating a damaging of them. Lime treatedsheaths show a higher thermal stability. Thus, raw sheaths were retained to reinforceparticleboards, the temperature of panels manufacture being lower than the start degradationtemperature of the raw sheaths. The two-faces panel covered with raw sheaths top part forms themost promising candidate to develop thermal eco-insulator. Some of its mechanical and physicalproperties fulfill american and european standards. Its thermal properties are similar to the onesnoticed in the bibliography for low density lignocellulosic particleboards
Senghor, Fiacre Djonkone. "Identification des propriétés anisotropes des matériaux complexes : application aux matériaux composites stratifiés." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4002/document.
Повний текст джерелаThe works presented in this thesis focuses on the identification of anisotropic electrical properties of complex composite materials. They aim to contribute to a better control of the impact of manufacturing process parameters, different architectures, formulations and fibres filling rate, etc., on the electrical behaviour of these composite materials. They inscribe themselves in the frame of the FUI ACCEA research project funded in part by the region Pays de la Loire. This project aims to produce a multi-functional composite material of a new type of thermoplastic matrix loaded with carbon graphite which would see its electrical and thermal properties improved without degrading the mechanical properties. From then one of the main difficulties of the designer is to find innovative implementation tools, to improve the thermal and electrical properties of these composites non-intrusive and non-destructive to their mechanical properties with less cost. It is in this logic that this PhD work is interested in modelling and experimental measurement of the electrical conductivity tensor of this composites to provide an help to the decision on the choice of matrix, of the weave, the implemented method, etc. The comparison between the simulation and experimental results gives a good concordance
Leroux, Julien. "Modélisation numérique du contact pour matériaux composites." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00961209.
Повний текст джерелаTalbot, Philippe. "Introduction à l'étude des matériaux magnétiques composites." Brest, 1993. http://www.theses.fr/1993BRES2010.
Повний текст джерелаFADEL, LARBI. "Etude par frottement interne des matériaux composites." Poitiers, 1993. http://www.theses.fr/1993POIT2268.
Повний текст джерелаFonblanc, Gilles. "Mousses syndactiques : matériaux composites pour grandes profondeurs." Bordeaux 1, 1986. http://www.theses.fr/1986BOR10517.
Повний текст джерелаHassler, Ulf. "Tomographie X bi-énergie de matériaux composites." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0049.
Повний текст джерелаReig, Patrice. "Les phyllosiloxydes : de nouveaux matériaux d'interphase lamellaires tout-oxyde pour matériaux composites." Bordeaux 1, 1995. http://www.theses.fr/1995BOR10521.
Повний текст джерелаAzran, Aymeric. "Intégration de fonctions sur matériaux composites innovants pour l'aéronautique." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22625.
Повний текст джерелаAeronautical industry is made of compromises between the performances and the costs. The main goal is to reduce the mass in order to increase either the flight range or the useful mass. This document presents the innovative way to design composite materials based on a new textile technology and as a consequence a new way of design strategy. I’ll focus on two industrial applications which consist in adding new features to composite materials in order to reduce the number of parts and so on the global mass. The first application is the conception of a thermally conductive composite material which could allow a new way to design on flight computers andelectronic devices. The second application is focused on the non developable shape parts. In this application, I’ll show how we have added mechanical properties to new textile architectures in order to obtain a better mass/performance factor
Chafi, Haysam. "Optimisation des efforts dans un ancrage courbe collé acier/composites." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1221/document.
Повний текст джерелаComposite materials are gaining increasing interest in most of the industry sectors due to their low self-weight and their interesting physico-chemical properties. However, the use of these materials called for parallel reflections on their assembly with other materials which gave rise to the development of the structural bonding technology. This technique which allows to assemble materials of different natures by limiting, for example, the increase in the self-weight of the structure, is not fully mastered yet. For this purpose, further development on the qualification of the adhesion forces or on the understanding of durability are still necessary. This thesis addresses the problem of the optimization of adhesive bonded joints and aims in particular to study, more precisely, the use of the curvature in order to optimize the transfer of forces within the bonded joint. Two types of adhesive, one exhibiting a fragile elastic behavior and the other an elastoplastic behavior, have been studied in this work on the various analytical, numerical, and experimental aspects. We presumed that the plasticity of the adhesive appears to improve the strength of the bonded joints and; hence, shall be considered as an essential parameter in their optimization. A study of the curved geometry of the steel / composite bonded joints was then carried out, where it emerged that this geometry was effective in increasing the strength of the bonded joint and its ultimate capacity. Moreover, in order to extend the knowledge on the mechanical behavior of the curved bonded joints, and in the absence of sufficient bibliographical references on this type of bonding, we then resorted to the modeling by using the cohesive zone method to also validate the advantage of the curved geometry with respect to the plane geometry. This work finally focuses on the mechanical durability of this solution by addressing the fatigue thematic; even if additional investigations are needed, we have already found that the optimization of the joint by the use of an elastoplastic adhesive, and a curved geometry can improve the fatigue behavior of the adhesive bonded joints
Chabert, Erwan. "Matériaux composites à matrices vitrimère et polymère supramoléculaire." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066285/document.
