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Haghdan, Shayesteh. "Energy absorbing ability of wood/polyester composite laminates." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54552.
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Currently used energy absorbers in transportation industries are made of synthetic fiber/polymer composites as an alternative to their metal counterparts. These composites are stiff and strong but are somewhat brittle when subjected to impact load which limits their application when high energy absorbing ability is required. Wood, in contrast, has a high stiffness and strength to weight ratio and exhibits a higher deflection before failure. Despite the extensive research on the mechanical properties of synthetic fiber/polymer composites few researches are available on the effects of wood composite configuration and densification and its lamination set-up on its impact and compressive properties. This research focused on the use of wood in the form of thin veneer to reinforce polyester and composites of them were fabricated using hand lay-up and compression molding, in different thicknesses. Various wood configurations were used to create unidirectional, cross-ply, and woven mats. The effects of each mat configuration on the impact properties of wood/polyester composites and the lamination and curing processes were investigated and discussed. The gap of knowledge on the wettability of wood to the polyester resin was informed in this dissertation using contact angle measurements and roughness tests. Energy absorbing behavior and dominant fracture mechanisms of wood/polyester laminates subjected to quasi-static compression and shear loading were examined and the results were compared with the lab-made glass fiber/polyester composites. Findings of this study demonstrated that the effect of wood configuration on the impact properties of the polyester composites was significant. Wood densification improved the impact performance of composites but this improvement was not statistically significant. It was found that wood composites had an impact energy equivalent to that of glass fiber laminates.<br>Forestry, Faculty of<br>Graduate
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Fehervari, Sylvie. "Propriétés mécaniques d'une résine polyester, influence d'une pression de confinement : application à un composite polyéthylène-polyester." Lille 1, 1995. http://www.theses.fr/1995LIL10001.
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La plasticité de la résine polyester a été évaluée en traction et en compression à vitesse de déformation constante et en fluage. L'analyse thermodynamique de la déformation à vitesse de déformation imposée indique que la barrière locale d'énergie <go à la propagation des microzones cisaillées est la même en traction et en compression. En outre, la différence des volumes d'activation dans ces deux modes de sollicitation traduit une différence de contrainte d'écoulement. Les cinétiques de fluage en traction et en compression sont exprimées par une loi de type =atm. Nous mettons en évidence le rôle joue par les mobilités moléculaires et le vieillissement physique sur le comportement en fluage du polyester. Comme pour les essais a vitesse de déformation constante, une différence de comportement entre traction et compression est observée. Des essais complémentaires de compression sous pression de confinement conduisent à rendre compte de l'ensemble de nos résultats expérimentaux par un critère de plasticité de Coulomb. La connaissance de la plasticité de réseau polyester permet, dans le cas des composites à fibres de polyéthylène et matrice polyester d'identifier les contributions respectives de la matrice et de renfort dans la réponse mécanique globale du matériau.
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Davallo, Mehran. "Mechanical behaviour of glass-polyester composite formed by resin transfer moulding." Thesis, Manchester Metropolitan University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301045.
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DESLANDES, NATHALIE. "Etude des interactions de solvants avec un materiau composite a matrice polyester." Paris, ENSAM, 1996. http://www.theses.fr/1996ENAM0018.
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Le bmc (bulk molding compound) est un materiau composite injecte, a matrice polyester-styrene renforcee par des fibres de verre courtes et chargee en carbonate de calcium. Il est utilise dans l'industrie automobile pour la fabrication de panneaux de carrosserie. Lors de la mise en peinture, il apparait parfois des defauts d'aspect constitues par des macropores de quelques centaines de microns de diametre. Notre etude porte sur la comprehension du phenomene et les interactions entre le materiau composite et les solvants contenus dans les peintures. La compensation du retrait de la matrice est assuree par la creation de microvides/microfissures dont la taille est de l'ordre du micron. Contrairement a la composition globale du materiau, la taille et la distribution des microvides varient en fonction de la longueur d'ecoulement. Les concentrations des microvides et des macropores varient en sens oppose. Nous avons trace des cartes bidimensionnelles des parametres de solubilite permettant de predire l'activite d'un solvant quelconque envers le materiau composite
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Afzal, Muhammad Ali. "Development of a coaxial composite fiber." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH0599/document.
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Les filaments composites cœur/peau ont été développés dans le but de proposer des capteurs et de effecteurs textiles pour des applications « smart textiles ». Le filage des filaments a été effectué avec une technique de type extrudeuse à piston. Le travail a porté sur la modification d’une machine de filage par fusion, de la caractérisation de polymères, de la caractérisation des filaments développés et de l’optimisation des techniques d’obtention des filaments. La conception du procédé ainsi que son optimisation ont été effectués avec du PET. La modification de la machine a consisté à concevoir les filières, modifier le piston et à introduire un canal d’alimentation sous forme de tube en inox pour sécuriser le passage du filament métallique d’âme dans le four. Ainsi, 10 filières différentes et trois pistons ont été conçus en se fondant sur les règles industrielles puis leurs performances ont été optimisées. Les polymères ont été caractérisés par DSC, par rhéologie et par techniques analytiques. Ces résultats ont montré la forte influence de la température en particulier une forte réduction de la cristallinité du filament composite. L’optimisation des paramètres d’extrusion a pris en compte la vitesse du piston, la vitesse de bobinage, les modifications de la machine dont le nombre de trous des filières, la position du tube dans la filière, les dimensions internes du tube, le diamètre de sortie de la filière. Il a été montré que la conception de la filière a une influence significative sur la forme des filaments obtenus ainsi que sur la concentricité de l’âme. Les propriétés physiques, morphologiques, tribologiques et mécaniques des filaments ont été mesurés. Ainsi, les filaments ont des diamètres compris entre 350 et 500 µm et peuvent être de formes elliptique, triangulaire, rectangulaire ou circulaire et les meilleures propriétés mécaniques sont obtenues avec les filaments le plus réguliers tandis que les filaments irréguliers présentent un coefficient de frottement plus important. Les résultats concernant la rigidité en flexion se sont avérés peu fiables. A partir des paramètres optimisés, un filament composite de polymère ferroélectrique (PVDF 70%-TrFE 30%) avec une âme cuivre a été filé et a montré de parfaites caractéristiques de forme et de concentricité. Ce filament composite peut maintenant être utilisé pour développer des capteurs et des effecteurs, des transmetteurs de signaux, des boucliers électromagnétiques et de l’électronique intégrable dans les vêtements<br>A coaxial composite fiber has been developed for the intended application in textile based sensors, actuators and eletric signal transmissions in wearable textile products. The work focuses on melt extrusion machine modification, characterization of polymers, characterization of developed filaments and optimization techniques for obtaining required results. Melt extrusion machine has been used having piston based mechanism. The process design and optimization was done using polyester polymer. The machine modification includes design of spinnert, piston end modification and introduction of separate feeding channel for core filament in the oven. A number of 10 spinnerets designs were developed according to industrial die design rules and optimized for their performance. The piston end designs developed were 3 in number. A stainless steel tube has been introduced into the oven for a separate secure passage of core filament. The polymer characterization was done by thermal, rheological and analytical techniques. The obtained results exhibited thermal attibutes of the polymer and showed reduction in degree of crystallanity in composite filament. The optimization of extrusion parameters including piston speed, winding speed ; and modifications in machine which includes design parameters of number of holes, tube position, tube internal diameter and spinneret exit diameter were done. It was observed that design parameters have significant effect on cross-sectional shape, eccentricity of core and morphology of filament. The characterization of composite filament has been carried out by physical, morphological, mechanical, tribology and bending techniques. The composite filaments developed were in range of 350-500 µm diameter. The filaments developed have elliptical, triangular, rectangular and circular shapes. The regular filaments showed higher tenacity and breaking strength than irregular shaped filaments. The frictional coefficient values were found higher for irregular shapes. Bending stiffness results obtained were not reliable for irregular cross-sectional shapes. The optimized parameters wers used to develop composite filament using ferroelectric polymer (PVDF-TrFE) having 70 :30 ratio copolymer. The developed filament was very regular in shape with good eccentricity of core. The developed Cu/PVDF-TrFE core/sheath filament can be used for development of sensors and actuators. The Cu/Polyester core/sheath filament can be used for electrical signal transmission lines in wearable electronic textiles and for development of electromagnetic shielding effectiveness fabrics
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Kayatin, Matthew Jay Davis Virginia A. "Rheology, structure, and stability of carbon nanotube-unstaturated polyester resin dispersions." Auburn, Ala, 2008. http://hdl.handle.net/10415/1421.
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Tsoi, Marvin S. "Modeling of thermal properties of fiber glass polyester resin composite under thermal degradation condition." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4711.
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Composites, though used in a variety of applications from chairs and office supplies to structures of U.S. Navy ships and aircrafts, are not all designed to hold up to extreme heat flux and high temperature. Fiber-reinforced polymeric composites (FRPC) have been proven to provide the much needed physical and mechanical properties under fire exposure. FRPC notable features are its combination of high specific tensile strength, low weight, along with good corrosion and fatigue resistance. However FRPC are susceptible to thermal degradation and decomposition, which yields flammable gas, and are thus highly combustible. This property restricts polymeric material usage. This study developed a numerical model that simulated the degradation rate and temperature profiles of a fiber-reinforced polyester resin composite exposed to a constant heat flux and hydrocarbon fire in a cone calorimeter. A numerical model is an essential tool because it gives the composite designer the ability to predict results in a time and cost efficient manner. The goal of this thesis is to develop a numerical model to simulate a zonal-layer polyester resin and fiber-glass mat composite and then validate the model with experimental results from a cone calorimeter. By inputting the thermal properties of the layered composite of alternating polymer and polymer-infused glass fiber mat layers, the numerical model is one step closer to representing the experimental data from the cone calorimeter test. The final results are achieved through adding a simulated heat flux from the pilot ignition of the degraded gas of the polyester resin. The results can be coupled into a mechanical model, which may be separately constructed for future study on the mechanical strength of composites under fire conditions.<br>ID: 030646184; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.M.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 53-54).<br>M.S.M.E.<br>Masters<br>Mechanical and Aerospace Engineering<br>Engineering and Computer Science<br>Mechanical Engineering; Thermo-Fluids Track
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Smith, Kevin Jackson. "Compression creep of a pultruded E-glass/polyester composite at elevated service temperatures." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7195.
