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Design And Characterization Of Electromagnetic Wave Absorbing Structural CompsitesGurer, Goksu 01 September 2010 (has links) (PDF)
Electromagnetic interference (EMI) is one of the most common problems encountered in microwave applications. Interaction of electromagnetic (EM) waves from different sources may result in device malfunction due to misinterpretation of the transferred data or information loss. On the other hand, development of materials with reduced radar detectability is desired in defense applications. Considering the limitations in weight and thickness, development of lightweight structural materials with enhanced electromagnetic absorption potential is needed. In this study, development and characterization of glass fiber-reinforced polymer (GFRP) composite materials to be used in EM wave absorbing or EMI shielding applications was aimed. Incorporation of electromagnetic wave absorption characteristic has been achieved by the application of conductive thin film on fiber glass woven fabric reinforcement layers. Characterization of EM wave absorption potential was conducted using &ldquo / free-space method&rdquo / in 18 &ndash / 27 GHz frequency range. Single and multilayered combinations of surface-modified fiber glass woven fabrics were characterized in terms of their EM wave interaction properties and design principles for efficient broadband EM wave absorbing multilayered GFRP composite material have been presented. A computer aided computation method has also developed in order to predict EM wave transmission, reflection, and hence absorption characteristics of multilayered structures from single layer properties. Estimated results were verified compared to free-space measurement results. In the current study, up to 85% electromagnetic wave absorption has been obtained within 18-27 GHz frequency range (K band). Enhancement of EM wave absorption potential of multilayer structure has also been demonstrated by computer aided computation.
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Neue Beschichtungsverfahren für PVA-Zement-Composite in textilbewehrtem BetonGlowania, Micheal, Weichold, Oliver, Hojczyk, Markus, Seide, Gunnar, Gries, Thomas 03 June 2009 (has links) (PDF)
Im Rahmen des Transferprojektes T01 „Textilbeschichtung mit hochviskosen Massen“ des Sonderforschungsbereiches 532 (SFB 532) wird die Realisierung und Bewertung eines integrierten Beschichtungskonzeptes zur nachhaltigen Verbesserung der Tragfähigkeit von textilbewehrten Betonbauteilen an der RWTH Aachen University untersucht. Dazu wird eine neue Auftragstechnik für hochviskose Beschichtungsmassen entwickelt, die eine vollständige Penetration von Multifilamentgarnen mit großen Garntitern und einer hohen Anzahl an Filamenten in textilen Gelegen erzielt. Des Weiteren werden aktive Beschichtungsmassen auf der Basis von Polyvinylalkohol-Zement-Compositen, die eine homogene Anbindung aller Einzelfilamente an die Zementmatrix ermöglichen, erforscht.
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Use of non-steel fiber reinforcement in concrete tunnel liningSeo, Sang Yeon 26 January 2011 (has links)
Fiber reinforcement is being widely used in concrete tunnel linings these days. Using fiber reinforcement can save not only cost, but also labor and time spent on construction. However, many owners hesitate to incorporate fiber reinforcement in tunnel lining due to lack of experience with and knowledge of the behavior of fiber reinforced concrete (FRC)
In this study, fiber reinforced concrete was made with various kinds of fibers such as steel fiber, macro-synthetic fiber and hybrid fiber (a blend of macro-synthetic fiber and glass fiber). Many experimental tests were performed to investigate the compressive, flexural and shear behavior of fiber reinforced concrete. In addition to the structural capacity of FRC, the distribution of fiber reinforcement inside the concrete matrix was investigated. Test results of these experimental tests were thoroughly examined to compare and quantify the effects of fiber reinforcement. Next, the test results were used to generate axial force-bending moment interaction diagrams based on current design approaches. In addition, the current design approaches were modified to estimate the accurate and exact value of bending moment. Fiber reinforcement clearly improved the structural performance of tunnel lining. The post-peak flexural and shear strength was significantly influenced by the type and amount of fiber reinforcement. / text
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Long term and short term deflection of GFRP prestressed concrete slabsSingh, Mahendra 25 June 2014 (has links)
This thesis investigates the performance of GFRP pretensioned concrete slabs and compares their flexural behaviour with GFRP reinforced and steel prestressed concrete slabs. A total of 12 slabs were cast in this program. The slab mid-span deflections are theoretically predicted and the results indicate that the short-term response of GFRP prestressed concrete slabs can be predicted well by the existing methods. Long-term deflection behaviour has been estimated using the Age Adjusted Effective Modulus Method by incorporating three creep and shrinkage models. A large influence of creep and shrinkage models on the theoretical determination is observed and the use of long term multipliers is not suitable for GFRP prestressed concrete members. The slabs were instrumented for long-term monitoring using strain gauges and fibre-optic sensors. It was concluded that the electrical strain gauges can be successfully used for long-term strain monitoring.