Повний текст джерелаWe describe the use of two polymer matrixes with unusual properties for long glass fibres reinforced composite materials and fully organic composites. Vitrimers, recently discovered in the Soft Matter and Chemistry laboratory constitute a new class of polymers as they can exhibit high mechanical strength and are insoluble even at high temperatures like thermosets and yet, like thermoplastics, they are heat processable, recyclable and weldable. The question arises whether this welding property is maintained in composite materials made of more than 50vol% of reinforcing fibres. We quantitatively and statistically analyze the bond strength of lapshear vitrimer composite joints autogenously welded by heat and compare the results to comparable joints of standard thermoset epoxy. It is demonstrated that only vitrimer samples show substantial bond strength and the ability to be repeatedly welded thanks to the exchange reactions that promote both bonding between the adherands and the decrease of surface roughness at the joint interface. This opens the way towards joining composite parts without adhesives or mechanical fasteners. We also explore a composite system made of woven glass fibres and of a matrix base on supramolecular semi-crystalline polyamides that have been developed in the SMC laboratory. Their very low melt viscosity is an asset to envision improved manufacturing and recycling methods. As a proof of concept, composite material pieces have been subjected to a high temperature water treatment. We show the complete recovery of both the neat woven glass fibers plies and the matrix. Finally, we show that actuators can be made from bilaminar vitrimers
Lachi, Mohammed. "Détermination des diffusivités thermiques des matériaux composites par méthode flash bidirectionnelle." Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL006N.
Повний текст джерелаThomas, Benjamin. "Matériaux composites Argent/Carbone à propriétés thermiques adaptatives." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0140.
Повний текст джерелаDue to their high thermal conductivity, metal matrix composite materials reinforced with carbon allotropes exhibit a high potential application for thermal management in electronics. This work deals with the elaboration of new synthesis process to produce Ag/rGO (silver/reduced Graphene Oxide) and Ag/GF (silver/Graphite Flakes) composite materials. This process, based on “molecular level mixing” methods, makes it possible to obtain Ag/rGO composite powders with individualized nano-reinforcements up to a concentration of 1 % in volume. Applied to the synthesis of Ag/GF composite materials, it allows to synthesize dense composite materials with a graphite concentration up to 70 % in volume and with a thermal conductivity up to 675 Wm-1.K-1 (426 Wm-1.K-1 for pure silver). Moreover, it has been shown that Ag/GF powders elaboration process has a strong influence on the structural anisotropy of bulk materials as well as on the extrinsic thermal boundary resistance Ag-graphite. The process developed in this work allows Ag/GF composite materials to reach thermal conductivity up to 19 % higher than the same materials synthesized by conventional mixing powder process. However, like most metal/GF composite materials (with Cu, Al, Mg and Fe matrix), thermal expansion of Ag/GF composite materials shows “anomalies”. Indeed, the anisotropy of their coefficient of thermal expansion (CTE) is opposed to their structural anisotropy, their CTE has an abnormally high dependence on temperature and these materials exhibit dimensional instability during thermal cycling. While it is commonly admit in literature that these “anomalies” are the consequence of internal stresses generated during materials densification (because of CTE mismatch between matrix and reinforcement), this phenomenon remains poorly understood and difficult to control. A significant part of this work is devoted to the study of these anomalies and especially to the study of the influence of matrix mechanical properties on composite materials thermal expansion. Thanks to EBSD, XRD, instrumented microhardness and microscopy analysis, key phenomena responsible of thermomechanical behavior of Ag/GF composite materials have been identified. Especially, it has been shown that a large part of the internal stresses is relaxed by plastic deformation of silver matrix and pseudo-plastic deformation of graphite during the post-densification cooling step of the materials. Thus, the control of mechanical properties of metallic matrix (especially of its elastic limit) makes it possible to attenuate the anomalies in CTE and confers a better dimensional stability to Ag / GF composite materials during thermal cycling. Finally, the addition of rGO in silver matrix of Ag/GF composites materials has also reduced material dimensional instability by up to 50 % thanks to the damping properties of rGO
Junker, Nicolas. "Conception et dimensionnement de pièces de robinetterie en matériaux composites." Paris, ENMP, 2001. http://www.theses.fr/2001ENMP1053.
Повний текст джерелаHaddad, Mohamed. "Développement d'un procédé d'enroulement filamentaire adapté aux matériaux composites sandwich et caractérisation mécanique des matériaux." Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0031.