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This thesis presents the results of an experimental investigation into the behavior
of a pultruded E-glass/polyester fiber reinforced polymer (FRP) composite under
sustained loads at elevated temperatures in the range of those that might be seen in
service. This investigation involved compression creep tests of material coupons
performed at a constant stress level of 33% of ultimate strength and three temperatures
levels; 23.3°C (74°F), 37.7°F (100°F), and 54.4°C (130°F). The results of these
experiments were used in conjunction with the Findley power law and the Time-
Temperature Superposition Principle (TTSP) to formulate a predictive curve for the longterm
creep behavior of these pultruded sections. Further experiments were performed to
investigate the effects of thermal cycles in order to better simulate service conditions.
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Riopel, Sébastien. "Étude expérimentale de la cuisson d'un composite unidirectionnel verre/polyester de grande épaisseur." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ53598.pdf.
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Speake, Stephen David. "Prediction of the rate of degradation of a polyester glass composite by water." Thesis, Kingston University, 1986. http://eprints.kingston.ac.uk/20509/.
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Jelidi, Ahmed. "Conception d'un matériau composite à matrice cimentaire renforcée par des fibres de polyester." Lyon, INSA, 1991. http://www.theses.fr/1991ISAL0006.
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Dans le contexte de la substitution des fibres d'amiante dans le ciment par fibres synthétiques, nous avons étudié les possibilités de l'utilisation des fibres de Polyester dont le coût est très concurrentiel. Dans l'étude du comportement mécanique du composite ciment Portland artificiel-fibres longues de polyester, nous avons constaté une évolution décroissante de l'indice de ténacité et une mauvaise durabilité. L'approche physico-chimique (MEB, SIRTF, DRX, Micro-analyse, Corrosion) nous a permis d'expliquer le mécanisme de dégradation des fibres de Polyester dans le ciment Portland hydraté : diminutions du diamètre et de la masse dues aux réactions de déploymérisation de la chaîne du polyester par les alcalins existants dans la solution interstitielle du ciment (en particulier la potasse) · détérioration surfacique due à des entailles occasionnées par des cristaux tranchants (essentiellement des hexagones de chaux). Pour pallier cette dégradation, nous avons axé notre recherche sur la formulation d'une matrice cimentaire à ajouts pouzzolaniques. Nous avons abouti à une matrice « ciment, métakaolin, montmorillonite calcinée et Chlorure de calcium » " qui permet d'éliminer les causes de dégradation et de garantir la durabilité du composite. La protection des fibres de Polyester dans la matrice cimentaire est ainsi assurée<br>In the purpose of substitute asbestos fibres by synthetic fibres, we have studied the possibility of using polyester fibres wich are low cost. The investigation of the mechanical behaviour of the ployester reinforced concrete has led us to note the decrease of the toughness index and a bad durability. The physico-chemical approach (SEM, IRS, XRD, ADAX, corrosion) has allowed us to explain the degradation mechanisms of polyester fibres in hydrated Portland cement : the diameter and mass decrease is due to polyester chain depolymerization reactions which the alkalis existing in the pore solution (potash particularly) ; the surfacic deterioration is due to notches causes by cutting crystals(lime crystals). To prevent this degradation we have centred our research on the development of a pozzolanic blended. A matrix composed of « cement, metakaolin, burnt montmorillonite and calcium chloride » permits to climinate degradation causes and guarantee the composite durability. The protection of polyester fibres in the cementition matrix is then insured
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Wood, Arran R. "Investigation of interfacial properties in a composite of nanomodified polyester resin and glass fibre." Thesis, University of Surrey, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511118.
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Gouanvé, Fabrice. "Comportement à l’eau d’un composite à matrice polyester insaturé renforcée par des fibres de lin." Rouen, 2005. http://www.theses.fr/2005ROUES006.
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Les résines polyester sont des polymères denses habituellement utilisés comme matrice dans de nombreuses applications industrielles. Elles ont pour avantage leurs excellentes propriétés mécaniques et chimiques, leur bonne résistance au vieillissement et d’un point de vue économique, un faible prix de revient. En outre, on peut les renforcer par des fibres et obtenir ainsi un matériau composite dont les propriétés mécaniques dépendent étroitement de la nature, la taille, la dispersion des fibres. Le plus souvent, on utilise des fibres synthétiques telles que les fibres de verre ou de carbone. Cependant depuis quelques années, on tend à leur substituer des fibres végétales. Nous avons étudié dans ce mémoire le comportement perméamétrique et mécanique d'un matériau composite constitué d’une matrice polyester insaturé renforcé par des fibres de lin. Celles-ci ont été retenues pour leur faible coût, leur densité réduite et surtout leurs bonnes propriétés mécaniques. Par contre leur forte sensibilité à l’eau peut conduire un vieillissement hydrolytique prématuré. L’application de fibres naturelles comme renfort dans les matériaux composites implique une faible sensibilité à l’humidité ainsi qu’une forte adhésion entre les fibres et la matrice synthétique. Différents traitements peuvent être réalisés afin d’optimiser l’interface. Dans notre étude, deux traitements ont été réalisés sur les non-tissés de fibres dans le but d’une part, d’augmenter leur résistance à l’eau, par le biais d’un traitement autoclave à la vapeur d’eau et d’autre part d’améliorer leur adhésion avec la matrice à l’aide d’un traitement par plasma froid. L’efficacité des traitements a été mise en évidence par des mesures de perméation à l’eau et des tests de traction. Les résultats de perméation montrent que l’introduction du renfort conduit à une augmentation du coefficient de perméabilité ainsi que la diffusivité comparativement à la résine seule. Le traitement plasma conduit à une baisse de la perméabilité du composite qui s’explique par une baisse de la diffusivité. La résistance à l’eau des fibres a augmenté après traitement autoclave. Les tests mécaniques ont montré une augmentation du module d’élasticité, E, après introduction des fibres. De même les composites renforcés par des fibres traitées plasma ont un module d’élasticité supérieur aux à ceux renforcés par des fibres de lin natives. Des images de microscopie électroniques à balayage confirment l’amélioration de l’adhésion après traitement plasma<br>Natural fibers have been used as structural materials since prehistoric times. Environmental concerns such as global warming, energy consumption, and the desire to obtain products from renewable sources has led to a resurgence of interest in plant-derived products. Plant fibers are very attractive for composite materials because the fibers have some interesting characteristics. For example, they are cost-effective, renewable, and available in high quantity, have low fossil-fuel energy requirements and can offer good mechanical properties. Natural fibers as flax have attracted attention because of their low cost compared with synthetics fibers such as glass, carbon. The application of flax fibers as reinforcements in composite materials requires a strong adhesion between the fiber and the synthetic matrix. The properties of the fiber-matrix interface are of great importance for the macroscopic mechanical properties. Physical and chemical treatments can be used to optimize this interface. In this study, an autoclave treatment and a cold plasma treatment have been carried out on the reinforcing fibers in order to increase moisture resistance and improve adhesion with the matrix respectively. The analysis of the permeation and mechanical results has shown that plasma treatment improves fiber/matrix adhesion while autoclave treatment reduces water solubility in the fibers. For reinforced composites, therefore, autoclave treatment is more efficient in terms of water permeability and plasma treatment gives better stiffness in terms of mechanical properties. This phenomenon was highlighted by SEM micrographs
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Janeček, Pavel. "Vliv povrchových úprav skleněných vláken na mechanickou odezvu GF/polyester kompozitu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216224.
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The diploma thesis is aimed at an influence of surface modifications of fibrous reinforcements on mechanical properties at the fiber-matrix interface in fiber reinforced composites. Glass fibers were used as reinforcements and polyester resin was the matrix. The sample of composite consisted of polymer matrix in a form of cylindrical body placed on bundle of glass fibers. The design of the sample was constructed with respect to results of Finite Element Analysis (FEA). The tensile test using a materials testing machine (Zwick) was employed to evaluate adhesion at the fiber-matrix interface. Untreated glass fibers, fibers with commercial sizing, and fibers modified by deposition of plasma polymer film using Plasma-Enhanced Chemical Vapor Deposition (PECVD) at different deposition conditions were used for fabrication of composite samples. The fibers and composite samples were analyzed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM).
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Kiehl, Julien. "Compréhension et optimisation de la dispersion du carbonate de calcium dans une résine polyester insaturée." Thesis, Mulhouse, 2012. http://www.theses.fr/2012MULH4087.
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L’objectif de ce travail est d’adapter une formulation dispersante mise au point par la société Mäder à la dispersion de carbonate de calcium (CaCO3) dans une résine polyester insaturée (UP). Le carbonate de calcium est utilisé en tant que charge dans les matériaux composites à matrice thermodurcissable et en particulier dans les SMC (Sheet Molding Compound). Le rôle de cette formulation est de diminuer les viscosités de résines UP fortement chargées tout en conservant voire en améliorant les propriétés mécaniques des composites formés par un renforcement de l’interface charge / matrice. Trois grands axes ont été développés au cours de ce travail : - le comportement rhéologique d’un mélange CaCO3/résine UP a été déterminé et la formulation dispersante a été optimisée ; - la nature des interactions entre les différents constituants de la formulation dispersante et la surface du CaCO3 a été mise en évidence ; - de nouveaux polymères permettant une dispersion plus efficace de la charge dans la résine ont été synthétisés. Le mélange CaCO3 / résine UP présente un comportement rhéologique complexe. L’optimisation de la formulation dispersante a permis d’augmenter de plusieurs pourcents le taux de charge tout en conservant des viscosités inférieures à celle autorisée par le procédé industriel. L’étude des interactions des constituants de la formulation avec le carbonate de calcium a permis de déterminer les fonctions les plus réactives et de comprendre leur interaction avec la surface de la charge. La synthèse de nouveaux dispersants a également été effectuée. Ces derniers ont ensuite été testés dans l’application et ont montré une efficacité à disperser le CaCO3 dans la résine UP<br>The aim of this study is to adapt a dispersive formulation developed by the Mäder group to the dispersion of calcium carbonate (CaCO3) in an unsaturated polyester resin (UP). The CaCO3 is commonly used as filler in the domain of composites especially for Sheet Molding Compound (SMC). This dispersive formulation is able to decrease the viscosity of UP resin containing a high amount of filler. In addition, the mechanical properties of composites could be increased by reinforcing the filler / matrix interface. Three main ways have been studied: - characterization of the rheological behavior of CaCO3 / polyester blends and optimization of the dispersive formulation ; - determination of the interactions between the dispersive formulation components and the CaCO3 surface ; - synthesis of new polymers in order to improve the CaCO3 dispersion in an organic matrix. A complex rheological behavior has been observed for CaCO3 / polyester blends. The dispersive formulation improvement led to an increasing of the filler percentage by keeping the viscosity under the industrial limit. The most reactive functions with the CaCO3 surface have been identified by studying the interactions between the dispersive formulation components and the CaCO3 surface. New dispersing agents have been synthesized. Their efficiency has been demonstrated for the dispersion of CaCO3 in a UP resin
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Graham, Zachary. "Numerical simulation of fracture of a nano-paper coated e-glass/polyester composite with thermal damage." Honors in the Major Thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/849.