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Korrelation der makroskopischen Alterung mit nanoskaligen Veränderungen in hybriden Polymer/Zement-Oberflächenaktivierungen für Glasfaserrovings in TextilbetonHojczyk, Markus, Weichold, Oliver, Walther, Andreas, Möller, Martin 03 December 2011 (has links) (PDF)
Hybride Oberflächenaktivierungen von Glasfaserrovings mittels Polymer/Zement-Kompositen ermöglichen eine komplette Durchdringung des Rovings mit Beton von der Matrix bis zu den innenliegenden Einzelfilamenten. Dies erlaubt einen deutlich verbesserten Lasteintrag in den gesamten Rovingquerschnitt bei der Verwendung als Faserverstärkung in textilbewehrten Betonen. Auf Grund von ausgeprägten Domänen hydratisierter Zementsteinphasen innerhalb des Rovings ergibt sich eine komplexe, multiskalige Verbundstruktur, die sich in ihren Eigenschaften deutlich von klassischen polymerbeschichteten Rovings unterscheidet. Wir diskutieren diesen Ansatz in Bezug auf Herstellung, nano-/mikroskopische Charakterisierung, sowie der mechanischen Eigenschaften der Probenkörper unter beschleunigten Alterungsbedingungen. Die mikroskopischen Untersuchungen mittels höchstauflösender Elektronenmikroskopie und Nanoindentation zielen darauf ab, die Grenzflächenanbindung, die veränderte Struktur in Abhängigkeit des verwendeten Polymers und der Additive sowie die Korrosionsmechanismen aufzuklären. / Hybrid surface modifications of glass fiber rovings with polymer/cement-composites allow the generation of extended cement phases within the roving and an activation of the innermost filaments to the surrounding concrete matrix. This enables enhanced load transfer across the full roving cross section when used as fibrous reinforcement in textile-reinforced concrete. Due to the presence of extended concrete domains within the roving, a complex multiscale composite structure develops, displaying distinctly different properties as compared to standard polymer impregnation routes. We discuss this approach in terms of production, nano/microscopic characterization of the concrete composites and mechanical properties of the resulting specimens under accelerated aging conditions. The microscopy studies using highest resolution electron microscopy and nanoindentation aim to elucidate the interface connection, the changes in morphology of the concrete as a function of the polymer and additives used, as well as shedding light on the corrosion mechanisms.