Повний текст джерелаComposite materials, and especially sandwich structures, have been studied for decades. Indeed, the association between lightness and resistance of these structures leads to the development of their use. Their manufacturing method and their characterization remain as essential points in most studies. This work is part of the FUI SOLLICITERN project, which aims to design a composite water treatment tank for vehicles intended for this purpose. As a first step, and based on the classical filament winding principal, we aim to search designs that are best adapted to the fabrication of a curved sandwich material on a cylindrical mandrel, while respecting the process parameters of and their influence on structural properties. Since an optimal solution was validated, the constituent materials were studied by measuring mechanical properties. The objective is to help our industrial partner to validate a manufacturing solution and verify that such properties are the expected ones. For that, several static and dynamic characterizations were carried out on curved samples manufactured by the optimized process designed for our application. This part includes various experimental tests in order to validate the structure behavior with the most appropriate dimensions and material combinations, taking into account the manufacturing process. At the end, the best structural configuration is retained for the first tank prototype fabrication
Giordano, Fabrice. "Sur des nanocomposites à base de matériaux naturels." CDhambéry, 2006. http://www.theses.fr/2006CHAMS010.
Повний текст джерелаLn this study, we synthesize a DGEBA- TETA epoxy system incorporating three different kinds of natural resources in order to improve some properties of pristine polymer. It has been found that introducing epoxidized soybean oil (ESO), toughens epoxy resin against shock due to its role as a diluant and plasticiser. Homogeneous distribution of elastomer nodule sizes through the phase separation effect leads to an increase in resistance to deformation and crack initiation in the epoxy resin. The lack of residual miscibility between DGEBA and ESO at the phase separation point is an interesting phenomenon, since it makes ESO an attractive product in polymer blends. The second part of this work deals with the modification of two montmorillonite smectite clays, a commercial one called N757, and another one extracted from quarries in the Vietnamese province of Lâm Dông, in order to make them exploitable for nanocomposite applications. The Montmorillonite surface modification technique used is a novel treatment by intercalation of the curing agent TETA which is based on the electrostatic interaction between the original exchangeable montmorillonite cations and TETA. The efficiency of surface modification with TETA is confirmed by the formation of an intermediate exfoliated state in the final nanocomposite. The third part of the thesis focuses on bacterial cellulose, a natural material made of a nanometric fibrillar network. To reduce the hydrophilic nature of cellulose surfaces, a novel chemical grafting process, described as a "chromatogenic chemistry" method, is carried out to provide stronger interfacial adhesion with the polymer. The Essential Work of Fracture (EWF) method has been used to show the efficiency of this method in the case of aged samples
Coquelle, Eric. "Propriétés élastiques et viscoélastiques de matériaux composites adaptatifs." Phd thesis, Université de Nice Sophia-Antipolis, 2004. http://tel.archives-ouvertes.fr/tel-00009415.
Повний текст джерелаmécaniques contrôlées par un champ magnétique. Ils sont composés de particules magnétiques,
structurées en chaînes unidirectionnelles au sein d'une matrice élastomère silicone. Les essais sous
champ ont révélé un fort accroissement des propriétés mécaniques : jusqu'à 35kPa pour un module de
62kPa en traction statique, et en dynamique un gain sur E' de 600kPa à ε=1%, qui atteint même
21MPa à ε=10-5 ! Dans ce dernier cas, la structuration en chaînes va de pair avec une nette
augmentation de l'effet Payne et de la dissipation d'énergie, encore accentuée en présence d'un
champ, même modeste (15kA/m). L'hypothèse avancée est un décollement progressif de l'élastomère
des charges sous l'effet des fortes contraintes locales, entre deux particules (en quasi-contact). Pour
faciliter l'étude, un traitement de surface à base de molécules couplantes, fonctionnelles, a été mis au
point. La modélisation a d'abord été effectuée sur un système macroscopique (où tous les paramètres
sont contrôlés), et validée par des simulations par éléments finis (FEM). Une méthode de milieu
effectif prédit le comportement du composites aux charges greffées (avant décollement), tandis qu'une
approche semi-analytique, utilisant un critère de décollement de Griffith, calcule le comportement
viscoélastique du composite MR. La complexité de la microstructure et son évolution ont été évaluées,
sous champ, par des cycles quasi-statiques (aboutissant à des σ de -40kPa à ε=0) et des mesures de
magnétostriction. D'autres propriétés originales peuvent être obtenues : piézorésistivité, bandes
périodiques (guides magnétiques).
Wassereau, Thibault. "Caractérisation de matériaux composites par problème inverse vibratoire." Thesis, Le Mans, 2016. http://www.theses.fr/2016LEMA1041/document.
