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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

[pt] EFEITOS DO ENVELHECIMENTO EM ÁGUA E ÓLEO LUBRIFICANTE SOBRE O COMPORTAMENTO À FLUÊNCIA DE MATERIAL COMPÓSITO DE MATRIZ POLIMÉRICA REFORÇADA POR FIBRA DE VIDRO / [en] EFFECTS OF AGING IN WATER AND LUBRICATING OIL ON THE CREEP BEHAVIOR OF POLYMER MATRIX COMPOSITE REINFORCED WITH GLASS FIBER

LUCIO ROSSI DE SOUZA 20 July 2016 (has links)
[pt] Esse estudo tem como objetivo verificar as consequências do envelhecimento no comportamento à fluência de um material compósito reforçado por fibras de vidro, em função de diferentes tipos de envelhecimento e temperaturas de ensaio. Para tanto, corpos de prova envelhecidos em água e óleo, bem como outros sem qualquer envelhecimento, foram ensaiados à fluência em 25 graus Celsius e 60 graus Celsius. As análises se basearam nas propriedades mecânicas relativas ao processo de fluência obtidas tanto experimentalmente quanto a partir de modelos viscoelásticos e semiempíricos. Dentre as condições experimentais empregadas, o parâmetro que mais influenciou o processo de fluência foi a temperatura. Os efeitos da temperatura no processo de fluência foram determinantes inclusive para a escolha do modelo que melhor se ajustou aos pontos experimentais. Na temperatura de 25 graus Celsius, independente do meio ou tempo de envelhecimento, o modelo de melhor ajuste foi o de Potência, enquanto que na temperatura de 60 graus Celsius, o modelo de Andrade foi o que melhor se ajustou aos pontos experimentais. No entanto, observou-se, também, que os diversos tipos de envelhecimentos alteraram algumas propriedades, como o módulo de Young. / [en] The objective of this work is to verify the consequences of ageing on the creep deformation behavior of a fiberglass composite material, as a function of various combinations of ageing means, ageing times, and test temperatures. For this purpose, samples aged in water and oil, as well as samples not aged at all, were tested to creep deformation at 25 Celsius Degree and 60 Celsius Degree. The results analysis were based on mechanical properties, related to the creep deformation process, obtained both directly from the experiments and from viscoelastic and semi-empirical mathematical models. From all the experimental conditions used on this work, the one that most influenced the creep deformation process was temperature. The effects of temperature on the creeping process, that they were even decisive to select the best fitting model for the experimental data. For the 25 Celsius Degree tests, regardless of ageing mean or time, the mathematical model that best fitted the data was the Power model, as for the 60 Celsius Degree tests, the best model to fit the experimental data was Andrade. However, it was noticed that ageing by itself was also capable of changing some mechanical properties, as Young modulus, for example.

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