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Obtenção e caracterização de laminados de compósitos poliméricos híbridos de fibras de juta a partir de laminados de fibras de vidro utilizados na fabricação de pás eólicas / Obtaining and characterization of jute hybrid polymer composite from glass fiber reinforced polymer laminates used in wind blade manufacturingAlves, Jose Leandro Correia 29 May 2017 (has links)
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Previous issue date: 2017-05-29 / Não recebi financiamento / At last years due to increasing use of composite materials of synthetic fibers with thermosetting matrix, several alterative have been sought trying to minimize the impacts generated by both the dispose of this material at the end of their useful life and by its heavy dependency of non-renewable resources as petroleum based products for the production of raw materials. As alternative to introduce composites materials that have least environmentally impact natural fibers have drawn attention of researchers. In this work the aim is to manufacture by vacuum infusion process, composite laminates hybrid adding woven jute fiber in structural weaving fiberglass with epoxy resin matrix. The quality of laminate was analyzed by fiber weight fraction determining and thermal analysis by DSC (Differential Scanning Calorimetry) and DMTA (Dynamic Mechanical Thermal Analysis). It was possible to manufacture hybrids laminates by vacuum infusion with fiber fraction in about 60%. Hybrids laminates presented had a reduction of density of 20% with relation to the glass reinforced plastic. Regarding to mechanical properties, the laminates were characterized by tensile, compression and ILSS testing. With respect to hybrid laminates, the better results of tensile properties such as strength and young's modulus was achieved by the laminates with fiber oriented in 0/90° (H0/90) with maximum strength value near to 200 MPa, while for orientation ±45° (H45 e H45/0/90) the strength results were 68 MPa and 84 MPa, respectively. In this case can be highlighted the hybrid laminate H45, whose tensile strength (83,9 MPa) has not present significant changes with the introduction of jute fiber (with increase of 60% its thickness) compared with glass reinforced plastic (84,5 MPa) for the same fiber orientation. For compressive strength the best result was presented by the laminates H0/90 (fibers in 0/90°) as well, with values close to 150 MPa while the laminates to ±45° (H45 e H45/0/90) presented values of 90 MPa. Regarding to ILSS the variation of strength was smaller, 25 MPa to direction 0/90° and 23 MPa and 21 MPa to H45 and H45//0/90 laminates, respectively. Therefore, mechanical properties were significantly influenced by plies orientation in the laminates and by the hybridization with jute fibers. / Nos últimos anos, devido ao crescente consumo de compósitos de fibras sintéticas com matriz termorrígida, várias alternativas têm sido buscadas a fim de minimizar os impactos gerados tanto pelo descarte desse material ao fim de sua vida útil, quanto pela grande dependência de derivados de recursos não renováveis, como o petróleo para a produção das matérias-primas. Como uma das alternativas de introduzir na área de compósitos, materiais que tenham menores impactos ambientais, as fibras naturais têm recebido atenção de pesquisadores. Assim, neste trabalho foram moldados pelo processo de infusão à vácuo, compósitos de laminados híbridos através da utilização de tecidos de fibras de juta e tecidos estruturais de fibras de vidro com matriz de resina epóxi. A qualidade dos laminados foi analisada por meio da determinação da fração mássica de fibra e por análise térmica de DSC (Differential Scanning Calorimetry) e DMTA (Dynamic Mechanical Thermal Analysis. Foi possível moldar laminados híbridos pelo processo de infusão com fração de fibra em cerca de 60%. Os laminados híbridos apresentaram uma redução na densidade de 20% em relação aos compósitos contendo somente fibras de vidro. Em relação às propriedades mecânicas, os compósitos laminados foram caracterizados através dos ensaios de tração, compressão e cisalhamento interlaminar (ILSS). Entre os laminados híbridos, os melhores resultados de propriedades de tração, como resistência e módulo de elasticidade foram alcançados pelos laminados com ambas as fibras orientadas a 0/90° (H0/90), com valor de tensão máxima próximo a 200 MPa, enquanto que para as orientações ±45° (H45 e H45/0/90) os valores foram próximos de 68 e 84 MPa, respectivamente. No caso, pode ser destacado o laminado híbrido H45, cuja resistência a tração (83,9 MPa) não apresentou mudanças significativas com a introdução das fibras de juta (com acréscimo de 60% na espessura) quando comparado ao laminado de fibras de vidro (84,5 MPa) com mesma orientação. A melhor resistência à compressão também foi apresentada pelos laminados orientados a 0/90° (H0/90) com valores próximos a 150 MPa, enquanto os laminados a ±45° (H45 e H45/0/90) apresentaram os valores de 90 MPa. Em relação à resistência ao cisalhamento interlaminar, entre os laminados híbridos, a variação entre as orientações foi menor, 25 MPa para a direção 0/90° e, 23MPa e 21MPa para os laminados H45 e H45//0/90, respectivamente. Assim, as propriedades mecânicas foram influenciadas significativamente pela orientação das v camadas nos laminados e pela introdução das fibras de juta. Desta forma, conclui-se que a significativa redução de algumas propriedades possivelmente invalida a utilização das configurações híbridas estudadas para aplicações estruturais nas pás eólicas. No entanto, as configurações de laminados híbridos, desenvolvidas e analisadas neste trabalho podem ser aplicadas para moldar componentes em compósitos para peças não estruturais ou com menores requisitos de resistência, como para o segmento automotivo, e ainda com possibilidades de melhorias.