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Aerospace research for next-generation travel increasingly focuses on the use of advanced composites to reduce weight and cost while retaining strength. One subset of materials with great potential is based on the combination of resin matrix and glass-fiber reinforcement. This research explores the application of a candidate nanopaper coating with a given composite. Prior research applied a set of given heat fluxes to the top surface of the composite for a set of given periods of time, and subsequently performed a 3-point flexural test to determine the elastic modulus for both the coated and uncoated composite for all of the combinations of heat flux and time. A finite element (FE) model is developed using the ANSYS general purpose finite element analysis (FEA) software that models the degradation in strength/stiffness properties based on heating condition and with the goal of predicting cracking using the element death feature in ANSYS. This thesis describes the prior research suggesting both the need for and novelty of this model, and the procedures used to form the model. The loading conditions of the 3-point flexural test are replicated, and four measures of accuracy are developed based on the force versus displacement curve of the test and the FE model. It is envisioned that continuum-level models developed as a part of these research be applied for design of next-generation space components These measurements are used to verify the FE model, and this model is then employed to extrapolate beyond the context of experimental conditions.<br>B.S.M.E.<br>Bachelors<br>Mechanical, Material and Aerospace Engineering<br>Engineering and Computer Science
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Jesson, David Alan. "The interaction of nano-composite particles with a polyester resin and the effect on mechanical properties." Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/808438/.
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The effect of various organically modified silica (ormosil) nano-particle additions on the mechanical properties of a polyester resin has been investigated. For materials produced on such a fine scale, surface properties are known to dominate the manner in which they behave. This thesis presents results from two complementary areas of study: surface analysis and mechanical testing. The surface properties of the nano-particles and the interactions of the nano-particles with a polyester and adsorbed water have been investigated. These analyses have led to the development of a model which shows that the small organic groups grafted to the silica surface (methyl, ethyl and vinyl) are able to pack comparatively densely at the surface, effectively forming a continuous monolayer. This layer is sufficiently thick to prevent interaction of retained silanol groups with the polyester resin. When the silica is modified with phenyl functionality, however, the larger size leads to a more dispersed organic coverage that cannot be considered as a complete monolayer. Hence this layer reduces, but will not completely prevent interaction of the matrix with retained silanols of the silica. The particles have been dispersed in a polyester resin successfully. The dispersion process is an important step in producing viable nano-composites. Mechanical testing of such nano-composites has found a significant improvement in the toughness properties of the phenyl ormosil modified polyester, compared with the unmodified resin, whilst the other modified polyesters show smaller improvements. When considered with the surface analysis investigation, it is argued that the improvement is a result of a reduction of the strength of the interface (with reference to a commercial nano-silica) between the particles and the matrix. The phenyl ormosil is more strongly bonded than the other ormosils. Whilst these other ormosils are able to contribute to toughness through a crack pinning mechanism, the phenyl ormosil absorbs energy through debonding and promotes plastic deformation in the matrix, around and between particles, mechanisms which lead to a greater toughness enhancement.
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Ma, Hongming. "Structure-property relationships in copolyester fibers and composite fibers." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-04112004-150623/unrestricted/Ma%5FHongming%5F200405%5Fphd.pdf.
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Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2004.<br>Collard, David, Committee Co-Chair ; Schiraldi, David, Committee Member ; Liotta, Charles, Committee Member ; Weck, Marcus, Committee Member ; Srinivasarao, Mohan, Committee Member ; Kumar, Satish, Committee Co-Chair. Vita. Includes bibliographical references.
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Bennett, Evan A. "Influence of Creep on the Stability of Pultruded E-Glass/Polyester Composite Columns at Elevated Service Temperatures." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7187.
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This study is an experimental investigation pertaining to the creep behavior of slender pultruded fiber-reinforced polymeric (FRP) columns subjected to sustained concentric axial loading at elevated service temperatures. Six creep tests were performed on columns having a slenderness ratio of 49 at different combinations of axial load and temperature for a duration of at least 1,000 hours. The axial loads used represented 33%, 67%, and 90% of the critical buckling load for the column selected. For each load level, one test was performed at 22.8℃ (73℉) and one test was performed at 65.5℃ (150℉) Knife-edge end supports were utilized to simulate pinned-pinned boundary conditions. Midheight lateral deflection and axial shortening were recorded incrementally for the duration of the testing. Following termination of the creep tests, the columns were allowed to recover and tested for buckling strength. A semi-empirical model for long-term behavior of concentrically loaded FRP columns at elevated service temperatures is proposed based on experimental results.
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Saulnier, Florence. "Influence de traitements physico-chimiques des renforts sur le comportement mécanique des composites à base de co-produits de bois." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00959532.
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Cette thèse porte sur le traitement de la farine de bois et son utilisation comme renforts de composites à matrice polymère. En effet, l'incompatibilité entre le bois, hydrophile, et les polymères, généralement hydrophobes, est la principale difficulté de mise en oeuvre des composites bois-polymère. Un traitement des renforts bois est alors nécessaire pour améliorer les propriétés mécaniques et hygroscopiques des composites. Un traitement par fluoration directe est ici proposé pour diminuer le caractère hydrophile du bois et augmenter son adhésion avec la matrice polymère. Après une phase de développement et de réglage du traitement, une caractérisation physico-chimique de la farine de bois non-traitée ou fluorée a été réalisée afin d'observer l'effet de la fluoration. Le greffage de fluor sur les constituants du bois a été validé, et une diminution du nombre des sites de sorption de l'eau dans le bois a été constatée. Cette réduction a conduit à une diminution de la teneur en eau du bois après fluoration. En outre, la structure physique des particules et le comportement thermique du bois n'ont pas été modifiés par le traitement. Des composites bois-polyester ont été fabriqués par moulage par compression à chaud, avec des renforts non-traités et fluorés. Ceux-ci ont été testés en traction, en flexion, et en fluage afin d'observer l'influence du traitement sur les propriétés mécaniques des composites. Par ailleurs, une caractérisation hygroscopique a également été conduite. Les résultats montrent que la fluoration directe des renforts permet d'améliorer les propriétés mécaniques et hygroscopiques des composites bois-polyester.
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Nenov, Stanislav Stojanov. "Technologie výroby sklolaminátového dílu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318775.
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Diploma thesis is focused on production technology of the glass fibre polyester part. It introduces characteristics of the composite materials and their dividing by the reinfocement geometry, reinforcement dimensions, reinfocement material and matrix materiál. In the final chapters thesis describes production technologies and proces of launching new part from 3D data to data and drawings of the mould including creation of the technological process.
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Cousinet, Sylvain. "Evaluation de nouvelles matrices organiques biosourcées sans styrène pour composites SMC." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0149.
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De par leurs bonnes propriétés mécaniques, leur faible densité, leur faible coût, et leur bel aspect de surface, les composites SMC (Sheet Molding Compound) sont des matériaux de choix pour réaliser des pièces automobiles semi-structurelles. Ces matériaux sont principalement constitués d’une résine polyester (UPR), d’un additif thermoplastique comme agent anti-retrait, de carbonate de calcium comme charge et de fibres de verre coupées comme renfort. Le contexte environnemental et socio-économique actuel encourage les constructeurs automobiles à utiliser des matériaux issus de ressources renouvelables afin de réduire l’utilisation des réserves pétrolières, et de trouver une alternative au styrène (COV, polluant atmosphérique dangereux et potentiellement cancérigène) qui est utilisé comme diluant réactif (DR) dans les UPR. L’objectif de ce travail est de développer une matrice organique biosourcée (UPR et agent anti-retrait) pour composite SMC moulable par le même procédé de mise en forme et présentant le même niveau de performance comparé à l’existant pétrosourcé. La première partie de ce travail est consacrée à l’évaluation de nouveaux diluants réactifs biosourcés (MMA, BDDMA, BDDVE, EDI, IBOMA et LMA) comme substituants du styrène sur la base des contraintes liées au procédé SMC. Les résines sélectionnées ont ensuite été polymérisées et les réseaux obtenus caractérisés. Le mécanisme de copolymérisation a été étudié et a permis de mettre en évidence l’influence de la nature chimique des insaturations et de la fonctionnalité du DR sur les propriétés finales du réseau. De par sa faible viscosité, sa faible volatilité et son point éclair élevé, le BDDMA est un bon candidat pour remplacer le styrène dans les UPR. La partie suivante est consacrée à la caractérisation d’un prépolymère polyester insaturé et de différents agents anti-retrait biosourcés. Des matrices organiques ont été formulées avec différents agents anti-retrait, puis polymérisées et caractérisées. L’influence de la nature et du taux d’agent anti-retrait sur le retrait de polymérisation et les propriétés mécaniques a été évaluée. Des essais sur composites SMC à l’échelle pilote ont été réalisés afin d’étudier les propriétés finales des composites biosourcés. La meilleure compensation du retrait est obtenue pour l’additif de plus faible Tg, c'est-à-dire le polyester saturé biosourcé. Le réseau à base de BDDMA étant très fragile, la suite de ce travail a consisté à réduire la densité de réticulation du réseau en introduisant un monométhacrylate biosourcé dans la formulation (MMA, IBOMA et LMA) afin d’améliorer les propriétés au choc du matériau. Enfin, un nouveau DR biosourcé, le lévulinate de vinyle, a été évalué comme substituant du styrène dans les UPR. Le mécanisme de copolymérisation a été mis en évidence et relié à la structure et aux propriétés finales du réseau<br>Due to their good mechanical properties, low density, low cost and good surface properties, SMC composites (Sheet Molding Compound) are suitable for manufacturing half-structural automotive parts. These materials are mainly based on a unsaturated polyester resin (UPR), thermoplastics as low profile additives, calcium carbonate as filler and chopped glass fibers. Current environmental and socio-economic concerns motivate automotive manufacturers to use bio-based materials in order to reduce the use of crude oil reserves and to find an alternative to styrene (VOC, hazardous air pollutant, potential carcinogen) which is used as reactive diluents (RD) in UPR. The aim of this work was to develop a bio-based organic matrix (UPR and low profile additive) for SMC composites with a similar processability and same level of performances compared to petroleum-based analogs. The first part of this work describes the evaluation of new bio-based reactive diluents (MMA, BDDMA, BDDVE, EDI, IBOMA and LMA) as styrene substituents for UPR, taking into account SMC process requirements. Selected resins were polymerized and the obtained networks characterized. Copolymerization mechanism was studied and allowed to highlight the influence of the chemical nature of unsaturations and the functionality of reactive diluents on network properties. Due to its low viscosity, low volatility and high flashpoint, BDDMA is a good candidate to replace styrene in UPR. Next part was dedicated to the characterization of bio-based unsaturated polyester and low profile additives. Several organic matrices were formulated with different low profile additives, then polymerized and characterized. The influence of the low profile additive nature and content on the polymerization shrinkage and mechanical properties of the material was evaluated. SMC composites were manufactured at the pilot scale and characterized in order to study the final properties of bio-based composites. The best shrinkage control is obtained with low-Tg additive (bio-based saturated polyester). Nevertheless BDDMA-based network is very brittle, so a next step of our work was to introduce a monofunctional methacrylate (MMA, IBOMA and LMA) into the matrix in order to decrease the crosslink density of the network and improve its impact resistance. The influence of the methacrylate nature and content on the structure and mechanical properties of the polyester networks was highlighted. Finally, a new bio-based RD, vinyl levulinate, was evaluated to replace styrene in UPR. Its copolymerization mechanism with UP was studied and related to the structure and mechanical properties of the network
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Xu, Liqun. "Integrated analysis of liquid composite molding (LCM) processes." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1095688597.
