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Efeito da temperatura no comportamento de compósitos de resina epóxi nano reforçados com nano fibras de carbono
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| Documento em Acesso Embargado até dia 10-10-2026. Tente solicitar cópia ao autor carregando no ficheiro | 3.54 MB | Adobe PDF |
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A indústria aeronáutica tem se destacado como um fator crucial no desenvolvimento tecnológico, impulsionada pela inovação em compósitos. Os compósitos, especialmente os reforçados com fibras de carbono e nano materiais, têm revolucionado o design e a fabricação de aeronaves, oferecendo melhorias significativas em termos de leveza, resistência e durabilidade. Neste contexto, realizou-se esta dissertação com o prepósito de investigar o efeito da temperatura no comportamento de compósitos de resina epóxi reforçada com nano fibras de carbono (CNF’s), por meio de um estudo numérico e experimental. Visa entender como as variações térmicas afetam as propriedades mecânicas e térmicas desses compósitos avançados, essenciais para aplicações na indústria aeroespacial e aeronáutica. A metodologia utilizada foi a agitação mecânica e a moldação manual de fácil aplicação, custos reduzidos e facilmente escalável para a indústria. Os ensaios de flexão realizados evidenciaram que tanto as matrizes quanto os laminados aditivados com 0,75% em peso de CNF’s apresentaram desempenho superior em relação às respetivas amostras de controlo. A 50 ?, a incorporação de CNF’s na matriz promoveu um aumento de 42,34% na tensão de flexão, um incremento de 44,33% na rigidez e uma redução de 5,77% na deformação, quando comparada à matriz de controlo. Para os laminados submetidos à mesma condição térmica, a adição de 0,75% em peso de CNF’s resultou em um acréscimo de 17,75% na tensão de flexão, um ganho de 5,35% na rigidez e uma diminuição de 7,09% na deformação, em relação ao laminado de controlo. Nos testes de relaxação de tensões, ocorre a redução da tensão ao longo do tempo, e em termos de fluência, o deslocamento aumenta ao longo do tempo e os dados experimentais foram ajustados com sucesso pelo modelo de Kohlrausch-Williams-Watts (KWW).
The aeronautical industry has stood out as a crucial factor in technological development, driven by innovation in composites. Composites, especially those reinforced with carbon fibers and nanomaterials, have revolutionized aircraft design and manufacturing, offering significant improvements in terms of lightness, strength, and durability. In this context, this dissertation was conducted with the purpose of investigating the effect of temperature on the behavior of epoxy resin composites reinforced with carbon nanofibers (CNF`s), through a numerical and experimental study. It aims to understand how thermal variations affect the mechanical and thermal properties of these advanced composites, which are essential for applications in the aerospace and aeronautical industries. The methodology used was mechanical agitation and manual molding, which is easy to apply, low cost, and easily scalable for industry. The flexural tests showed that both the matrices and the laminates with 0.75% CNF weight addition performed better than the respective control samples. At 50°C, the incorporation of CNFs into the matrix promoted a 42.34% increase in flexural stress, a 44.33% increase in stiffness, and a 5.77% reduction in deformation when compared to the control matrix. For laminates subjected to the same thermal condition, the addition of 0.75% by weight of CNFs resulted in a 17.75% increase in flexural stress, a 5.35% gain in stiffness, and a 7.09% decrease in deformation compared to the control laminate. In stress relaxation tests, stress decreases over time, and in terms of creep, displacement increases over time, and the experimental data were successfully fitted by the KohlrauschWilliams-Watts (KWW) model.
The aeronautical industry has stood out as a crucial factor in technological development, driven by innovation in composites. Composites, especially those reinforced with carbon fibers and nanomaterials, have revolutionized aircraft design and manufacturing, offering significant improvements in terms of lightness, strength, and durability. In this context, this dissertation was conducted with the purpose of investigating the effect of temperature on the behavior of epoxy resin composites reinforced with carbon nanofibers (CNF`s), through a numerical and experimental study. It aims to understand how thermal variations affect the mechanical and thermal properties of these advanced composites, which are essential for applications in the aerospace and aeronautical industries. The methodology used was mechanical agitation and manual molding, which is easy to apply, low cost, and easily scalable for industry. The flexural tests showed that both the matrices and the laminates with 0.75% CNF weight addition performed better than the respective control samples. At 50°C, the incorporation of CNFs into the matrix promoted a 42.34% increase in flexural stress, a 44.33% increase in stiffness, and a 5.77% reduction in deformation when compared to the control matrix. For laminates subjected to the same thermal condition, the addition of 0.75% by weight of CNFs resulted in a 17.75% increase in flexural stress, a 5.35% gain in stiffness, and a 7.09% decrease in deformation compared to the control laminate. In stress relaxation tests, stress decreases over time, and in terms of creep, displacement increases over time, and the experimental data were successfully fitted by the KohlrauschWilliams-Watts (KWW) model.
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Compósitos poliméricos Resina epóxi Nano fibras de carbono Efeito da temperatura Ensaios mecânicos Polymeric Composites Epoxy resin Carbon nanofibers Temperature effect Mechanical Characterization