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EFEITO DO TIPO DE INSTRUMENTO E DA TÉCNICA OBTURADORA NA RESISTÊNCIA À FRATURA DE DENTES RESTAURADOS. / EFFECT OF THE INSTRUMENT TYPE AND ROOT CANAL FILLING TECHNIQUE ON FRACTURE RESISTANCE OF RESTORED ROOTSSantini, Manuela Favarin 03 March 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to assess the effect of instrument type (K-files and nickel-titanium rotary files) and the root canal filling technique (active and passive lateral condensation) on fracture resistance. Sixty eight teeth (canines and premolars) were divided into 4 groups (n=17): G1 - hand instrumentation and active lateral condensation; G2 - hand instrumentation and passive lateral condensation; G3 - rotary instrumentation and active lateral condensation; G4 - rotary instrumentation and passive lateral condensation. Before the filling, the roots were embedded in acrylic resin to simulate the periodontal ligament using a polyether impression material. Every root was restored with glass fiber post and metallic crown. The specimens were mechanical cycled (500.000 cycles, 45°, 37° C, 133 N, 2 Hz) and they were submitted to fracture test (45º, 1 mm/ min) until the fracture occurred. The Kruskal-Wallis test showed that the groups were not different from each other (p = 0. 247). In situations where an endodontic post is required, the instrument type and the obturation technique seem to have no influence on fracture resistance. / O objetivo deste estudo foi avaliar o efeito do tipo de instrumento (limas manuais tipo K e instrumentos rotatórios de NiTi) e da técnica obturadora (condensação lateral ativa e condensação lateral passiva) na resistência à fratura. Para isso, 68 dentes (caninos e pré-molares) foram divididos em 4 grupos (n=17): G1 - instrumentação manual e condensação lateral ativa; G2 - instrumentação manual e condensação lateral passiva; G3 - instrumentação rotatória e condensação lateral ativa; G4 - instrumentação rotatória e condensação lateral passiva. Antes da etapa obturadora, as raízes foram embutidas em resina acrílica para a simulação do ligamento periodontal com material de moldagem à base de poliéter. Todas as raízes foram restauradas com pino de fibra de vidro e coroa metálica. Os espécimes foram submetidos à ciclagem mecânica (500.000 ciclos, 45°, 37° C, 133 N, 2 Hz) e ao teste de resistência à fratura (45º, 1 mm/ min) até a falha ocorrer. O teste de Kruskal-Wallis mostrou que os grupos não foram diferentes entre si (p = 0, 247). Em situações em que há a necessidade de cimentação de pino intrarradicular, a escolha do tipo de instrumento e da técnica obturadora parece não ter influência na resistência à fratura.
