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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Fabrica??o de malha de trama utilizada como pr?-formas na ind?stria de comp?sitos e avalia??o das propriedades mec?nicas

Carvalho, Vladimir Anderson Marinho de 15 August 2008 (has links)
Made available in DSpace on 2014-12-17T14:57:51Z (GMT). No. of bitstreams: 1 VladimirAMC_capa_ate_cap2pdf.pdf: 1064881 bytes, checksum: ad3fb45b35e0f929ffd17f2ade8f17c2 (MD5) Previous issue date: 2008-08-15 / In the manufacture of composite, textile materials are being used as reinforcement. Generally, the combination of the matrix with the textile material in the form of fibres or yarns is used depending on their distribution in the web. In the present work, in place of fibres or yarns, a knitted structure in the form of the final product which is defined as preform. The preform is weft knit manufactured with polyester filaments. In the manufacture of composite, polyester resin was used as matrix. The physical and mechanical properties as well as the formability of the weft knit were analysed. The physical and mechanical properties as well as the formability of the knitted structure were analysed. The results obtained on the analysis show that the courses and wales of the weft knit structure and the tensile properties help the formability of the structure and the impregnation of the resin. It could be clearly observed that composite structure in the direction of the courses support more tension than in the direction of the wales. In relation to the three points flexural tests it was possible to note that there was more flexion in the direction of wales, what was expected. It was also possible to note that there are other advantages such as reduction in the loss of materials used, homogeneity in the distribution of the knitted structure in the mould, reduction in the preparation time and also in the reduction in the cost of manufacture / Na fabrica??o de comp?sitos, resultados da jun??o da resina como matriz e o material t?xtil como refor?o, o material t?xtil usualmente utilizado como refor?o, est? no formato de filamentos ou fibras soltas, que s?o aplicados diretamente sobre um molde, essa distribui??o aleat?ria do material pode ocasionar pontos fracos na estrutura j? que n?o garante uma distribui??o homogenia. No presente trabalho, em vez de fios ou fibras, foi utilizada uma malha t?xtil, fabricada na forma do produto final, que defini-se como pr?-forma, melhorando a distribui??o do material sobre o molde,. Esta pr?-forma foi fabricada em malha de trama (malha Jersey) com filamento de poli?ster e a resina de poli?ster foi utilizada como matriz na fabrica??o desse comp?sito. As propriedades f?sicas, mec?nicas e formabilidade das la?adas foram analisadas. Os resultados das propriedades da malha Jersey estudadas mostram que as la?adas da malha e as propriedades tensil ajudam a formabilidade da estrutura e a facilitam a impregna??o da resina. Claramente pode-se observar que a estrutura de comp?sito na dire??o de coluna suporta maior tens?o em compara??o com a estrutura na dire??o da carreira. Com rela??o ao teste de flex?o de tr?s pontos, foi poss?vel verificar maior flex?o no sentido da carreira, o que foi esperado. Foi poss?vel pontuar tamb?m outras vantagens como a redu??o de perdas de materiais, homogeneidade na distribui??o da estrutura de malha no molde, redu??o do tempo de produ??o e barateamento nos custos produtivos

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