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Thesis (Ph. D.)--Ohio State University, 2004.<br>Title from first page of PDF file. Document formatted into pages; contains xix, 245 p.; also includes graphics. Includes bibliographical references (p. 233-245).
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Lemattre, Alexis. "Développement de résines polyester insaturées ignifugées : caractérisation des performances feu/fumées et détermination des mécanismes de décomposition." Thesis, Mulhouse, 2018. http://www.theses.fr/2018MULH2179.
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Depuis des années, les marchés des résines polyester insaturées (UP) et des composites sont en pleine expansion. En effet, grâce à la versatilité de leurs structures chimiques, les résines UP offrent un éventail de propriétés physico-chimiques et mécaniques pour le matériau final. Ces caractéristiques ainsi que leur bon rapport performance / prix expliquent l’engouement des industriels pour leur utilisation dans les composites et « gels coat » dans les domaines du bâtiment et du transport. Cependant, ces résines sont inflammables et présentent donc un risque pour leurs utilisations dans les domaines d’application accueillant des personnes. Les réglementations européennes imposent par conséquent une amélioration des propriétés feu/fumées de ces résines. La norme européenne EN45545-2 entrée en application en 2018 a pour but d’unifier les différentes normes nationales et de diminuer le risque d’incendie dans les transports ferroviaires. Les résines UP halogénées actuellement sur le marché produisent des quantités de fumées opaques et toxiques importantes. Les objectifs de ces travaux ont donc été de synthétiser et/ou d’additiver de nouvelles résines UP non halogénées et fluides possédant une tenue au feu comparable à celle des résines halogénées. La combinaison de résines UP modifiées et de retardateur de flamme (RF) additifs a été étudiée et optimisée. L’utilisation à la fois d’un RF réactif et d’un RF additif possédant un effet de synergie a permis de répondre au cahier de charges défini par le partenaire industriel. Cette résine a permis d’améliorer les performances feu/fumées du matériau composite sans impacter ses propriétés physico-chimiques et mécaniques<br>For many years, unsaturated polyester (UP) resins and composites markets are growing. Indeed, the wide range of UP resins gives a large physico-chemical and mechanical properties to composites. These properties and the good performance / price ratio explain the market growth of these resins in industrial applications like composites or gel coats for transportation and construction. However, UP resin exhibit low flammability and the enhancement of their fire behaviour is needed to meet the legislation and to protect goods and people. Since 2018, the European legislation for fire protection used in railway applications (EN45545-2) has strengthened and been harmonized. Smoke opacity and toxicity are the main issue of halogenated unsaturated polyester resins currently used on this market. The aims of this study were thus to develop and formulate new halogen-free and low viscosity UP resins presenting good flame retardant properties. A synergist mixture of reactive and additive flame retardants (FR) was found to be the solution to substitute brominated UP resins and meet the industrial specifications. Finally, the use of such a resin enables developing flame retardant composites without affecting their physico-chemical and mechanical properties
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Lamy, Yoann. "Nanostructuration de résines polyester insaturé par des copolymères à blocs : application aux composites SMC et BMC." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00812588.
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On s'intéresse dans cette étude au potentiel de copolymères à blocs (BCP) de types PBA-b-P(MMA-co-DMA) et PBA-b-P(BA-co-DMA) en tant qu'additifs multifonctionnels nanostructurant la matrice thermodurcissable polyester insaturé de composites SMC et BMC. La nanostructuration de la résine polyester insaturé (UPR) est assurée par la ségrégation du bloc élastomère poly(acrylate de butyle), ainsi que par la miscibilité du deuxième bloc dans le réseau grâce à la bonne compatibilité des motifs diméthylacrylamide (auto-assemblage). Ces BCP sont tout d'abord étudiés en tant qu'agents renforçants et anti-retrait dans les composites SMC et BMC, en étant substitués et comparés aux additifs anti-retrait conventionnels PVAc et P(MMA-co-S) incorporés traditionnellement afin de compenser le retrait de la résine polyester. Ces additifs nanostructurants sont ensuite évalués en tant qu'agents de mûrissement des compounds SMC. La nanostructuration des BCP dans la résine UP réactive pouvant entrainer une importante augmentation de la viscosité (formation d'un gel), ces additifs pourraient peut-être constituer des agents de mûrissement plus efficaces que l'oxyde de magnésium couramment utilisé à cet effet. Une étude des matrices [UPR + BCP, UPR + PVAc et UPR + P(MMA-co-S)] est réalisée dans un premier temps, les composites BMC et SMC chargés par du carbonate de calcium et renforcés par des fibres de verre étant étudiés par la suite. En absence de charges et de fibres de verre (matrice seule), la nanostructuration est moins efficace que la macroséparation de phase des additifs conventionnels PVAc et P(MMA-co-S) pour compenser le retrait du réseau polyester. Dans un composite en revanche, la nanostructuration conduit à une compensation du retrait intermédiaire entre celles du P(MMA-co-S) et du PVAc. Au niveau de la matrice seule, la nanostructuration permet d'éviter une diminution conséquente de l'énergie de rupture du réseau polyester et permet même dans certains cas une amélioration significative de cette dernière, alors que les additifs conventionnels engendrent un effondrement de cette propriété. Cette différence est cependant beaucoup moins visible dans le cas des composites, les charges entrainant une fissuration prématurée de la matrice. Un composite nanostructuré peut tout de même présenter un renforcement significatif par rapport aux composites conventionnels lorsqu'il contient des nanovides compensateurs de retrait de tailles conséquentes qui améliorent la ténacité du matériau. En ce qui concerne le mûrissement d'un compound SMC par nanostructuration au cours du refroidissement (passage de la transition ordre-désordre), si l'augmentation de la viscosité d'un système réactif UPR + BCP semble suffisamment importante et abrupte, elle est cependant insuffisante en présence des charges ou alors intervient à une température trop faible en raison de l'influence de ces dernières sur la nanostructuration.
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Duaux, Gabriel. "Polymères biosourcés issus de LTTM {glucide polyacide carboxylique eau} : Élaboration et applications dans les matériaux carbonés réfractaires." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI119.
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Les matériaux composites carbone/carbone réfractaires sont constitués de charges granulaires carbonées mises en forme à l’aide d’un liant carbonisable. Jusqu’à présent, le liant utilisé est généralement le brai de goudron houille, cancérigène et visé par REACH. Afin de le substituer par un produit plus respectueux de l’environnement et de la santé des manutentionnaires, nous proposons une solution innovante dans ces travaux de thèse. Les glucides, et plus particulièrement les sucres, sont des composés carbonisables possédant un rendement en carbone faible. En présence de polyacide carboxylique, ceux-ci peuvent former un mélange à transition de phase basse température se caractérisant par un eutectique ou une température d’écoulement plus faible que celle de ses constituants pris séparément. Ce type de mélange est capable de réagir à des températures de l'ordre de 100 °C, donc inférieures à celles communément requises pour des réactions d'estérification. Ce comportement s'apparente à celui déjà décrit pour les BADES (Brønsted Acidic Deep Eutectic Solvent). Dans ces conditions sont obtenus des copolymères (ester-co-oside) linéaires et branchés qui conduisent à un réseau poly(ester-co-oside) en poursuivant la réaction sous vide. Par le choix des constituants et le contrôle du temps de réaction, il est possible de piloter la viscosité des polymères pour les utiliser comme liant dans des composites carbone/carbone à charges granulaires. Dans ce cas, nous avons montré que l’utilisation de polyacides carboxyliques présente trois avantages : i) en mélange avec des sucres, des LTTMs (Low Transition Temperature Mixtures) liquide à température ambiante sont formés, ce qui facilite leur utilisation dans le procédé, ii) ils servent de réactif et de catalyseur pour la polymérisation des sucres et iii) ils permettent d’augmenter le rendement en carbone des liants. Ces résultats sont très prometteurs pour la fabrication de composites carbone/carbone réfractaire comme électrode pour l’électrolyse de l’alumine<br>Refractory carbon/carbon composite materials consist of carbonaceous granular fillers shaped with a carbonisable binder. Until now, the binder used has generally been coal tar pitch, which is carcinogenic and covered by REACH. In order to replace it with a product that is more respectful of the environment and of the health of handlers, we are proposing an innovative solution in this thesis work. Carbohydrates, and more particularly sugars, are carbonisable compounds with a low carbon yield. In the presence of polycarboxylic acid, they can form a low transition temperature mixtures characterised by a eutectic or a lower flow temperature than that of its constituents taken separately. This type of mixture is capable of reacting at temperatures of the order of 100°C, thus lower than those commonly required for esterification reactions. This behaviour is similar to that already described for BADES (Brønsted Acidic Deep Eutectic Solvent). Under these conditions, linear and branched (ester-co-oside) copolymers are obtained which lead to a poly(ester-co-oside) network by continuing the reaction under vacuum. By choosing the constituents and controlling the reaction time, it is possible to control the viscosity of the polymers for use as a binder in carbon/carbon composites with granular fillers. In this case, we have shown that the use of polycarboxylic acids has three advantages: i) when mixed with sugars, LTTMs (Low Transition Temperature Mixtures) that are liquid at room temperature are formed, which facilitates their use in the process, ii) they act as a reagent and catalyst for the polymerisation of sugars and iii) they make it possible to increase the carbon yield of the binders. These results are very promising for the manufacture of refractory carbon/carbon composites as an electrode for alumina electrolysis
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Rouch, Matthias. "Contribution à la compréhension des mécanismes de vieillissement hydrothermique de matériaux composites unidirectionnels polyester insaturé/fibre de lin." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC210/document.