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EFEITO DE SOLUÇÕES ATIVADAS POR ULTRASSOM NA RESISTÊNCIA ADESIVA DE PINOS DE FIBRA DE VIDRO CIMENTADOS COM CIMENTO RESINOSO AUTOADESIVO / EFFECT OF INTRACANAL IRRIGANTS ON BOND STRENGH OF FIBER POSTS CEMENTED WITH A SELF-ADHESIVE RESIN CEMENTBarreto, Mirela Sangoi 07 July 2015 (has links)
The current study aimed to evaluate the effect of irrigating and chelating solutions on bond
strength of fiber glass posts cemented with RelyX U200. 60 single-rooted premolars were
sectioned at 14 mm from the apex, prepared with ProTaper Universal system until F3
instrument and filled with F3 master cone and AH Plus sealer. Root canal filling was partially
removed, remaining 4 mm of guta-percha at the apical third. Specimens were randomly
divided into 5 experimental groups (n=12), according to the solution used before fiber post
cementation (dentin surface treatment), as described: EDTA 17% (EDTA); QMix (QM);
SmearClear (SC); NaOCl 2.5% (NaOCl) and saline solution as control group (SS). Ultrasonic
activation was performed three times, during 20 seconds each and root canals were dried with
paper points. Exacto N2 glass fiber posts were cemented with RelyX U200. Rhodamine B dye
was mixed to RelyX U200 in one specimen per group, in order to provide fluorescence for
confocal laser scanning microscopy (CLSM) assessment. A cutting machine was used for
root s sectioning, providing 3 slices, one for each root third. Next, push-out test was
performed. Stereomicroscope and CLSM were used to analyze the failure mode and to
illustrate the pattern of distribution of RelyX U200 inside dentinal tubules, respectively. Bond
strength mean were calculated and ANOVA and Bonferroni tests were used for statistical
analysis. SS showed the higher mean of bond strength values, superior to QM, SC (P < .05).
NaOCl presented intermediary bond strength values, similar to EDTA and SS (P > .05). QM
and SC showed the lowest mean of bond strength (P < .05). In conclusion, SS and NaOCl
associated to ultrasonic activation seems to be adequate solutions for root canal cleaning
before fiber post cementation with RelyX U200, while chelating solutions, such as EDTA,
QMix and SmearClear, should not be used for dentin pre-treatment when cementing with
RelyX U200. / O presente estudo tem por objetivo avaliar o efeito de diferentes soluções irrigantes e
quelantes na resistência adesiva de pinos de fibra de vidro cimentados com cimento
autoadesivo RelyX U200. 60 pré-molares inferiores extraídos de humanos, padronizados em
14 mm, foram preparados com o sistema ProTaper Universal até o instrumento F3, obturados
com cimento AH Plus e cones F3 do mesmo sistema. Os espécimes foram desobturados
parcialmente, restando 4 mm apicais de material obturador e realocados em quatro grupos
experimentais e um controle (n=12), de acordo com a solução de tratamento de superfície
dentinária prévia à cimentação dos pinos: EDTA 17% (EDTA), QMix (QM), SmearClear
(SC), Soro Fisiológico (SS) e NaOCl 2,5% (NaOCl). As soluções foram ativadas por
ultrassom em três etapas, durante 20 segundos cada e os canais foram secos com pontas de
papel absorventes. Os pinos de fibra de vidro do Sistema Exacto Translúcido N2 foram
cimentados com RelyX U200. Em um espécime por grupo foi incorporada Rodamina B ao
cimento autoadesivo como marcador fluorescente para análise em Microscopia Confocal à
laser (MECL). Foram seccionados 3slices por espécime, sendo 1 slice por terço radicular, e
submetidos ao teste de push-out na máquina de ensaio universal EMIC. Estereomicroscópio e
MECL foram utilizados para analisar o padrão de falha dos espécimes e o padrão de
penetração do cimento autoadesivo nos túbulos dentinários, respectivamente. A média de
resistência adesiva de cada espécime foi calculada. Testes ANOVA e Bonferroni foram
utilizados para analisar as diferenças entre os grupos. SS demonstrou a maior média de
resistência adesiva, sendo superior aos grupos QM, SC (P <.05). NaOCl apresentou valores
intermediários de resistência adesiva, similares ao EDTA e SS (P > .05). QM e SC
apresentaram as menores médias de resistência adesiva (P < .05). Pode-se concluir que o uso
de SS e NaOCl parece ser adequado para lavagem do canal prévia à cimentação de pinos de
fibra de vidro, com uso de cimento resinoso autoadesivo RelyX U200. O uso de soluções
quelantes como EDTA, QM e SC parece interferir negativamente nos valores de resistência
adesiva.
