Dissertationen zum Thema „Matériaux composites fonctionnels“
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Allais, Manon. „Matériaux fonctionnels à base de polyphénols“. Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE021/document.
Der volle Inhalt der QuellePolyphenols are essential metabolites in vegetal kingdom. They have interesting properties both for healthcare and physical-chemistry : they are antioxidant, antimicrobial or anticarcinogenic and they are amphiphilic, hydrogen-bond acceptors and donors and they can chelate with metallic cations. This thesis aims to use a polyphenol : tannic acid (TA) to design functionnal materials. To begin, for a dental pulp engineerig purpose, TA was used to structure electrospun fibers of poly-lactic acid by using the technics of co-electrospinning-electrospraying. Then, for the first time, it was possible to electrospin fibres from a solution of pure TA. To consider applications, it was possible to cross-link these fibres. This result paves the way for a green synthesis of electrospun membranes. To finish, multilayer enzymatic films were made with TA and alkaline phosphatase or lysozyme. Films have both enzymatic properties and electro-activity due to TA
Azria, David. „Matériaux fonctionnels par assemblage de microsphères composites de chitosane/collagène pour l’ingénierie tissulaire“. Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEP043.
Der volle Inhalt der QuelleInjury of the peripheral nerve leads to local degeneration at the damaged site. If the injury results in a large nerve gap, spontaneous regeneration does not lead to functional recovery of the nerve. Among the several therapeutic strategies available, autograft is currently the most efficient technique but is associated with morbidity at the donor site. In the tissue engineering approach that we have investigated, nerve guides are typically elaborated with biocompatible materials to orient nerve outgrowth and regeneration. In this context, we have evaluated materials assembled with functionalized microspheres to form a gradient of neurotrophic factors with the aim of guiding nerve regeneration in the lumen of tubular conduits. We have studied the elaboration of chitosan and collagen microspheres from an emulsion generated in a controlled manner using a microfluidic technology. The solidification of the emulsion droplets was then achieved by the diffusion of ammonia vapors. The microspheres functionalization has been investigated and characterized using model fluorescent molecules, namely FITC (Fluorescein Isothiocyanate) and a protein (BSA, Bovine Serum Albumin) labeled with FITC. These functionalized microspheres were then assembled in the form of membranes with typical dimensions in the centimeter range, and exhibiting a functionalization gradient. Finally, preliminary experiments have demonstrated the possibility of animal implantation by rolling and suturing the membranes to a sectioned sciatic nerve. This work has allowed us to establish the proof of concept of this approach to elaborate functional nerve conduits and will need to be followed by complete study of functional nerve regeneration
Daoud, Hajer. „Contribution à l'étude du comportement mécanique et vibratoire des composites biosourcés incorporant des matériaux fonctionnels“. Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1017/document.
Der volle Inhalt der QuelleThis thesis focuses on the study of the mechanical and vibration behaviour of a flax fibre reinforced composites with and without an interleaved natural viscoelastic layer. The composite materials have been characterized experimentally using different mechanical and vibrational tests. First, both types of composites were studied using uni-axial tensile and three-points bending tests. Acoustic emission (AE) has been often used for the identification and characterization of micro failure mechanisms in composites. The results showed that these composites have very high specific characteristics. It can be used for applications currently using composites reinforced with synthetic fibres such glass, carbon…. Next, experimental and finite element vibration analyses were carried out on the composites with and without an interleaved natural viscoelastic layer. A good agreement between the two methods was obtained. It has been shown that the viscoelastic layer plays a major role in damping because it has a high level of energy dissipation. Therefore, it improves with a significant way the modal properties of the composite. Finally, nonlinear resonance tests were performed on the composites. It has been shown that the viscoelastic layer generates a nonlinear behaviour in the material. The linear and nonlinear, elastic and dissipative parameters have been calculated to deduce finally that nonlinear parameters are more sensitive to heterogeneities than those derived from linear vibration tests
Lutsen, Laurent. „Polycarbosilanes fonctionnels précurseurs de céramiques. Activation par des complexes de métaux de transition“. Montpellier 2, 1994. http://www.theses.fr/1994MON20198.
