Hybridization effect on mechanical properties of composite laminates
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.6/13013 |
Resumo: | Composite materials are increasingly being used in the aeronautical industry. Although carbon fibers are the strongest and most used in the aeronautical sector, these fibers collapse quite suddenly due to their fragile nature leading to catastrophic damage. In order to minimize this effect, an alternative technique is used, which consists of combining these fibers with another less fragile type, such as Kevlar fiber, in order to obtain a material with a more ductile behavior. As the viscoelastic behavior is not much discussed in the available open literature, this work intends to study this mechanical property in several hybrid composites involving carbon, kevlar and glass fibers. For a better understanding of this phenomenon, the static behavior and tenacity of these materials were also studied. For this purpose, the effect of hybridization on flexural properties, interlaminar shear strength, creep and stress relaxation was studied in eighteen hybrid combinations combined with an epoxy matrix. It was observed that hybridization can create a more tenacious and balanced composite. The stacking sequence has a significant influence on the mechanical properties of laminates. As such, for all mechanical tests, carbon fibers are better in compression if hybridized with kevlar and better in tension if hybridized with glass. Glass fibers have always performed better under compression and kevlar fibers always perform better under tension, regardless of which other fiber they are hybridized to. With these positions in the laminate, the composites achieve greater tension and stiffness, but less deformation, greater interlaminar shear strength, less creep and less stress relaxation. As for the number of fiber layers, in the bending properties, a lower percentage of kevlar in the laminate results in higher bending stress and interlaminar shear strength. However, for the viscoelastic behavior of hybrid composites, the number of layers has no direct influence on the creep and stress relaxation values, since molecular rearrangements occur. In addition, a study of the bending properties for different strain rates in carbon fiber composites and fiberglass composites was carried out. In this way, it could be shown that there is a relationship between the strain rate and the flexural stress and stiffness of the composites. As the strain rate increases, there is an increase in bending stress and stiffness. |
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Hybridization effect on mechanical properties of composite laminatesFibra de CarbonoFibra de KevlarFibra de VidroFluênciaHibridizaçãoPropriedades de FlexãoRelaxamento de TensãoResistência ao Cisalhamento InterlaminarTaxa de DeformaçãoDomínio/Área Científica::Engenharia e Tecnologia::Engenharia AeronáuticaComposite materials are increasingly being used in the aeronautical industry. Although carbon fibers are the strongest and most used in the aeronautical sector, these fibers collapse quite suddenly due to their fragile nature leading to catastrophic damage. In order to minimize this effect, an alternative technique is used, which consists of combining these fibers with another less fragile type, such as Kevlar fiber, in order to obtain a material with a more ductile behavior. As the viscoelastic behavior is not much discussed in the available open literature, this work intends to study this mechanical property in several hybrid composites involving carbon, kevlar and glass fibers. For a better understanding of this phenomenon, the static behavior and tenacity of these materials were also studied. For this purpose, the effect of hybridization on flexural properties, interlaminar shear strength, creep and stress relaxation was studied in eighteen hybrid combinations combined with an epoxy matrix. It was observed that hybridization can create a more tenacious and balanced composite. The stacking sequence has a significant influence on the mechanical properties of laminates. As such, for all mechanical tests, carbon fibers are better in compression if hybridized with kevlar and better in tension if hybridized with glass. Glass fibers have always performed better under compression and kevlar fibers always perform better under tension, regardless of which other fiber they are hybridized to. With these positions in the laminate, the composites achieve greater tension and stiffness, but less deformation, greater interlaminar shear strength, less creep and less stress relaxation. As for the number of fiber layers, in the bending properties, a lower percentage of kevlar in the laminate results in higher bending stress and interlaminar shear strength. However, for the viscoelastic behavior of hybrid composites, the number of layers has no direct influence on the creep and stress relaxation values, since molecular rearrangements occur. In addition, a study of the bending properties for different strain rates in carbon fiber composites and fiberglass composites was carried out. In this way, it could be shown that there is a relationship between the strain rate and the flexural stress and stiffness of the composites. As the strain rate increases, there is an increase in bending stress and stiffness.Os materiais compósitos estão cada vez mais a ser utilizados na indústria aeronáutica. Apesar das fibras de carbono serem as mais resistentes e as mais usadas no setor aeronáutico, estas fibras colapsam de maneira bastante repentina devido a sua natureza frágil levando a danos catastróficos. Com o intuito de minimizar este efeito utilizase uma técnica alternativa que consiste em combinar estas fibras com outro tipo menos frágil, como por exemplo a fibra de kevlar, de modo a obterem material com um comportamento mais dúctil. Como o comportamento viscoelástico não é muito abordado na literatura aberta disponível, este trabalho pretende então estudar esta propriedade mecânica em vários compósitos híbridos envolvendo fibras de carbono, kevlar e vidro. Para o melhor entendimento deste fenómeno estudouse igualmente o comportamento estático e tenacidade destes materiais. Para este propósito, o efeito da hibridização nas propriedades de flexão, resistência ao cisalhamento interlaminar, fluência e relaxamento de tensões foi estudado em dezoito combinações hibridas combinadas com uma matriz epoxídica. Observouse que a hibridização pode criar um compósito mais tenaz e balanceado. A sequência