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De nombreux exemples de matériaux composites obtenus par l’association de fibres végétales et de polymères ont permis des allègements conséquents de structures dans divers domaines d’application. Cependant, la question demeure quant de la durabilité de ces pièces en service, essentiellement par manque de connaissances sur le vieillissement des fibres végétales, sur leurs interactions avec la matrice polymère et sur le comportement hydrothermique des composites biosourcés au cours du temps. Dans cette étude, nous avons étudié les cinétiques et mécanismes de sorption du matériau composite afin d’appréhender son comportement hydrique lors des vieillissements hydrothermiques par immersion dans l’eau à 23°C et 70°C. Cette étude a mis en évidence l’influence des fibres végétales sur les grandeurs caractéristiques de l’absorption en eau du matériau composite : forte prise en eau, gonflement anisotrope. Elle a également permis l’identification des mécanismes de dégradation des fibres de lin ; le rôle très nocif des résidus d’écorce rappelle l’importance du rouissage et du défibrage sur les performances de ces fibres. L’étude du comportement des constituants et du composite confrontés à des vieillissements hydrothermiques a ensuite été entreprise afin d’identifier et quantifier l’influence de chacun des matériaux constitutifs, ainsi que leur synergie. Il en ressort que la détérioration des fibres de lin est la principale cause de l’abattement des propriétés mécaniques du matériau composite. Si une immersion à 23°C pendant 70 jours n’a que peu d’effet sur les propriétés mécaniques, l’élévation de la température à 70°C induit des endommagements importants dès 14 jours d’immersion. La destruction des parois cellulaires et la dégradation des interfaces fibre/matrice sous l’effet de la présence d’eau détériorent le transfert de charge matrice/fibre. La corrélation entre les vieillissements accélérés et naturel a fait ressortir une similitude entre le maintien pendant 70 jours dans l’eau à 23°C et l’exposition aux conditions naturelles pendant 24 mois ; l’immersion à 70°C s’avère trop sévère. Une solution d’amélioration serait d’accentuer le rouissage des fibres afin de supprimer davantage les composés pectiques de la lamelle mitoyenne et de la paroi primaire. L’élimination de ces composés facilement hydrolysables par l’eau permettrait de prétendre à une meilleure qualité de l’interface fibres/matrice tout au long du vieillissement<br>A great number of plant fiber – reinforced polymer composites allowed substantial lightening of structures in various fields of application. However, the question remains about the durability of these parts in service, mainly for lack of knowledge about the aging of plant fibers, their interactions with the polymer matrix and the hydrothermal behavior of biosourced composites over time. In this work, water absorption mechanisms and kinetics by the composite material are studied in order to understand the hydric behavior during hydrothermal aging by immersion in deionized water at 23°C or 70°C. The results show that water absorption by the composite is characterized by a high water uptake and an anisotropic swelling. It also allowed the identification of the degradation mechanisms of flax fibers; the very harmful role of bark residues recalls the importance of retting and decortication on the performance of these fibers.The investigation of the behaviors of the constituents and the composite under hydrothermal aging was then undertaken with the aim to identify and quantify the influence of each on the constituent materials, as well as their synergy. It shows that the deterioration of the flax fibers is the main cause of the reduction of the mechanical properties of the composite. If immersion at 23 ° C for 70 days has little effect on the mechanical properties, raising the temperature to 70 ° C induces significant damage from 14 days of immersion. The destruction of the cell walls and the degradation of the fiber/matrix interfaces due to water deteriorate the load transfer efficiency by the fiber/matrix interface. The correlation between accelerated and natural aging showed a similarity between holding for 70 days in water at 23 ° C and exposure to natural conditions for 24 months; immersion at 70 ° C is too severe. An improvement solution would be to increase the retting of the fibers in order to further remove the pectic compounds from the middle lamella and the primary wall. The elimination of these compounds easily hydrolysable by water would claim to a better quality of the fiber / matrix interface throughout aging
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Bessadok, Atef. "Etude et caractérisation des fibres d’Alfa et d’Agave modifiées chimiquement en vue de les incorporer dans un composite à matrice polyester." Rouen, 2007. http://www.theses.fr/2007ROUES028.
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L’objectif principal de ce travail était de modifier et de caractériser des fibres d’alfa et d’agave avant de les incorporer dans une matrice polyester pour préparer des composites ne contenant pas de fibres synthétiques comme la fibre de verre. Les deux types de fibres après traitement chimique présentent des bonnes propriétés mécaniques. Les fibres d’alfa ont une rigidité augmentée, tandis que les fibres d’agave ont une élasticité accrue. Ces fibres cellulosique étant hydrophiles, l’effet de l’eau sur les fibres seules (cinétiques et isothermes de sorption) et sur les composites sous forme de films (régime transitoire et stationnaires de perméation) a été étudié. Plusieurs techniques – énergies de surfaces, spectroscopie infrarouge, microscopie optique à fluorescence et électronique à balayage – ont mis en évidence un accroissement de l’hydrophobie de la surface des fibres traitées, favorable à une meilleure adhésion avec la matrice. Cette amélioration a été confirmée par la diminution de la perméabilité à l’eau des composites élaborés à partir des fibres traitées<br>The main objectives of this work were the chemical modification and the characterization of alfa and agave fibers before their incorporation in an unsaturated polyester matrix in view of preparing composites devoid of synthetic fibers such as fiberglass. Both treated fibers showed improved resistance. The alfa fibers had a higher stiffness, whereas the agave fibers had an increased elasticity. Because these cellulosic fibers are hydrophilic, the effects of water on the fibers alone (sorption kinetics and isotherms) and on the composites prepared as films (permeation in the transitory or steady states) were especially investigated. Several techniques – surface energies, IR spectroscopy, fluorescence microscopy, scanning electronic microscopy – clearly show the increased hydrophobicity of the surfaces of the treated fibers, that is favourable to an improved adhesion with the matrix. This improvement was confirmed by the lower water permeability of the composites containing treated fibers
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Gokce, Neslihan. "Effect Of Fiber And Resin Type On The Axial And Circumferencial Tensile Strength Of Fiber Reinforced Polyester Pipe." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609930/index.pdf.
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In this study, the aim is to investigate the stiffness, longitudinal tensile strength and circumferential tensile strength of short fiber reinforced polyester composite pipes produced by centrifugal casting production method. To achieve this aim, theoretical calculation of modulus of elasticity of pipes was done and then test program was carried out on pipe samples produced with three different resin types which were orthophthalic, isophthalic and vinyl ester resin and three different fiber types which were E glass fiber, ECR glass fiber and basalt fiber. The tests were performed according to ISO (International Organization for Standardization) standards.
When resin type and fiber type effect on the fiber reinforced polyester pipe samples were evaluated, calculated elastic modulus values were in accordance with the test results.
According to the experimental test data, which were used to evaluate the effect of resin type on fiber reinforced polyester pipe properties, there is not a significant difference was observed in the stiffness, longitudinal and circumferential tensile strength test results of pipes having different resin types. In other words, there was not a significant effect of resin type on the stiffness, longitudinal tensile strength and circumferential tensile strength of short fiber reinforced pipes produced by centrifugal casting method.
According to the experimental test data, which were used to evaluate the effect of fiber type on the properties of fiber reinforced polyester pipe, basalt fiber reinforced pipe samples showed higher mechanical performance over E glass fiber and ECR glass fiber reinforced pipes. However, the test results of basalt reinforced polyester pipe were not as good as the individual properties of basalt fiber.
Finally, by comparing the basalt fiber reinforced pipe samples having almost the same stiffness and tensile test results as E glass fiber reinforced pipe samples, the gain in fiber and resin amount were investigated. Basalt fiber reinforced pipes were slightly lighter and thinner than E glass fiber reinforced pipes. However, the decrease in the amount of the fiber and resin in basalt reinforced pipe did not result in an overall cost reduction.
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Rašner, Martin. "Technologická analýza využitelnosti nových typů termosetických materiálů pro konstrukci světlometů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401531.
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The diploma thesis presents the usability of a new thermosetting material BMC for the construction of a car headlight. In the theoretical part there are described headlights, basic characteristics and properties of plastics focussing on polymer composite materials and material testing. The practical part deals with the processing of test samples for mechanical testing by compression moulding and also with the production of real samples of reflectors and carrier frames by injection moulding. The evaluation is based on comparison of the results of the performed tests of alternative material and the currently used BMC TETRADUR TD 492/2 in HELLA Autotechnik Nova s.r.o. Basic physical-mechanical properties such as strength, stiffness, toughness and hardness are tested and monitored. The reflectors and carrier frames are assembled into the headlight and then tested according to legal and customers´ requirements for climate and vibration resistance and photometry.
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Silva, Anderson Ezequiel. "Compósitos de poliéster reforçados com fibra de vidro : efeito da adição de pó de coco nas propriedades mecânicas, morfologia e custos." Universidade Federal de Sergipe, 2013. https://ri.ufs.br/handle/riufs/3505.
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The excessive quantity of byproduct coconut powder as result of processing of coconut fiber, aimlessly industrial application. The objective of this dissertation was the development of composites reinforced with fiberglass using two types of matrices: a pure matrix composite and matrix polyester modified with coir dust. Reducing the size of the coir dust was performed by processing in a ball mill resulting in upper production of particles that crossed off 200 mesh. The composites reinforced with fiberglass and polyester matrix were produced include 10% coir dust (percentage by weight). The viscosity of the pure polyester matrix increased from 244 cP to 480 cP with the addition of coir dust. The step up in viscosity not impair processing of composites, for the reinforcement (fiberglass) was incorporated satisfactorily the two matrices: pure polyester and polyester with coir dust. The mechanical properties were examined through tensile test, three point flexion and IZOD impact. The results of tensile testing of composites reinforced with glass fiber produced with pure polyester matrix and the polyester matrix with coir dust had similar properties. The addition of coconut fiber to matrix produced no change in its performance. Flexion tests showed a 40% reduction in resistance of the polyester matrix composites with coir dust relative to pure polyester matrix composites. The IZOD impact test showed similar results in composites with both types of arrays. There was a 10% reduction in production costs of polyester matrix composites with coir dust, inputs purchased on the overseas market<br>O pó de coco que é um subproduto da indústria de beneficiamento das fibras de coco é produzido em grande quantidade e não possui aplicações industriais. O objetivo desta pesquisa foi o desenvolvimento de compósitos reforçado com fibra de vidro empregando dois tipos de matrizes: poliéster puro e poliéster com pó de coco. A redução do tamanho do pó de coco foi realizado através de processamento em moinho de bolas obtendo-se alta produção de partículas que passaram na malha de 200 mesh. Os compósitos reforçados com fibra de vidro foram produzidos com matriz poliéster contendo 10 % de pó de coco (porcentagem em peso). A viscosidade da matriz poliéster pura aumentou de 244 cP para 480 cP com a adição de pó de coco. O aumento da viscosidade não prejudicou o processamento dos compósitos, pois o reforço (fibra de vidro) foi incorporado satisfatoriamente às duas matrizes: poliéster puro e poliéster com pó de coco. As propriedades mecânicas foram analisadas através de ensaios mecânicos de tração, flexão em três pontos e impacto IZOD. Os resultados dos ensaios de tração dos compósitos reforçados com fibra de vidro produzidos com matriz poliéster pura e matriz de poliéster com pó de coco apresentaram propriedades semelhantes. A adição do pó de coco à matriz não produziu mudanças no seu desempenho. Os ensaios de flexão apresentaram redução de 40% na resistência dos compósitos de matriz poliéster com pó de coco em relação aos compósitos de matriz poliéster pura. O ensaio de impacto IZOD apresentou resultados similares nos compósitos com os dois tipos de matrizes. Houve uma redução de 10% nos custos de produção dos compósitos de matriz poliéster com pó de coco, com insumos adquiridos no mercado internacional
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Rabe, Richard L. "Corona discharge effects on the interfacial adhesion in a sheath-core type composite fiber." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1172603429.