Der volle Inhalt der QuelleSexton, Alexane. „Développement de films polymères fonctionnels à propriétés de transport de gaz et d’eau contrôlées pour les applications liées au diagnostic médical“. Electronic Thesis or Diss., Lyon 1, 2023. http://www.theses.fr/2023LYO10071.
Der volle Inhalt der QuelleThe control of the transport mechanism for small molecules such as O2, CO2 and H2O is a crucial parameter for medical diagnosis devices. Currently, poly(4-methyl-1-pentene) (PMP) is used for applications which require high gas/water selectivity and transparency of the material. In the context of alternative materials, random polypropylene-ethylene copolymers were selected due to their non-polar structure. In this work, different routes have been developed to increase O2 and CO2 transport properties of PP-PE matrices prepared by melt process: the introduction of zeolite porous fillers or/and plasticizer (dioctyle sebacate) adding. The influence of the nature and quantity of each additive on morphology, polymer chain mobility, gas and water permeability as well as mechanical and optical properties were investigated. Moreover, the detailed characterization of the developed materials allowed the establishment of the structure-functional properties relations
Dumontet, Hélène. „Homogénéisation et effets de bords dans les matériaux composites“. Paris 6, 1990. http://www.theses.fr/1990PA066121.
Der volle Inhalt der QuelleMtibaa, Mohamed. „Οptimisatiοn de cοuplage Ρrοcédé/Ρrοpriétés/Fiabilité des Structures en Μatériaux Cοmpοsites Fοnctiοnnels“. Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMLH03.
Der volle Inhalt der QuelleThis research focuses on the challenges and interactions between the manufacturing processes (Resin Transfer Molding ‘RTM’ and Compression Resin Transfer Molding ‘CRTM’), the mechanical properties, and the reliability of composite material structures; more specifically the functional composites. A number of numerical models have been developed for simulating the suspension (resin + particles) impregnation through the fibrous medium (fibers) in the RTM and CRTM processes. These models are validated by comparing their results with experimental, semi-analytical, and analytical ones from the literature. A parametric study is carried out to demonstrate the impact of various process parameters on particles’ distribution in the final composite. Moreover, a comparison between the injection and compression modes is done. The results of this part show that the distribution of particles in the final part depends on the initial concentration, the distance travelled, and the initial fibers’ volume fraction. However, it is independent of the parameters values of injection and compression. It is also observed that the CRTM process with imposed pressure injection and imposed force compression represents the most favorable scenario for producing composite parts.For the purpose of controlling the final particles’ distribution in the composite material, manufactured by the RTM process, two key steps have been identified. The first step consists in a sensitivity analysis that examines three parameters: the temporal evolution of the initial injected particles’ concentration, the injection pressure field and the initial fibers’ porosity. The conclusions indicate a minimal impact of the initial porosity and the injection pressure field; while the evolution of the initial concentration of the injected particles has a dominant effect. In a second step, an optimization algorithm is implemented in the numerical model of the RTM process. It is used to determine the optimal configuration of the initial injected particles’ concentration’s evolution; in order to approximate the particles’ distribution in the final composite to the desired profiles. The obtained results from the genetic algorithm provide a very satisfactory control of this distribution. To complete this section, a model, estimating the mechanical properties of the manufactured part, is developed. It is found that there is a positive correlation between the particles’ fraction and certain mechanical properties, namely the elastic modulus E11 and E22, and the shear modulus G12 and G23. Nevertheless, the Poisson’s ratio (Nu12) is inversely proportional to the particles’ fraction. Also, the shear module G12 is the most significantly influenced by this fraction.Following this, the control of the mechanical properties of the composite parts, manufactured by the CRTM process, is targeted, and compared to the results of the RTM process. The conclusions reveal that the RTM process offers a better control of these properties. Whereas, the CRTM process improves considerably the mechanical properties of the parts due to its compression phase, which increases the fibers’ volume fraction and consequently enhances these properties.Finally, a static analysis is conducted based on the developed numerical model that uses the finite element method (Ansys APDL). This model is combined with those of the CRTM process and the mechanical properties calculation. An optimization algorithm is integrated in our global model to adapt the mechanical properties of the composite part according to the configuration (cantilever or simply supported) and the load distribution. Moreover, it minimizes the composite part’s weight and ensures the respect of the predetermined mechanical constraints such as the maximum deformation limit. The obtained results correspond perfectly to these objectives
Bouchard, Jonas. „Développement de nouvelles fibres thermostables fonctionnelles chargées en nanotubes de carbone pour des matériaux composites structuraux dans des applications aéronautiques et ferroviaires“. Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10052/document.