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Desenvolvimento de t?xteis t?cnicos para refor?o de comp?sitos polim?ricosLima, Jos? Henrique Batista 02 May 2012 (has links)
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Previous issue date: 2012-05-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / 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 / 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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Avalia??o da estrutura de tecidos t?cnicos como elemento refor?ante em comp?sitos polim?ricos sistema poli?ster isoft?licoMelo, Alan Jones Lira de 23 July 2013 (has links)
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Previous issue date: 2013-07-23 / Materials known as technical textiles can be defined as structures designed and
developed to meet specific functional requirements of various industry sectors, which is
the case in automotive and aerospace industries, and other specific applications.
Therefore, the purpose of this work presents the development and manufacture of
polymer composite with isophthalic polyester resin. The reinforcement of the composite
structure is a technical textile fabric made from high performance fibers, aramid (Kevlar
49) and glass fiber E. The fabrics are manufactured by the same method, with the aim of
improving the tensile strength of the resulting polymer composite material. The fabrics,
we developed some low grammage technical textile structures in laboratory scale and
differentiated-composition type aramid (100%), hybrid 1 aramid fiber / glass (65/35%)
and hybrid 2 aramid fiber / glass (85/15% ) for use as a reinforcing element in
composite materials with unsaturated isophthalic polyester matrix. The polymer
composites produced were tested in uniaxial tensile fracture surface and it?s evaluated
by SEM. The purpose of this work characterize the performance of polymer composites
prepared, identifying changes and based on resistance to strain corresponding to the
mechanical behavior. The objectives are to verify the capability of using this
reinforcement structure, along with the use of high performance fibers and resin in
terms of workability and mechanical strength; verify the adherence of the fiber to the
matrix and the fracture surface by electron microscopy scanning and determination of
tensile strength by tensile test. The results indicate that, in a comparative study to the
response of uniaxial tensile test for tensile strength of the composites and the efficiency
of the low percentage of reinforcement element, being a technical textile fabric structure
that features characteristic of lightness and low weight added in polymer composites / Os materiais denominados de tecidos 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 com aplica??es espec?ficas. Nesse sentido, este trabalho
apresenta o desenvolvimento e a fabrica??o de comp?sito polim?rico com resina
poli?ster isoft?lico. O refor?o do comp?sito ? uma estrutura de tecido t?xtil t?cnico
confeccionado com fibras de alto desempenho de aramida (Kevlar 49) e fibra de vidro
E. Os tecidos s?o fabricados pelo mesmo m?todo, com o objetivo do aprimorar a
resist?ncia a tra??o do material comp?sito polim?rico resultante. Os tecidos, foram
desenvolvidos em escala laboratorial com baixa gramatura e composi??o diferenciada
de aramida (100%), h?brido 1 fibra de aramida/vidro (65/35%) e h?brido 2 fibra de
aramida/vidro (85/15%) para utiliza??o como elemento refor?ante em comp?sitos com
matriz de poli?ster insaturada isoft?lico. Os comp?sitos polim?ricos produzidos foram
ensaiados em tra??o uniaxial e sua superf?cie de fratura avaliada por MEV. A proposta
do trabalho ? caracterizar o desempenho dos comp?sitos polim?ricos elaborados,
identificando as altera??es e baseando-se na resist?ncia ao ensaio de tra??o
correspondente a comportamento mec?nico. Os objetivos s?o verificar a potencialidade
da utiliza??o desta estrutura de refor?o, juntamente com a utiliza??o das fibras de alto
desempenho e a resina, em termos de trabalhabilidade e resist?ncia mec?nica; verificar a
ader?ncia da fibra ? matriz e a superf?cie de fratura atrav?s de microscopia eletr?nica de
varredura e determina??o de resist?ncia ? ruptura por ensaio de tra??o. Os resultados
indicam que, em um estudo comparativo para a resposta dos ensaios mec?nicos de
tra??o uniaxial h? resist?ncia ? ruptura dos comp?sitos e a efici?ncia da baixa
porcentagem do elemento de refor?o, sendo uma estrutura de tecido t?xtil t?cnico que
apresenta caracter?stica de leveza e baixa gramatura adicionada nos comp?sitos
polim?ricos
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