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Oliveux, Géraldine. "Influence des conditions d'hydrolyse sous-critique sur le recyclage des matériaux composites fibres de verre / résine polyester insaturé : influence des conditions et de la structure de la résine sur les cinétiques réactionnelles." Nantes, 2012. http://www.theses.fr/2012NANT2110.
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Un procédé d’hydrolyse en conditions batch est étudié pour rompre les liaisons ester de résines polyester insaturé et réticulé au styrène, matrices de matériaux composites renforcés de fibres de verre. Des conditions sous-critiques biphasiques apparaissent adaptées compte tenu de la chimie en jeu. La réaction d’hydrolyse suit en effet un mécanisme Aac2 et nécessite donc des conditions favorables à la réalisation de réactions ioniques, à savoir en particulier un produit ionique et une constante diélectrique relative de l’eau suffisants. Elle permet de récupérer en particulier les monomères d’origine de la résine. Mais ceux-ci subissent également des réactions secondaires ioniques. Ce traitement par hydrolyse affecte par ailleurs la qualité des fibres de verre récupérées. Elles sont corrodées, perdant ainsi une partie de leurs propriétés mécaniques, et nécessitent une phase de rinçage pour les débarrasser des substances organiques résiduelles. Des conditions ont cependant pu être identifiées comme permettant de minimiser la dégradation de leurs propriétés mécaniques. Ces conditions permettent également un taux de récupération maximal en monomères de la résine. Ainsi en moins d’une heure à 275°C, il est possible de rompre quasiment toutes les liaisons ester de la résine. Prolonger la durée de traitement ne fait que permettre aux réactions secondaires de se poursuivre. Un fonctionnement semi-continu s’avère indispensable pour minimiser les réactions secondaires et éviter l’étape ultérieure de rinçage des fibres. Il peut permettre par ailleurs une dégradation moins importante de ces dernières<br>A hydrolysis process in batch conditions is applied to break ester bonds of unsaturated polyester resins, crosslinked with styrene, as matrices of composite materials reinforced with glass fibres. Subcritical two-phase conditions appear adapted in view of the involved chemistry. The hydrolysis reaction follows in fact an Aac2 mechanism and requires then conditions enhancing ionic reactions, that is to say in particular sufficient values of the ionic product and of the relative dielectric constant of water. It allows the recovery of the initial monomers of the resin. But the latter’s are subjected to secondary ionic reactions. This hydrolysis treatment also affects the quality of the recovered glass fibres. They are corroded, loosing thus some of their mechanical properties, and require a washing phase to remove residual organic components. Conditions have however been identified as allowing minimizing the degradation of their mechanical properties. Those conditions also allow a maximum recovery rate of the initial monomers of the resin. Thus in less than an hour, it is possible to break almost all the ester bonds of the resin. A longer treatment time only allows secondary reactions to continue. A semi-continuous process appears to be essential to minimize secondary reactions and avoid the washing post-treatment of the fibres. It can also allow a less important degradation of them
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Oliveira, Jos? Orlando de. "Comp?sito refor?ado com sisal para aplica??o na moda." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15680.
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Previous issue date: 2012-03-30<br>The objective of this research is the fabrication of a composite reinforced with dyed sisal fiber and polyester matrix for application in the fields such as, fashion, clothing,
interior textiles; fashion accessories are some of the examples. For the fabrication of the composite, the sisal fibers were subjected to processes such as: chemical treatment with sodium hydroxide (NaOH) in the removal of impurities; bleaching for
removing the yellowish color of the natural fiber and dyeing with direct dyes to confer the colors blue, green and orange. The search for new technologies ecologically correct has become a major concern in recent decades. Studies show that composite
polymer reinforced by natural fibers is suitable for a large number of applications, and its use is advantageous in terms of economic and ecological. The dyed fibers were cut to a length of 30 mm, is used in the confection of webs. For this purpose, a web
preparer by immersion, developed in the Laboratory of Chemical Textile of UFRN. The composite sheets measuring 300 x 300 x3 mm were molded by compression, with unsaturated orthophthalic polyester as matrix, and the samples in sizes 150 x 25
x 3 mm were cut with the aid of a laser machine, to be subjected to traction and flexion. The mechanical properties of traction and flexion in three points were performed in the Laboratory of metal and mechanical tests of Materials Engineering
of UFRN. The resulting samples from the tests were evaluated in scanning electron microscope (SEM) at CTGas RN. On the basis of the analysis of the results from the mechanical tests, it was observed that the composite had good mechanical behavior,
both in traction as in flexion. Furthermore, it was observed that in the water absorption test, the samples had a different percentage among themselves, this occurred due to the variation of density found in the fibre webs. The images of the
SEM showed the failures from the manufacturing process and the adhesion of fibre/matrix. When the samples were prepared with the dyed fibers to be applied in fashion, the results were positive, and it can be concluded that the main objective of
this work was achieved<br>A busca por novas tecnologias ecologicamente corretas tem se tornado uma grande preocupa??o nas ?ltimas d?cadas. Estudos comprovam que comp?sitos polim?ricos refor?ados por fibras naturais s?o adequadas a um grande n?mero de aplica??es e
seu uso ? vantajoso em termos econ?micos e ecol?gicos. O objetivo desta pesquisa ? a fabrica??o de um comp?sito refor?ado com fibra de sisal tingida e matriz de
poli?ster para aplica??o na moda: vestu?rio, t?xteis lar, acess?rios de moda etc. Para o seu beneficiamento, as fibras de sisal foram submetidas aos diversos processos: tratamento qu?mico com hidr?xido de s?dio (NaOH) na retirada das
impurezas; alvejamento para remo??o da cor amarelada natural da fibra e tingimento com corantes diretos para conferir as cores azul, verde e alaranjado. As fibras tingidas foram cortadas com comprimento de 30 mm e utilizadas na confec??o das
mantas. Para isso utilizou-se um preparador de manta por imers?o, desenvolvido no Laborat?rio de Qu?mico T?xtil da UFRN. Os comp?sitos medindo 300 x 300 x 3 mm foram moldados por compress?o, com poli?ster insaturado ortoft?lico como matriz, e
as amostras nos tamanhos 150 x25 x3 mm foram cortadas com aux?lio de uma m?quina ? laser, para serem submetidas ? an?lise mec?nica de tra??o e flex?o. As propriedades mec?nicas de tra??o e flex?o em tr?s pontos foram realizadas no
Laborat?rio de Metais e Ensaios Mec?nicos de Engenharia de Materiais da UFRN. As amostras resultantes das propriedades mec?nicas foram avaliadas no Microscopio Eletronico de Varredura (MEV) no CTG?s RN. Com base nas an?lises
dos resultados dos ensaios mec?nicos, observou-se que os compositos tiveram bom comportamento mec?nico, tanto na tra??o como na flex?o. Tamb?m observou-se que no ensaio de absor??o de ?gua, as amostras tiveram um percentual diferente
entre si, isso ocorreu devido ? varia??o da densidade encontrada nas mantas. As imagens do MEV mostraram as falhas provenientes do processo de fabrica??o e a ades?o fibra/matriz. Quando foram preparadas as amostras com as fibras tingidas
para serem aplicadas na moda, os resultados foram positivos e pode-se concluir que o objetivo principal do presente trabalho foi atingido
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White, Roger John. "Environmental creep mechanisms in glass/polyester composites." Thesis, University of Bath, 1985. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353403.
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A previous study, looking at the creep-rupture behaviour of mixed reinforcement GRP when immersed in water, had discovered that low loads, behaviour became temperature sensitive. Since the recorded time to failure of a sample was reduced at elevated temperatures, from that predicted by a linear extrapolation of the short term creep-rupture results, this deviation caused problems in the accurate prediction of long-term design stresses. In order to improve the accuracy of long term design predictions, it was decided to study the mechanisms of creep in GRP that initiates time dependent failure. From this, it was hoped that accurate design criteria suitable for predicting GRP response over a 30 year design life from short term creep tests, could be developed. This thesis reports the results obtained from such a study. A series of creep tests were performed on mixed reinforcement GRP samples at several stress levels, both in air, and in room temperature distilled water, using a microcomputer based data collection system. In conjunction with this work, damage development in samples, due to combinations of water uptake and creep loading, was followed, using both scanning electron, and optical, microscopy. Moisture uptake measurements were undertaken under a series of load/temperature regimes, and fibre/matrix debonding followed using photographic techniques. In this way, water absorption, both in terms of uptake rate, and location within a sample, could be characterised. Tensile tests were also performed to determine the standard mechanical properties of the mixed reinforcement GRP used. It was found that a critical damage state was created at loads in excess of 50% of ultimate, but not below. This took the form of between 2 and 8 neighbouring filament breaks in the longitudinal woven rovings at weave crossover points, producing microcracks in the reinforcement. The creation of this multifilament fracture damage during primary creep, was considered to be necessary for time dependent failure to occur in air. Secondary greep strain was found to increase in discrete steps, both in air and water. This was attributed to the formation of transverse grasks in the longitudinal woven rovings, propogating from the above critical damage. In water, diffusion was found to be non-Fickian. Moisture uptake increased with increases in applied load and temperature. Water was seen to accumulate at weave cross-over points when immersed under load. This led to stress-enhanced fibre corrosion in these regions, weakening the reinforcement, and reducing the failure time from that expected at the same load level in air. The localised nature of moisture degradation was thought to result in the formation of critical fibre damage at loads below 50% of ultimate, when immersed in water. Two design criteria based on the observed creep mechanisms, have been developed for GRP that predict response when loaded in either air, or water. Both predict the existence of creep-rupture limits at low loads.