Der volle Inhalt der QuelleThis study falls within the framework of the European project IMS&CPS (Innovative Material Synergies & Composite Processing Strategies) and aims at developing new carbon-nanotubes-based thermostable polyethersulfone (PES) fibres. The main goal of this project is the alignment, orientation and integration of carbon nanotubes (CNT) in structural composite materials in order to obtain improved mechanical, thermal and electrical properties, for shielding against electromagnetic interference (EMI) and protection against lightning strike. Using CNT as conductive fillers allows the improvement of electrical conduction inside the fibres and then in the composites by the fibres’ dissolution and the CNT migration in the epoxy composite matrix. A first part focuses on the conductibility and the fire behaviour of the nanocomposites PES/CNT. In a second part, melt and wet spinning were studied as methods for producing nanocomposite fibres. To process PES/CNT by melt spinning it was necessary to add a plasticizer and adapt the heating panels, and this allowed PES melt-spun fibres containing up to 1.5 wt. % CNT to be obtained. CNT pre-orientation and alignment in the production axis of the fibres was also noticed. Then, a weaving process permitted CNT orientation in different directions. Using the wet spinning process, a higher CNT content (2 wt. %) was incorporated in the PES fibres. An electrical percolation threshold of around 1 wt. % CNT incorporated in the PES wet-spun fibres was reached. In both spinning methods, a correlation between processing, morphologies, mechanical and electrical properties of the elaborated fibres was established. The evolution of the fibres’ morphologies and electrical properties after their dissolution in epoxy resins is also mentioned and reveals a significant improvement of their electrical conductivity in the composite matrix
CAMAR-EDDINE, Mohamed. „Fermeture des fonctionnelles de diffusion et de l'élasticité linéaire pour la topologie de la Mosco-convergence“. Phd thesis, Université du Sud Toulon Var, 2002. http://tel.archives-ouvertes.fr/tel-00006576.
Der volle Inhalt der QuelleNowakowski, Pawel. „Systèmes micro-nano-structurés et couches minces multifonctionnels, à base de dioxyde de ruthénium : élaborations et propriétés catalytiques et électriques“. Phd thesis, Université du Sud Toulon Var, 2008. http://tel.archives-ouvertes.fr/tel-00343499.
Der volle Inhalt der QuelleNait-Ali, Azdine. „Matériaux aléatoirement renforcés de type Texsol : modélisation variationnelle par homogénéisation stochastique“. Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2012. http://tel.archives-ouvertes.fr/tel-00762254.
Der volle Inhalt der QuelleCrisafulli, Daniela. „Advanced modelling of multilayered composites and functionally graded structures by means of Unified Formulation“. Thesis, Paris 10, 2013. http://www.theses.fr/2013PA100055/document.
