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Abstract(s)
O crescimento no consumo de materiais compósitos denota a procura incessante de materiais e metodologias cada vez mais eficientes e sustentáveis na indústria. Nesta busca, os compósitos de matriz polimérica apresentam propriedades físicas elevadas ao nível da resistência mecânica, química e física, aliadas a um peso reduzido. Isto torna-os particularmente interessantes para a utilização em estruturas que necessitem de elevada resistência aliada ao menor peso possível.
A produção de estruturas complexas com materiais compósitos obriga à adição de juntas estruturais. Isto torna necessário conhecer e desenvolver processos de ligação eficientes, uma vez que uma junta é uma zona de fragilidade na estrutura.
A utilização emergente de compósitos de matriz termoplástica em estruturas complexas abriu portas para novos processos de ligação. Este tipo de material, dada a sua capacidade de reprocessamento por aquecimento, permite a utilização de processos de soldadura análogos aos processos já utilizados na indústria dos polímeros termoplásticos.
Visto isto, e no intuito de explorar as potencialidades do processo de soldadura e do material compósito termoplástico, procedeu-se à realização desta dissertação.
A dissertação apresentada pretendeu estudar o processo de ligação por soldadura de um compósito de polipropileno reforçado com fibra de vidro. Para isto, foi realizado um procedimento experimental com base na norma ASTM D1002, sendo calculado também o tempo de estágio e temperatura de processamento importantes. De forma a comparar este procedimento com uma ligação mais comum, foi realizado também um programa experimental de ligação adesiva com o mesmo compósito.
Foram realizados ensaios de tração aos provetes ligados de forma a determinar a tensão de corte máxima admissível. Os resultados obtidos demonstraram as potencialidades do processo de soldadura face ao processo de ligação adesiva em compósitos termoplásticos.
The growth on composite material consumption shows the industry incessante search for increasable sustainable and efficient materials and methods. In this search, polymeric matrix composites show high physical, chemical and mechanical proprieties, allied with reduced mass. This makes them particularly interesting on structures for high resistance with minimal weight. The manufacturing of complex structures using composite materials leads to the use of structural joints. This requires the knowledge and development of eficiente bonding processes, because a joint is a frail zone on the structure. The emergent use of thermoplastic composites in complex structures opens paths to new bonding and fabrication processes. This type of material, given its reprocessing capabilities using heat, allows the use of processes similar to the processes already used on the thermoplastic polymer industry. This dissertation was developed in order to explore the potential of this type of process and the thermoplastic composite. The presented dissertation pretended the study of the fusion bonding process in a composite of polypropylene reinforced with glass fibers. An experimental procedure developed using the ASTM D1002 standard, while calculating a heat fabrication time for important processing temperatures. In order to compare this procedure with a more common bonding process, an adhesive bonding procedure was also created. The test subjects were tested by tension loading them in order to determine the maximum shear strength. The results obtained were satisfactory and show the potential of the bonding process relative to adhesive bonding in thermoplastic composites.
The growth on composite material consumption shows the industry incessante search for increasable sustainable and efficient materials and methods. In this search, polymeric matrix composites show high physical, chemical and mechanical proprieties, allied with reduced mass. This makes them particularly interesting on structures for high resistance with minimal weight. The manufacturing of complex structures using composite materials leads to the use of structural joints. This requires the knowledge and development of eficiente bonding processes, because a joint is a frail zone on the structure. The emergent use of thermoplastic composites in complex structures opens paths to new bonding and fabrication processes. This type of material, given its reprocessing capabilities using heat, allows the use of processes similar to the processes already used on the thermoplastic polymer industry. This dissertation was developed in order to explore the potential of this type of process and the thermoplastic composite. The presented dissertation pretended the study of the fusion bonding process in a composite of polypropylene reinforced with glass fibers. An experimental procedure developed using the ASTM D1002 standard, while calculating a heat fabrication time for important processing temperatures. In order to compare this procedure with a more common bonding process, an adhesive bonding procedure was also created. The test subjects were tested by tension loading them in order to determine the maximum shear strength. The results obtained were satisfactory and show the potential of the bonding process relative to adhesive bonding in thermoplastic composites.
Description
Keywords
Materiais compósitos Termoplásticos Ligação adesiva Ligação soldada Termoplástico Fibra de vidro Composite materials Thermoplastics Adhesive bonding Fusion bonding Thermoplastic Fiberglass