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Aoujdad, Khalid. "Caractérisatiοns ultrasοnοres du vieillissement de pales d’hydroliennes et d’éoliennes en milieu marin. : Cοnfrοntatiοn aux essais mécaniques". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMLH24.
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Cette thèse porte sur la caractérisation non destructive par ondes ultrasonores des échantillons représentatifs des pales d’éoliennes offshore, avec confrontation aux tests mécaniques. Les échantillons sont en matériaux composites à base de la résine polyester renforcée par des fibres de verre UD GFRP (Unidirectional Glass Fibers Reinforced Polyester). Ils sont soumis à un vieillissement accéléré dans l’eau de mer chauffée à 40 °C et à 60 °C, afin de simuler le milieu marin et réduire la durée d’étude. L’objectif est de trouver des paramètres acoustiques sensibles au vieillissement permettant d’évaluer l’effet du vieillissement ou de le quantifier. L’analyse par ondes guidées de Lamb a montré une diminution des vitesses de phase des modes et de la vitesse de Rayleigh, ainsi que l’augmentation de l’atténuation dans le matériau, ce qui indique que les propriétés mécaniques des matériaux se dégradent à cause du vieillissement. L’imagerie C-scan montre une dégradation de la résine, entraînant la réorganisation des fibres et la modification de leur alignement. Une modélisation numérique par la méthode des éléments finis de la propagation des ondes guidées dans ces matériaux a montré que les propriétés structurelles et géométriques des matériaux se dégradent à cause du vieillissement. Les paramètres les plus attaquées sont les constantes d’élasticité, ainsi que la masse volumique pour des vieillissement plus forts et plus longs. Enfin, le nombre des plis des renforts dans un échantillons joue un rôle important dans sa résistance au vieillissement<br>This thesis discusses the ultrasonic non-destructive characterization of representative samples of offshore wind turbine blades. The samples are made of composite materials based on Unidirectional Glass Fibers Reinforced Polyester (UD GFRP). Samples are subjected to accelerated aging in heated seawater at 40°C and 60°C, in order to simulate the marine environment and reduce study times. The aim is to find acoustic parameters sensitive to aging, enabling the effect of aging to be assessed or quantified. Lamb's guided wave analysis showed a decrease in mode phase velocities and Rayleigh velocity, as well as an increase in attenuation in the material, indicating that the mechanical properties of the material are degrading due to aging. C-scan imaging shows degradation of the resin, leading to reorganization of the fibers and changes in their alignment. Finite element numerical modelling of guided wave propagation in these materials has shown that the structural and geometric properties of the materials degrade with age. The parameters most affected are the elasticity constants, as well as the density for stronger and longer aging. Finally, the number of reinforcement plies in a sample plays an important role in its resistance to aging
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Novák, Petr. "Vlastnosti lakových kompozitních materiálů plněných mikro- a nanočásticemi." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219042.
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The presented work deals with preparation of test samples filled microparticles of mica and nanoparticles of silicon dioxide (SiO2). Monitors the impact of climatic conditions and filler on electrical properties of composite materials. Electrical properties of composite materials are measured by dielectric relaxation spectroscopy. Test samples influence of epoxide resin TSA 220S and polyester resin DOLPHON XL 2102. Varnishes are modified with different weight percentage of nanoparticles of silicon dioxide, or micronized mica. The results of this project are frequency dependencies of parts of complex permittivity and their evaluation.
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Han, Xiaoxiao. "Degradation models for polyesters and their composites." Thesis, University of Leicester, 2011. http://hdl.handle.net/2381/10275.
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Intensive studies are being carried out to use devices made of bioresorbable polymers inside the human body to provide various temporary functions. Typical examples include scaffolds for tissue engineering, fixation screws for broken bones and drug-loaded matrices for controlled-release. The development is entirely based on trial and error. The degradation rate strongly depends on the shape and size of the devices, making it difficult to transfer experience from one device to another. The degradation time ranges from weeks to years; animal and ultimately human trials have to be carried out, making the trial and error approach time-consuming and expensive. The entire field would benefit enormously from mathematical models capable of predicting the degradation and property change of the devices. This PhD project will develop such models as following: a) A multi-scale model for degradation of bioresorbable polyesters was developed. Events that occur at the molecular scale are modelled at the molecular scale using the kinetic Monte Carlo schemes while events that occur at the device scale are modelled using macroscopic diffusion model. b) A phenomenological model for simultaneous crystallisation and biodegradation of biodegradable polymers was developed. This model completed the degradation theory developed by Wang et al. at University of Leicester. c) The model in (b) was improved and applied to the analysis of accelerated degradation data. Temperature effects were taking into account by using Arrhenius relations. d) A model for the biodegradation of composite materials made of polyesters and calcium phosphates was developed. A calcium phosphate effectiveness map is established to show the conditions under which incorporating calcium phosphates into polyesters is effective, saturated or ineffective. f) A phase field model was developed for drug release from a swelling Hydroxypropyl methylcellulose matrix. This model can be readily extended to full three dimensional problems.
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Lima, Jos? Henrique Batista. "Desenvolvimento de t?xteis t?cnicos para refor?o de comp?sitos polim?ricos." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15684.
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Previous issue date: 2012-05-02<br>Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico<br>Materials denominated technical textiles can be defined as structures designed and developed with function to fulfill specific functional requirements of various industrial sectors as are the cases of the automotive and aerospace industries. In this aspect the technical textiles are distinguished from conventional textile materials, in which the aesthetic and of comfort needs are of primordial importance. Based on these considerations, the subject of this dissertation was established having as its main focus the study of development of textile structures from aramid and glass fibers and acting in order to develop the manufacture of composite materials that combine properties of two different structures, manufactured in an identical operation, where each structure contributes to improving the properties of the resulting composite material. Therefore were created in laboratory scale, textile structures with low weight and different composition: aramid (100%), glass (100%) and aramid /glass (65/35%), in order to use them as a reinforcing element in composite materials with polyester matrix. These composites were tested in tension and its fracture surface, evaluated by MEV. Based on the analysis of mechanical properties of the developed composites, the efficiency of the structures prepared as reinforcing element were testified by reason of that the resistance values of the composites are far superior to the polyester matrix. It was also observed that hybridization in tissue structure was efficient, since the best results obtained were for hybrid composites, where strength to the rupture was similar to the steel 1020, reaching values on the order of 340 MPa<br>Os materiais denominados t?xteis t?cnicos podem ser definidos como estruturas projetadas e desenvolvidas com a fun??o de atender a requisitos funcionais espec?ficos de diversos setores da ind?stria, caso da ind?stria automotiva e aeroespacial. Nesse aspecto, distinguem-se dos materiais t?xteis convencionais, nos quais as necessidades est?ticas e de conforto t?m import?ncia primordial. Com base nessas considera??es, o tema dessa disserta??o foi estabelecido tendo como enfoque principal o estudo do desenvolvimento de estruturas t?xteis a partir de fibras de aramida e de vidro, atuando no sentido de elaborar a fabrica??o de materiais comp?sitos que combinem propriedades de duas estruturas diferentes, fabricadas em uma mesma opera??o, onde cada estrutura contribui para melhoria das propriedades do material comp?sito resultante. Para tanto foram desenvolvidas em escala laboratorial estruturas t?xteis de baixa gramatura e composi??o diferenciada de aramida (100%), vidro (100%) e aramida/vidro (65/35%) para utiliza??o como elemento refor?ante em comp?sitos com matriz de poli?ster. Os comp?sitos produzidos foram ensaiados em tra??o e sua superf?cie de fratura avaliada por MEV. Com base nas analises das propriedades mec?nicas dos comp?sitos desenvolvidos, observou-se a efici?ncia das estruturas ou elaboradas como elemento refor?ante tendo em vista que os valores de resist?ncia dos comp?sitos foram muito superiores ? matriz de poli?ster. Tamb?m foi observado que a hibridiza??o na estrutura dos tecidos foi eficiente, uma vez que os melhores resultados obtidos foram para os comp?sitos h?bridos, onde a resist?ncia na ruptura foi semelhante ? do a?o 1020, atingindo valores na ordem de 340 MPa
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Vangrimde, Bart. "Comportement mécanique des joints boulonnés en composites verre-polyester." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ65533.pdf.
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Nguyen-Hoa, Hoi. "Prévision de la rupture des composites polyester/tissus de verre." Sherbrooke : Université de Sherbrooke, 1999.
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Hughes, John Mark. "On the mechanical properties of bast fibre reinforced thermosetting polymer matrix composites." Thesis, Bangor University, 2000. https://research.bangor.ac.uk/portal/en/theses/on-the-mechanical-properties-of-bast-fibre-reinforced-thermosetting-polymer-matrix-composites(0fdca4e4-8d50-4a16-afd0-37d78cfb8a64).html.
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Bast fibre reinforced, unsaturated polyester matrix composites were fabricated using non-woven mats of hemp or jute fibre as reinforcement. Composites were also prepared using chopped strand mat glass fibre as reinforcement. The short-term mechanical properties of the laminates were assessed. It was observed that at equivalent fibre volume fractions the stiffness of the glass fibre reinforced material only marginally exceeded that of the two, unmodified bast fibre, reinforced materials. At equivalent fibre volume fractions, however, the strength of the glass fibre reinforced composite was found to be significantly greater than that of the bast fibre reinforced materials. It was noted that in the bast fibre reinforced composites, the onset of non-linear behaviour occurred at relatively low applied stresses. Work of fracture in static three-point flexure and Charpy impact strength tests, indicated that the toughness of the plant fibre reinforced material was as much as an order of magnitude less than that of the glass fibre reinforced material. Fracture mechanics techniques were used to further quantify toughness and confirmed this to be so. Furthermore, these tests indicated that the microstructure of the bast fibre reinforced material should be examined more closely. Microscopy conducted on the fibres revealed that these were often subject to extensive micro-compressive damage. It was postulated that uneven fibre straining characteristics could lead to compromised interfacial properties, which might in turn detrimentally affect the macroscopic behaviour of the composite. A technique known as half fringe photoelasticity was used to investigate the stress-field in the matrix surrounding the fibre defects. It was observed that not only did concentrations of stress occur in the vicinity of these, but also that the shear stress distribution along the length of the fibre was interrupted by the presence of the defects. The implications of fibre defects upon composite properties are discussed.
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Shohada, Mohsen-Fadaee. "Polyester resin concrete : mix development and the structural behaviour of some components." Thesis, Durham University, 1987. http://etheses.dur.ac.uk/9299/.