Повний текст джерелаThe increasing use of composite materials in the industry leadsto new challenges in various areas, including non-destructiveevaluation. Common methods such as modal analysis or finiteelements are rarely appropriated to represent the complexvibratory dynamic of composite structures or quantify theirviscoelastic properties, new approaches are then needed.This thesis deals with the development and application of a localinverse vibratory method, called the Force Analysis Technique(FAT), in order to the study multilayer composites. The latterare considered to be homogeneous using the Timoshenko beamtheory, which takes shear effects into account, usually significantfor such structures. A frequency and/or spatial characterizationof the equivalent elastic parameters (Young’s modulus E, shearmodulus G and their associated loss factors) isthen possible to accurately interpret the dynamical behaviourof composite materials and also simplify their implementationin finite element software.A second approach using a corrected finite difference scheme(CFAT method) allows a similar analysis using a coarse mesh,reducing the durations of measurement and post-processing.Finally, a perspective of detection and identification of defects isconsidered. By mean of cartographies of the elastic parameters,it seems possible to infer a signature related to a kind of flaw. Adiscontinuity of the shear modulus would attest the presence ofdelamination while a reduced Young’s modulus could indicate afibre breakage, etc
Lin, Yueguo. "Comportement thermoélectrique de matériaux composites pour applications aéronautiques." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2013. http://www.theses.fr/2013ESMA0012/document.
Повний текст джерелаComposite materials – since their high specific properties – are used recently to reduce the weight of aircraftstructures and to improve the performance engine in order to reducing the emissions of CO2. Composites of Carbon FibberReinforced Polymer matrix (CFRPs) are increasingly used in civil aviation industry for the production of structural parts:fuselage panels.Integrating CFRPs in the aeronautical structures has also some difficulties: the fuselage – generally subject to pressure of airflux – would be subjected also to shocks/impacts, particularly will be damaging for exposed to the aggressive environment(temperature, humidity, liquid cooling, ...).The fuselage is the principal structure to support the charge of electric current, such as those related to the electric current returnto ground or lightning : although the secondary networks of electrical cables and wires fences are provided to support thesecharges, the action of leakage currents, probably passer through bolted and riveted joints and because of the high differences ofelectrical potential between the surface of panels thickness, can activate the thermoelectric coupling and lead to localizedheating of these structures. Phenomena related to this type of coupling may be particularly remarkable in CFRPs – since thepolymer matrices is electrically and thermally quasi-insulates, for composite the thermoelectric behaviour is highly anisotropic– and need further research and investigation. The integration of micro and nano fillers – especially carbon nanotubes (CNTs) –in the polymer resin or in interface of fibber/matrix can improve the overall behaviour, but it is a technological solution that stillrequires be explored in detail.The aim of this work is to characterize the anisotropic properties of thermoelectric behaviour of materials CFRPs – charged oruncharged in CNTs. This characterization includes:· measurement of electrical resistivity/conductivity and their evolution with temperature,· characterization of the temperature fields induced by the passage of electric current,· identification of parameters for modeling the behavior of these thermoelectric materials and interpretation oftests,· characterization of the effect of moisture aging on the values of resistivity/conductivity of the composite
Ringuette, Benoît. "Matériaux composites à base de fibres de chanvre." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28057/28057.pdf.
Повний текст джерелаEl, Mouden Mustapha. "Une nouvelle méthode d'homogénéisation des matériaux composites élastiques." Metz, 1995. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1995/El_Mouden.Mustapha.SMZ9545.pdf.
Повний текст джерелаWe propose to modelize the mechanical behavior of heterogeneous media. It is in that context we have developed a three variants of a new analytical approximate method called cluster, for predicting the effective moduli of heterogeneous media, to account for the interaction between the heterogeneiti at finite concentration. The spatial distribution of the heterogeneiti is accounted for in our scheme. In this cluster scheme we consider each grain is embbeded in a spherical cluster constitued by several layers of neighbouring grains. The cluster is itself suspended in the homogeneous reference medium. When the radius of the cluster is increased, the resultats of the cluster scheme were shown to converge. The variants of this method are denominated respectively cluster (by taking the homogeneous matrix as a reference medium and a auxiliary strain applied at infinite), cluster-Mori-Tanaka (by taking the homogeneous matrix as a reference medium and the average strain of the matrix applied at infinitie, this method is a generalization of the Mori-Tanaka modele) and cluster-selfconsistent (with the homogeneous equivalent medium as reference medium and the overalll strain applied at infinite, this is an extension of the classical self consistent scheme). The two first variants was applied to a composite medium consisting of ellipsoidal elastic inclusions embedded into anather elastic medium (matrix), even though the last method was applied to certain composites with log fibers. Compared with experimental data, analytical solutions and finite elements calculations, the present approach provides reasonably accurate predictions for effective moduli of composites materials with periodic microstructures
Morvan, Jean-Marie. "Comportement anélastique des matériaux composites à matrice céramique." Bordeaux 1, 1997. http://www.theses.fr/1997BOR10668.
Повний текст джерелаKharrat, Souhaib. "Comportement en fatigue thermique des matériaux composites réfractaires." Bordeaux 1, 1995. http://www.theses.fr/1995BOR10525.
