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Thèse de Doctorat
DOI
https://doi.org/10.11606/T.88.2005.tde-10062005-184350
Document
Auteur
Nom complet
Ricardo Fernandes Carvalho
Unité de l'USP
Domain de Connaissance
Date de Soutenance
Editeur
São Paulo, 2005
Directeur
Jury
Calil Junior, Carlito (Président)
Demarzo, Mauro Augusto
Dias, Antonio Alves
Sales, Almir
Sousa, José Alexandrino de
Titre en portugais
"Compósitos de fibras de sisal para uso em reforço de estruturas de madeira"
Mots-clés en portugais
compósitos
madeira
reforço
sisal
Resumé en portugais
O reforço em estruturas de madeira é necessário em vários edifícios com interesse cultural e histórico. Compósitos com fibra têm sido utilizados no reforço de elementos estruturais de madeira. Carbono e fibras de vidro são as fibras mais usadas como reforço. Porém, fibras naturais são uma importante alternativa considerando as seguintes vantagens: abundância, biodegradabilidade e o baixo custo comparadas com as fibras de vidro ou fibras de carbono. As fibras têxteis e os fios de sisal foram caracterizados por ensaios de tração. Um novo tecido de sisal industrializado foi desenvolvido com base nos tecidos usados em compósitos estruturais com o objetivo de melhorar o alinhamento das fibras e reduzir as deformações transversais. Ensaios de tração foram utilizados para avaliar os compósitos de sisal com matrizes epóxi e poliuretanas derivadas do óleo de mamona. Os ensaios de flexão e cisalhamento foram utilizados para avaliar a resistência e a rigidez. Também foram analisadas as interfaces entre a madeira e os compósitos e avaliados os modos de ruptura. Os resultados mostraram que os compósitos de epóxi e sisal são suficientemente rígidos e resistentes para reforçar estruturas de madeira.
Titre en anglais
Sisal composites to reinforcement of timber structures.
Mots-clés en anglais
composite
reinforcement
sisal
timber
Resumé en anglais
Many buildings of cultural and historical interest require reinforcement of their timber structures. This research focuses on fiber-reinforced composites to repair and reinforce such structural elements of wood as an alternative for carbon and glass fibers, which are the materials most commonly used for purposes of reinforcement. Natural fibers are an important alternative, offering several advantages such as their abundant availability, biodegradability and low cost compared with glass or carbon fibers. Sisal In the study reported here, textile sisal fibers and cords were characterized under tensile testing. A new sisal textile was designed based on an industrially manufactured textile for advanced composite arrangements to improve the fibers’ alignment and reduce transverse deformations. Composites consisting of a combination of sisal, commercial epoxy and polyurethane based on castor oil resin matrixes were tensile tested. The effect of sodium hydroxide (10%) treatments on the sisal was also evaluated. The composite material was subjected to bending and shear tests to determine its strength and stiffness, and its wood-composite interface and failure modes were investigated. The results showed that the new Sisal Fiber-Reinforced Plastic (SFRP) is sufficiently strong and stiff to serve as a reinforcement of timber structures.
 
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tesericardo.pdf (2.28 Mbytes)
Date de Publication
2005-08-04
 
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