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Do, Thanh Viet. "Étude du retrait du polyester renforcé par des tissus de verre." Sherbrooke : Université de Sherbrooke, 2001.
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Saharudin, Mohd. "Mechanical properties of polyester nano-composites exposed to liquid media." Thesis, Northumbria University, 2017. http://nrl.northumbria.ac.uk/36179/.
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Halloysite nanotubes (HNTs) offer excellent improvements in wide range of physical and engineering properties at low filler content. Due to their outstanding properties such as large aspect ratio, high surface area, flame retardant and good optical clarity, HNTs polymer nanocomposites are widely used in automotive, coating, packaging and medical devices. The results showed that the incorporation of halloysite nanotubes (HNTs) into polyester significantly improved dynamic mechanical properties of the nanocomposites including the glass transition temperature (Tg), storage moduli, microhardness, tensile properties, flexural properties and impact toughness. The mechanical properties of polyester-based nanocomposites were degraded after water-methanol exposure. The maximum microhardness, tensile, flexural and impact toughness values were measured at 1 wt% of HNTs reinforcement and the results also showed that HNTs improved the liquid barrier properties of polymers due to an increase in the tortuosity path. Several deterioration effects are likely to take place concurrently after seawater exposure. Plasticization reduced the mechanical properties of the nanocomposites and microorganisms such as microbes entered through microvoids to further increase the deterioration in mechanical properties of the nanocomposites. Microbes can cause chemical degradation and the breakage of hydrocarbons using seawater molecules. Nanocomposite biodegradation is highly undesirable for material integrity as these are mostly used in structural designs of marine applications. Structural damage may result in premature weakening which is often translated into system failure and enormous economic losses. The influence of short-term water absorption on the mechanical properties of HNTs-multi layer graphene-reinforced polyester hybrid nanocomposites was also investigated. After short-term water exposure, the maximum microhardness, tensile, flexural and impact toughness values were observed in case of polyester-multi-layer graphene (MLG) nanocomposites. It was also found that synergistic effects were not effective at a concentration of 0.1 wt % in producing considerable improvement in the mechanical properties of the hybrid nanocomposites.
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Nguyen-Hoa, Hoi. "Prévision de la rupture des composites polyester/tissus de verre." Mémoire, Université de Sherbrooke, 1999. http://savoirs.usherbrooke.ca/handle/11143/1139.
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Polyester/glass fiber is probably by far the most commonly used composite. This work presents the results of an investigation on the failure of plain weave and 8-harness satin glass/polyester composites. To predict the failure strengths of any deformed fabric composites, the sub-plies model was used. In this model, woven fabric composites are divided into four fictional unidirectional sub-plies with orthotropic properties that are laid up in an unsymmetrical configuration. Consequently, the strength of woven fabric laminate is predicted as a function of the failure parameters of the constituent sub-plies and the in-plane shearing deformation angle between these plies. Another major advantage of the model is that it allows the direct use of laminated shell element in finite element codes for structural analysis. In order to take account of fiber undulation effect on mechanical properties, a procedure for the determination of the equivalent on-axis tensile and compressive strength coefficients of the constituent plies is also proposed."--Résumé abrégé par UMI
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Delfolie, Corinne. "Phénomènes d'interface et réponse mécanique dans des composites polyester - verre." Lille 1, 1996. http://www.theses.fr/1996LIL10221.
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L'objectif de ce travail a consisté à évaluer l'influence des caractéristiques de l'interface sur la réponse mécanique de composites à renfort fibre de verre et à matrice polyester insaturé. L'ajout de certains thermoplastiques, dits additifs low profile (lpa) dans le mélange prépolymère(up)-styrène(st) permet d'éliminer le retrait volumique qui accompagne la formation du réseau polyester. Les additifs lpa incorporés dans la matrice sont soit le polyacétate de vinyle (pvac), soit un terpolymère méthacrylate de méthyle / acide méthacrylique / méthacrylate hydroxyle (pmma(oh)). Les ensimages sont compatibles avec chaque formulation, et se différencient vis-à-vis de leur solubilité, qui traduit en fait le degré d'accrochage de l'agent filmogène sur la fibre. La confrontation de données micro et macromécaniques, et physico-chimiques permet d'établir un schéma de constitution de l'interface dans les différents systèmes<br>Les influences respectives du degré de solubilité et de la nature de l'additif sur la microstructure de l'interphase sont découplées. Dans les systèmes insolubles, l'ensimage formant un réseau réticule à la surface du verre, son influence sur la thermodynamique locale est réduite. La liaison à l'interface est assurée par la formation d'un réseau interpénètre réticule, ce qui confère un caractère fragile à l'interface dans ces composites. Dans le cas soluble, la nature de l'additif low profile est déterminante dans la constitution de l'interphase. Pour le système à base pvac, la solubilisation partielle de l'ensimage modifie localement le diagramme de phase ternaire up-st-lpa, et conduit à la ségrégation du thermoplastique à l'interface. L'interphase a alors un caractère plutôt ductile. Pour le système à base pmma(ho), le développement de liaisons hydrogène au sein de l'additif limite la solubilisation de l'ensimage, et donc son influence sur la gélification de la résine. Les ponts hydrogène jouant le rôle de nœuds de réticulation, le schéma de constitution de l'interface est similaire à celui du système insoluble
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Castaing, Philippe. "Vieillissement des matériaux composites verre-polyester en milieu marin : délaminage d'origine osmotique." Toulouse, INPT, 1992. http://www.theses.fr/1992INPT016G.
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Les materiaux composites a matrice polyester insature et a fibres de verre sont sujets a un cloquage d'origine osmotique lorsqu'ils sont au contact de l'eau en general et de l'eau de mer en particulier. Ce phenomene s'avere nuisible car il conduit a terme au delaminage des structures. Les resultats d'une etude systematique du cloquage de ces composites en milieu aqueux en vue de son interpretation sont decrits dans le present manuscrit. En plus d'une introduction et d'une conclusion, le memoire comporte trois parties principales: la premiere qui est constituee de rappels bibliographiques fait le point sur le vieillissement et le cloquage des composites polyester/fibres de verre; la seconde detaille les tests de vieillissement acceleres auxquels sont soumis ces materiaux et les methodes physico-chimiques et mecaniques mises en uvre pour le suivi de l'endommagement; la troisieme rassemble les resultats des tests et propose une modelisation mecanique du cloquage elaboree a partir de la theorie des plaques et permettant une prediction du delaminage des structures
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Caddock, Brian David. "The influence of diffusion processes on the stress-corrosion of E-glass/polyester composites." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237537.
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Galv?o, Alcione Olinto. "Desenvolvimento e an?lise de material comp?sito a base de penas de frango (fibras de queratina-KF) e matriz de poli?ster insaturado." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15670.
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Previous issue date: 2011-08-26<br>Use of natural fibres as a reinforcement material in the manufacture of composites show a series of advantages: availability, biodegradability, low weight and regeneration in relation to synthetic fibres, thus justifying its utilization. In the present research work, composites were developed with chicken feathers (KF), using unsaturated polyester resin as matrix, for diversified applications, mainly in the furniture/timber industry.At present, in Brazil the chicken feathers are used as part of the animal feed, even though this material possesses low aggregated value. The chicken feathers are hollow, light and resistant. After washing with water at room temperature, a part of the chicken feathers were treated with 2% NaOH. Composites were manufactured using treated and untreated chicken feathers with unsaturated orthothalic polyester resin and 1% peroxide as catalyser, obtained in the commerce. Samples with size 150x25x3 mm for mechanical tests were cut by laser in the composite plate. Mechanical analyses were carried out in the Laborat?rio de Metais e Ensaios Mec?nicos UFRN. All the analyses were in accordance with ASTM standards. SEM analyses were also carried out on the samples.In the analyses of the results obtained, it was observed that the composites made with untreated chicken feathers showed better results (Traction 11.406 MPa and 9.107 MPa Bending 34.947 and 20.918 MPa for samples with and without treatment respectively) compared to the composite with treated feathers. Very low values of the water absorption results, evidenced the impermeability characteristic of the feathers. From the SEM images, the structure, fracture and the fibre/matrix adsorption can be evidenced. In the flammability test, it was observed that despite the feathers having sulfur as a constituent, natural inhibitor of flame, no burning support of the composites, because the manufacturing process of the composite<br>O uso de fibras naturais como refor?o em comp?sitos apresenta uma s?rie de vantagens: abund?ncia, biodegradabilidade, baixo peso e regenerabilidade em rela??o ?s fibras sint?ticas, justificando sua utiliza??o. Na presente pesquisa foram desenvolvidos comp?sitos com penas de frango (KF), utilizando resina de poli?ster n?o-saturado como matriz. Atualmente, no Brasil, as penas de frango s?o utilizadas como parte de ra??o animal, por?m este produto possui um baixo valor agregado. As penas s?o um material oco, leve e resistente. Ap?s a lavagem com ?gua em temperatura ambiente uma parte das penas foi tratada com 2% de NaOH. Foram fabricados dois comp?sitos, um com as penas tratadas e outro sem tratamento, usando o processo de molde fechado por compress?o, utilizando a resina de poli?ster ortoft?lica e 1% de per?xido MEK (per?xido de metil etil cetona) como iniciador, adquiridos no com?rcio local. As amostras com 150x25x3 mm de tamanho para os ensaios mec?nicos foram cortadas a laser na placa do comp?sito. Os ensaios de tra??o e flex?o em tr?s pontos foram realizados no Laborat?rio de Metais e Ensaios Mec?nicos - UFRN. Todas as an?lises estavam de acordo com as normas da ASTM. As amostras resultantes dos ensaios mec?nicas foram avaliadas no MEV. Com base nas observa??es dos resultados nos ensaios mec?nicos, (Tra??o 11,2 Mpa e 8,3 Mpa; Flex?o 34,9 Mpa e 22,9 MPa para as amostras sem e com tratamento respectivamente) observou-se que os comp?sitos refor?ados com as penas sem tratamento apresentaram um melhor comportamento quando foram expostos a carregamentos tanto de tra??o quanto de flex?o. O ensaio de absor??o evidenciou nos valores de absor??o de ?gua, uma das caracter?sticas da prote?na existente nas penas, a queratina, a sua capaciade de impermiabiliza??o a ?gua. Nas imagens do MEV foi poss?vel verificar a estrutura da pena, as regi?es de ruptura do comp?sito e a ades?o fibra/matriz. No ensaio de inflamabilidade, observou-se que apesar das penas terem como constituinte o enxofre, inibidor natural de chama, n?o houve a susten??o da queima nos comp?sitos, devido o processo de fabrica??o do comp?sito