Повний текст джерелаIsner-Brom, Pascale. "Nouveaux matériaux composites polymères piézoélectriques pour transducteurs électroacoustiques." Lyon, INSA, 1996. http://www.theses.fr/1996ISAL0023.
Повний текст джерелаThe first part of this study deals with realization, polarization and characterization of vinylidene fluoride and trifluoroethylene based ferroelectric copolymer elements with thirty percent trifluoroethylene. We also studied the moulding process, the temperature stabilization of these thick materials. In a second part, we present three further methods for characterizing these materials. The first one, “PWP”, or propagation wave pulse, the second method is based on the impedance and phase measure, and the third method consists in measuring the propagation velocity in various directions from different copolymer samples to obtain the intrinsic piezoelectric coefficients in the three directions. This last method is very important to modelize the “clamping effect” described in the last part of our work. The last part of the book describes the copolymer clamping effect with thick electrods. This configuration allows higher sensibility. Experimental data and calculations, with two different models, on this particular configuration are compared. In both cases, experimental results are in good agreement with calculations
Vives, Serge. "Synthèse et caractérisations de matériaux composites zircone/tungstène." Montpellier 2, 1994. http://www.theses.fr/1994MON20012.
Повний текст джерелаPeyroux, Robert. "Caractéristiques thermoélastiques de matériaux composites à fibres courtes." Montpellier 2, 1990. http://www.theses.fr/1990MON20090.
Повний текст джерелаCouturier, Laurent. "Comportement mécanique de matériaux composites à matrice aluminium." Compiègne, 1998. http://www.theses.fr/1998COMP1103.
Повний текст джерелаAngoulvant, François. "Caractérisation dynamique des matériaux composites : étude de l'amortissement." Le Mans, 1998. http://www.theses.fr/1998LEMA1011.
Повний текст джерелаPideri, Catherine. "Matériaux composites élastiques : comparaison de quelques méthodes d'homogénéisation." Paris 6, 1987. http://www.theses.fr/1987PA066579.
Повний текст джерелаPoussines, Laurence. "Développement de nouveaux matériaux pour l'infusion de composites." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0132/document.
Повний текст джерелаThe work presented in this thesis was done to adapt a polymer to selected elaboration process by infusion of a composite material structure for an aircraft fuselage. The polymer system must meet certain requirements such as viscosity, infusion temperature, storage but also the price. Our methodology is to understand the process putting into practice in order to validate the resins choice, to characterize the initial state and the study their sustainability towards a hydrothermal ageing. Properties characterization showed different behaviours in initial state, in terms of glass transition, resilience and viscosity. The study of hydrothermal ageing reveals a drop properties closely related to the chemical evolution of polymer networks which has for major origin multiple links hydrolysis. At least an adherence test is carried out to assess the interface fiber/resin. This test was used to estimate the different surface treatments on the fiber
Smaili, Arezki. "Développement de matériaux composites pour la réfrigération magnétique." Thèse, Université du Québec à Trois-Rivières, 1998. http://depot-e.uqtr.ca/6846/1/000642386.pdf.
Повний текст джерелаGauthier, Edouard. "Comportement mécano-fiabiliste de structures composites – approche matériaux." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0031/document.
Повний текст джерелаThe use of composite materials increases in the world of industry, particularly in sectors such as aeronautics, transport or energy production and this development leads to a strong production of composite structures, including large dimensions. The design of these composite structures requires a thorough knowledge of the mechanical behavior of the composite to ensure the integrity of the structure. However, the mechanical behavior of composite materials is heterogeneous in nature with a certain variability on the different mechanical parameters. This variability is caused by two main sources: the intrinsic variability of the material due to physical variations within the composite, and the variability due to defects in implementation. The thesis, which is presented, focuses on this second source of variability, namely the presence of implementation defects and its influence on the mechanical behavior of the composite. Two defects of implementation are studied in this thesis, porosity and wrinkle, following a probabilistic analysis. The first part of the study brings together all the state of the art on porosity and wrinkle defects, as well as on probabilistic analyzes in the field of composites. A second part of the study is devoted to the probabilistic characterization of porosity and wrinkle defects by analyzing the variability of each characteristic parameter of the defect and modeling it using a distribution law that are implemented in a calculation code to numerically model the experimentally observed porosity. A third part of the study focuses on the influence of porosity and wrinkle defects on quasi-static and fatigue mechanical behavior. This mechanical study compares the results of experimental tests on a healthy material, two materials with two different porosity states and two materials with a wrinkle of different dimensions, in order to be able to quantify the influence of the defect and to determine a model of degradation of mechanical properties according to the defect. The quasi-static mechanical study is supplemented by an analysis of the variance in order to separate the variability of the mechanical properties due to the defect and that due directly to the test itself. All the results of this study thus make it possible to identify the two types of defects with a set of characteristic parameters, as well as their influence on the mechanical behavior, while taking into account the variability observed on the defects and their mechanical influence, and to model numerically all these observations
Agopian, Jean-Charles. "Développement, caractérisation et optimisation de matériaux composites hybrides." Electronic Thesis or Diss., Université Clermont Auvergne (2021-...), 2022. http://www.theses.fr/2022UCFAC107.