de empilhamento tem uma influência significativa nas propriedades mecânicas dos laminados. Como tal, para todos os testes mecânicos, as fibras de carbono são melhores na compressão se hibridizadas com kevlar e melhores em tensão se hibridizadas com vidro. As fibras de vidro sempre apresentaram melhores resultados sob compressão e as fibras de kevlar sempre apresentam melhores resultados sob tensão, independentemente da outra fibra com a qual são hibridizadas. Com essas posições no laminado, os compósitos alcançam maior tensão e rigidez, mas menor deformação, maior resistência ao cisalhamento interlaminar, menor fluência e menor relaxamento de tensão. Quanto ao número de camadas de fibras, nas propriedades de flexão, uma menor percentagem de kevlar no laminado resulta em maior tensão de flexão e resistência ao cisalhamento interlaminar. Porém, para o comportamento viscoelástico dos compósitos híbridos, o número de camadas não tem influência direta nos valores de fluência e relaxamento de tensão, uma vez que ocorrem rearranjos moleculares. Além disso, foi feito um estudo das propriedades de flexão para diferentes taxas de deformação em compósitos de fibra de carbono e compósitos de fibra de vidro. Desta forma, pôdese mostrar que existe uma relação entre a taxa de deformação e a tensão de flexão e rigidez dos compósitos. Com o aumento da taxa de deformação, ocorre um aumento da tensão de flexão e da rigidez.Reis, Paulo Nobre Balbis dosuBibliorumMonjon, Alice Marie Albina Michel2023-02-20T09:25:06Z2022-03-252022-01-262022-03-25T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.6/13013TID:203225406enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-12-15T09:56:26Zoai:ubibliorum.ubi.pt:10400.6/13013Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T00:52:32.049394Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Hybridization effect on mechanical properties of composite laminates |
title |
Hybridization effect on mechanical properties of composite laminates |
spellingShingle |
Hybridization effect on mechanical properties of composite laminates Monjon, Alice Marie Albina Michel Fibra de Carbono Fibra de Kevlar Fibra de Vidro Fluência Hibridização Propriedades de Flexão Relaxamento de Tensão Resistência ao Cisalhamento Interlaminar Taxa de Deformação Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica |
title_short |
Hybridization effect on mechanical properties of composite laminates |
title_full |
Hybridization effect on mechanical properties of composite laminates |
title_fullStr |
Hybridization effect on mechanical properties of composite laminates |
title_full_unstemmed |
Hybridization effect on mechanical properties of composite laminates |
title_sort |
Hybridization effect on mechanical properties of composite laminates |
author |
Monjon, Alice Marie Albina Michel |
author_facet |
Monjon, Alice Marie Albina Michel |
author_role |
author |
dc.contributor.none.fl_str_mv |
Reis, Paulo Nobre Balbis dos uBibliorum |
dc.contributor.author.fl_str_mv |
Monjon, Alice Marie Albina Michel |
dc.subject.por.fl_str_mv |
Fibra de Carbono Fibra de Kevlar Fibra de Vidro Fluência Hibridização Propriedades de Flexão Relaxamento de Tensão Resistência ao Cisalhamento Interlaminar Taxa de Deformação Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica |
topic |
Fibra de Carbono Fibra de Kevlar Fibra de Vidro Fluência Hibridização Propriedades de Flexão Relaxamento de Tensão Resistência ao Cisalhamento Interlaminar Taxa de Deformação Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica |
description |
Composite materials are increasingly being used in the aeronautical industry. Although carbon fibers are the strongest and most used in the aeronautical sector, these fibers collapse quite suddenly due to their fragile nature leading to catastrophic damage. In order to minimize this effect, an alternative technique is used, which consists of combining these fibers with another less fragile type, such as Kevlar fiber, in order to obtain a material with a more ductile behavior. As the viscoelastic behavior is not much discussed in the available open literature, this work intends to study this mechanical property in several hybrid composites involving carbon, kevlar and glass fibers. For a better understanding of this phenomenon, the static behavior and tenacity of these materials were also studied. For this purpose, the effect of hybridization on flexural properties, interlaminar shear strength, creep and stress relaxation was studied in eighteen hybrid combinations combined with an epoxy matrix. It was observed that hybridization can create a more tenacious and balanced composite. The stacking sequence has a significant influence on the mechanical properties of laminates. As such, for all mechanical tests, carbon fibers are better in compression if hybridized with kevlar and better in tension if hybridized with glass. Glass fibers have always performed better under compression and kevlar fibers always perform better under tension, regardless of which other fiber they are hybridized to. With these positions in the laminate, the composites achieve greater tension and stiffness, but less deformation, greater interlaminar shear strength, less creep and less stress relaxation. As for the number of fiber layers, in the bending properties, a lower percentage of kevlar in the laminate results in higher bending stress and interlaminar shear strength. However, for the viscoelastic behavior of hybrid composites, the number of layers has no direct influence on the creep and stress relaxation values, since molecular rearrangements occur. In addition, a study of the bending properties for different strain rates in carbon fiber composites and fiberglass composites was carried out. In this way, it could be shown that there is a relationship between the strain rate and the flexural stress and stiffness of the composites. As the strain rate increases, there is an increase in bending stress and stiffness. |
publishDate |
2022 |
dc.date.none.fl_str_mv |
2022-03-25 2022-01-26 2022-03-25T00:00:00Z 2023-02-20T09:25:06Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
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masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.6/13013 TID:203225406 |
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http://hdl.handle.net/10400.6/13013 |
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eng |
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eng |
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