Der volle Inhalt der QuelleMost of the engineering problems of the last two centuries have been solved thanks to structural models for both beams, and for plates and shells. Classical theories, such as Euler-Bernoulli, Navier and De Saint-Venant for beams, and Kirchhoff-Love and Mindlin- Reissner for plates and shells, permitted to reduce the generic 3-D problem, in onedimensional one for beams and two-dimensional for shells and plates. Refined higher order theories have been proposed in the course of time, as the classical models do not consent to obtain a complete stress/strain field. Carrera Unified Formulation (UF) has been proposed during the last decade, and allows to develop a large number of structural theories with a variable number of main unknowns by means of a compact notation and referring to few fundamental nuclei. This Unified Formulation allows to derive straightforwardly higher-order structural models, for beams, plates and shells. In this framework, this thesis aims to extend the formulation for the analysis of Functionally Graded structures, introducing also the thermo-mechanical problem, in the case of functionally graded beams. Following the Unified Formulation, the generic displacements variables are written in terms of a base functions, which multiplies the unknowns. In the second part of the thesis, new bases functions for shells modelling, accounting for trigonometric approximation of the displacements variables, are considered
Tiar, Mohamed Amine. „Éléments finis spéciaux pour l’analyse linéaire et non-linéaire géométrique des structures composites à renforts fibreux“. Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2345/document.
Der volle Inhalt der QuelleNumerical modeling of composite materials and structures with complex geometry of fiber reinforcement, such as stitched composites, constitutes a major research axis in order to correctly predict their mechanical behavior. Within this context, this study focuses on the development of new linear and nonlinear specific finite elements based on a multiscale numerical approach, called the Projected Fiber Approach (PFA). This numerical approach has the advantage of taking into account the presence of fi bers, long or short and distributed randomly or specifically, within a matrix space without discretizing them. Consequently, the obtained system of equations size is equivalent to that without reinforcement (matrix), which considerably reduces the computational cost. To analyze the linear and geometrically nonlinear behaviors of composite structures, two membrane finite elements, named PFT3 and PFQ4, and a 3D solid finite element, named PFH8, were developed and implemented into the commercial finite element code ABAQUS via the user element subroutine (UEL). Several numerical linear and nonlinear tests are considered to assess the accuracy and efficiency of the proposed composite finite elements, and the obtained results are globally in good agreement with the reference solutions. Moreover, the major interest of the PFA approach is particularly emphasized by studying two 3D complex reinforced composite structures: a stitched sandwich plate and a hollow core sandwich plate reinforced by "8" shape fibers
Trejo, O'Reilly José Antonio. „Synthèse d'agents de couplage, réactions de greffage en surface de fibres cellulosiques et propriétés d'interface fibres-matrices dans des matériaux composites à base de polystyrène“. Grenoble INPG, 1997. http://www.theses.fr/1997INPG0019.
Der volle Inhalt der QuelleClemenson-Simon, Sandra. „Nanostructuration de membranes polymère-métal pour applications fonctionnelles“. Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10070.
Der volle Inhalt der QuelleThis work deals with the study of the nanostructuration of polymer/metal membranes, realised by in situ generation. We specified the chemical and physico-chemical parameters influencing the nanostructure of polyvinyl alcohol and polyetherimide matrix films nanostructured by silver and palladium nanoparticles, thanks to different precursors and different preparation solvents. We showed the influence of the nanostructuration processes (thermal, under irradiation and chemical) on the morphology and on the functional properties of the nanocomposite films. On the whole, the nanostructuration conditions had a high impact both on the generated nanoparticles sizes and their organisation in the film thickness. The morphology’s impact was then evaluated on the functional properties, i.e. in our case on the mechanical properties and on the gas transport properties. The analysis of these two types of properties allowed us to specify the dispersion effects and the role of the nanoparticles/polymer interfaces. We also showed that the transport in the polymer/palladium nanocomposite films could be analysed and construed as active transport
Chabert, France. „Elaboration de membranes pour piles a combustible par extrusion“. Phd thesis, 2004. http://tel.archives-ouvertes.fr/tel-00442970.
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