Повний текст джерелаClimate change will require a more sober industry, in which “green” materials may play a key role. This also applies to composite materials, and every possibility to reduce their carbon footprint might be considered, while maintaining acceptable performance and durability levels.Partial replacement of carbon fibres by flax fibres is for instance a way to reduce the environmental impact of these composite materials. Surface energies of the fibres being quite different, the properties of the composite materials resulting of such a hybridisation might not be optimised. Moreover, flax fibres are hydrophilic, which rises two problems: they are poorly compatible with hydrophobic polymers, and can lead to a decrease of the durability of the composite, more susceptible to absorb water.In this study, a treatment by direct fluorination by molecular fluorine F2 has been implemented, aiming at level the surface energies of the fibres and increase their affinity with the matrix polymer. This work is mainly dedicated to the fluorination of carbon fibres, while another simultaneous doctoral project focused on flax fibre fluorination.First, a state of the art on the fluorination of carbon fibres has been realised, and published as a literature review, where the versatility of the carbon-fluorine bond and the experimental conditions leading influencing it were carefully described.It has then been shown by a wide variety of physicochemical analyses that room-temperature fluorination of carbon fibres was a way to fluorinate their sizing, and thus to tailor their surface energy. The same treatment was carried on a wide temperature scale, successively highlighting a sizing fluorination and hyperfluorination, and then a fluorination of the carbon fibre, leading to a huge increase of its hydrophobicity, and a decrease of its polar component.These fluorinated carbon and flax fibres were then integrated in an epoxy matrix by infusion process, with several stacking sequences. Mechanical tests do not show an improvement of the fibre-matrix compatibility thanks to fluorination, which might be explained by the high-quality interface allowed by sizing for the non-fluorinated fibres. Wet ageing tests are however promising, as composites made with fluorinated fibres absorb less water than composites made with non-fluorinated fibres
Baumberger, Stéphanie. "Obtention et caractérisation de matériaux composites amidon-lignines." Paris, Institut national d'agronomie de Paris Grignon, 1999. http://www.theses.fr/1999INAP0009.
Повний текст джерелаBarret-Vivin, Virgile. "Revêtements hybrides pour la protection de matériaux composites." Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066756.
Повний текст джерелаThe main purpose of this thesis was to provide an alternative to replace a fluorinated polymer film used in the aerospace industry (commercialized by Dupont de Nemours): the Tedlar®. To that end, several inorganic network based films have been studied. They have been synthesized by sol-gel chemistry. We furthermore investigated the behavior of a silica based matrix containing a perfluorinated organosilane. By adding in the mixture some nano and micro-particles, the spray-obtained films exhibit exceptional dewetting properties. In addition to their super hydrophobic behavior, those films are also lipophobic. To achieve all the specifications this project needs, a second matrix, involving an interpenetrated organic / inorganic framework, has been studied. These new films, which are UV-light initiated, showed very good properties: we characterized the mechanical ones by nano-indentation while the swelling of these coatings and their barrier properties have been examined by ellipsometry. The inorganic densification has been monitored by solid state 29Si NMR MAS and the organic polymerization by FTIR, 1H and 19F liquid RMN and 13C solid NMR. The creation of an hybrid network with fluorine at the surface and in the width of the films has permit to obtain coatings with all the requirements of our specification need
Chabert, Erwan. "Matériaux composites à matrices vitrimère et polymère supramoléculaire." Electronic Thesis or Diss., Paris 6, 2015. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2015PA066285.pdf.
Повний текст джерелаWe describe the use of two polymer matrixes with unusual properties for long glass fibres reinforced composite materials and fully organic composites. Vitrimers, recently discovered in the Soft Matter and Chemistry laboratory constitute a new class of polymers as they can exhibit high mechanical strength and are insoluble even at high temperatures like thermosets and yet, like thermoplastics, they are heat processable, recyclable and weldable. The question arises whether this welding property is maintained in composite materials made of more than 50vol% of reinforcing fibres. We quantitatively and statistically analyze the bond strength of lapshear vitrimer composite joints autogenously welded by heat and compare the results to comparable joints of standard thermoset epoxy. It is demonstrated that only vitrimer samples show substantial bond strength and the ability to be repeatedly welded thanks to the exchange reactions that promote both bonding between the adherands and the decrease of surface roughness at the joint interface. This opens the way towards joining composite parts without adhesives or mechanical fasteners. We also explore a composite system made of woven glass fibres and of a matrix base on supramolecular semi-crystalline polyamides that have been developed in the SMC laboratory. Their very low melt viscosity is an asset to envision improved manufacturing and recycling methods. As a proof of concept, composite material pieces have been subjected to a high temperature water treatment. We show the complete recovery of both the neat woven glass fibers plies and the matrix. Finally, we show that actuators can be made from bilaminar vitrimers
Aubert, Alex. "Synthèse, caractérisation et modélisation de matériaux multiferroiques (magnétoélectriques) composites massifs." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLN036/document.
Повний текст джерелаThe direct magnetoelectric effect is defined by the modification of the electric polarization induced by a magnetic field. Although this effect exists intrinsically in some materials, here we study the extrinsic effect, where the magnetoelectric effect results from an intermediate coupling between two distinct phases. In this case, the most common idea is to mechanically couple (by gluing) a piezoelectric material to a magnetostrictive material. Thus, by applying a magnetic field, the magnetostrictive material is deformed and transmits a stress to the piezoelectric material which makes its polarization change.In this thesis, we are interested in two types of laminar magnetoelectric composites: those using soft magnetostrictive ferrites (nickel ferrite) and those using semi-hard ferrites (cobalt ferrite). For each composites, we want to optimize the magnetoelectric effect by highlighting the parameters that mainly influence this coupling. As a result, we deal with different aspects such as the influence of the demagnetizing effect in multilayers, the volume fraction in the composites, the secondary phases, the dynamic magnetostriction, the uniaxial magnetic anisotropy, and finally the frequency and the amplitude of the magnetic exciting field on the magnetoelectric effect. Thanks to the understanding of the physical phenomena involved and the optimization of the resulting magnetoelectric coupling, we have been able to develop a current sensor with characteristics comparable to currently marketed current sensors that use other technologies (Hall effect, current transformer)
Koutsawa-Tchalla, Adjovi Abueno Kanika C.-M. "Contribution à la modélisation multi-échelle des matériaux composites." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0119.
Повний текст джерелаWe propose in this thesis several approaches for improving the multiscale modeling and simulation of composites’ behavior. Accurate and reliable modeling of the mechanical response of composite materials remains a major challenge. The objective of this work is to develop simplified methodologies based on existing homogenization techniques (numerical and analytical) for efficient prediction of nonlinear behavior of these materials. First choice has been focused on the Mean-field homogenization methods to study the elasto-plastic behavior and ductile damage phenomena in composites. Although restrictive, these techniques remain the best in terms of computational cost and efficiency. Two methods were investigated for this purpose: the Incremental Scheme Micromechanics (IMS) in One-site modeling and the Mori-Tanaka model in multi-site modeling (MTMS). In the framework of elastoplasticity, we have shown and validated by finite element method that the IMS homogenization results are more accurate, when dealing with high volume fraction composites, than the Mori-Tanaka model, frequently used in the literature. Furthermore, we have extended the Mori-Tanaka's model (MT) generally formulated in One-site to the multi-site formulation for the study of elasto-plastic behavior of composites with ordered microstructure. This approach shows that the multi-site formulation produces consistent results with respect to finite element and experimental solutions. In the continuation of our research, the Lemaître-Chaboche ductile damage model has been included to the study of elasto-plastic behavior in composite through the IMS homogenization. This latest investigation demonstrates the capability of the IMS model to capture damage effects in the material. However, the issue on the loss of ellipticity was not addressed. Finally we develop a numerical homogenization tool based on computational homogenization. This novel numerical tool works with 2D and 3D structure and is fully integrated in the conventional finite element code ABAQUS through its subroutine UMAT. The (FE2) method offers the advantage of being extremely accurate and allows the handling of more complex physics and geometrical nonlinearities. Linear and non-linear cases were studied. In addition, its combination with ABAQUS allows the use of major resources provided by this software (a panel of toolbox for various mechanical, thermomechanical and electrical analysis) for the study of multi-physics problems. This work was validated in the linear case on a two-scale analysis in bending and compared to the multi-scale method ANM (Nezamabadi et al. (2009)). Extensive work will be needed later with applications on non-linear problems to highlight the value of the developed tool
Berrehili, Yahya. "Etude du comportement effectif des matériaux composites à constituants décollés." Paris 13, 1997. http://www.theses.fr/1997PA132006.
Повний текст джерелаChabot, Armelle. "Analyse des efforts à l'interface entre les couches des matériaux composites à l'aide de modèles multi particulaires de matériaux multicouches (M4)." Marne-la-vallée, ENPC, 1997. http://www.theses.fr/1997ENPC9710.
Повний текст джерелаThe aim of the thesis is to design a tool for engineers simple to use which is able to analyze 3D stresses responsible for edge delamination or transverse crackings in multilayed materials. In the first part of the dissertation, we built Multiparticle Models (M4) from 3D approximate stresses written as Legendre's z polynomials layerwise. Polynomial coefficients are (x, y) fields which are connected to generalized stresses. We use Hellinger-Reissner's formulation to deduce displacements and associate generalized strains. Writing the formulation stationary, we give equilibrium equations, boundary conditions and constitutive laws. According to the different approximate stress fields, we have 7n, 5n, 3n and (2n+1) (n: layer number) plane equilibrium equations. In the second part of the thesis, we test four models concerning the problem of the boundary traction conditions on any angles laminates and (0°, 90°)s laminate with circular opening. We write analytically the systems of equations which condense on y second order of differential system of equations and whose resolution is performed by MATHEMATICA. On (0°, 90°)s laminate without hole, we show that miss stresses energy of reduced models do not disappear but is transferred on these still remaining stresses. On the simplest Multiparticle Model M4_(2n+1)M case, to ensure a global equilibrium of laminate, we propose a concept, which can be applied generally, of Dirac lineic stress whose intensity is connected with the maximum of edge shear stress. We think that it can be used as the essential information in order to define a criterion of delamination
Menessier, Erik. "Matériaux composites à matrice vitreuse ou vitrocéramique base silice." Bordeaux 1, 1988. http://www.theses.fr/1988BOR10710.
Повний текст джерелаMenessier, Erik. "Matériaux composites à matrice vitreuse ou vitrocéramique base silice." Bordeaux 1, 1988. http://www.theses.fr/1988BOR10638.
Повний текст джерелаCano, Miguel. "Contribution à l'étude du comportement mécanique d'un ruban de préimprégné dans le procédé de placement de fibres : analyse expérimentale et modélisation." Thesis, Clermont-Ferrand 2, 2010. http://www.theses.fr/2010CLF22093.
Повний текст джерелаThe evolution of composite materials in aerospace has been spectacular over the last thirty years. The main advantage provided by composites is weight gain compared to other materials. However, new aluminum lithium alloys may slow this trend because of their specific properties and exceptional manufacturing costs lower than those of composites. Much parts of the structure of the A380 are made from the latest generation of composite materials with organic matrix. The Airbus A380 is the first plane of the manufacturer composed by a center wing box made by composite reinforced with carbon fibers and organic matrix. And like the devices that preceded it, the center wing box, rudder, horizontal stabilizer and the elevators were designed with composites reinforced with carbon fibers and organic matrix. But the main challenge with the new aircraft is the size of parts ; the size of the horizontal stabilizer of the A380 for example, is similar to the wing of the A310. Hence the need to develop the intensive use of automatic prepreg lay up technology. The use of semi-finished prepregs for the manufacture of parts allows standardizing production. Indeed, these products exhibit with the desired rate of reinforcement on the final parts, all the delicate operations of pumping excess resin during the implementation of parts, as the case in the RTM process (Resin Transfer Molding) are eliminated. The quality of parts produced using automatic lay up depends on many factors including the accuracy of trajectory lay up, the control of rheology of the resin contained in the prepreg and behavior at the interface of the material and tooling. The rheology of the resin is changing considerably with environmental conditions (temperature, humidity) and processing conditions (speed of removal, compaction strength). It determines in part and in combination with the tackiness of the prepreg, the instabilities of the material particularly along curved trajectories. In curvilinear lay up, the rotation of the tow placement head imposes to this portion of slit tape, a curvature generating a circular bending phenomenon.The outer portion of the tape is then stretched while the inside is compressed. When the radius of curvature of the tow placement head is low, the result is a phenomenon of local buckling of the slit tape. The corresponding layer waviness (See figure 1) is visible after the passage of the roller so instantly or delayed, depending on the conditions of lay up (speed lay up,compaction strength, temperature, humidity) and the tackiness of the material. Thus, the formation of the layer waviness is a local phenomenon that appears in the material between the tow placement head and tools. It is this area of the material defined by the form of plate, and the extent of which depends on the compaction strength and flexibility of the roller which will be the model proposed in this communication. It is supposed that this plate is based on elastic foundation in order to reflect the tack of the material. The formation mechanism of ply waviness is very few studied and remains unclear since these defects appear at different steps in the manufacturing process. Some studies recommend, without justification, to not exceed some radius of curvature to avoid buckling [1]. Interactions between tooling and material in relation with lay up conditions were studied [2]. In this paper we study the mechanical behavior of a slit tape taking into account the rheology of the material so that his tack in order to better understand the conditions of appearance of layer waviness during circular trajectories. At first, we will present some results from the identification of physico-chemical and mechanical properties of prepreg carbon / epoxy and then we will explain the evolutions observed. A second part, complements the first,will be dedicated to the development of a model of mechanical behavior of a plate based onelastic foundation, representing the slit tape which is subjected to a rotation imposed. The mechanical model of the slit tape will be based on the theory of plate under the hypotheses of Kirchhoff-Love and Von-Karman. Determining the critical buckling load is carried by the Ritz method. The simulation results using different boundary conditions will be analyzed and compared to real cases