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Advisor(s)
Abstract(s)
Este trabalho insere-se no âmbito das ligações adesivas que, apesar de ser um processo de ligação utilizado há milhares de anos, tem sofrido nos últimos tempos um grande incremento na sua aplicação nas mais diversas indústrias. Tal deve-se ao desenvolvimento de novos adesivos e às vantagens associadas a este processo de ligação como, por exemplo, melhor distribuição de tensões, resistência à fadiga, capacidade de ligar materiais similares e dissimilares, resistência à corrosão, não danifica nem provoca alterações estruturais dos substratos e permite uma redução do peso das estruturas. Esta dissertação desenvolveu-se no
Instituto Superior de Engenharia do Porto e teve como principal objetivo dotar o Laboratório de Ensaios Tecnológicos das ferramentas necessárias para a realização de ensaios de arrancamento por rolete flutuante e ensaios de tração de juntas topo a topo. Numa primeira fase do trabalho foi realizado um breve estudo sobre as ligações adesivas e depois centrou-se no desenvolvimento das referidas ferramentas. A ferramenta para o ensaio de rolete flutuante está de acordo com a norma ASTM D3167. Para o fabrico das juntas topo a topo optou-se por desenvolver uma ferramenta original e, portanto, diferente da ferramenta frequentemente
utilizada e que é proposta na norma ASTM D2095. Esta ferramenta é necessária para garantir o alinhamento dos substratos e regular a espessura do adesivo. Além disso, foi também necessário desenvolver um dispositivo para fixar e tracionar a junta topo a topo na máquina de tração. Para validar o funcionamento das ferramentas foram realizados os respetivos ensaios de arrancamento e de tração, utilizando três adesivos com diferentes valores de rigidez, ductilidade e resistência mecânica. Dois dos adesivos são de epóxido (Araldite® AV138 e Araldite® 420A/B) e o outro é de poliuretano (SikaForce® 710). A execução dos ensaios e as
propriedades avaliadas permitiram constatar o correto funcionamento das ferramentas desenvolvidas e fabricadas no âmbito deste trabalho.
This work inserts into the scope of adhesive bonds that, despite being a bonding process used for thousands of years, has suffered in recent times a large increase in its applications in the most diverse industries. This is due to the development of new adhesives and associated advantages with this bonding process such as, for example, better stress distribution, fatigue resistance, capacity to bond similar and dissimilar materials, corrosion resistance, does not damage or cause structural changes of the substrates and allows weight reduction of structures. This dissertation was developed at the Instituto Superior de Engenharia do Porto and its main objective was to provide the Technological Testing Laboratory with the necessary tools to realize floating roller peel tests and tensible tests of butt-joints. In the first phase of the work, a brief study was done about adhesive connections and then focused on the development of these tolls. The floating roller tool complies with the ASTM D3167 standard. The manufacture of butt-joints, it was decided to develop an original tool and, therefore, different from the frequently used tool proposed in the ASTM D2095 standard. This tool is necessary to ensure substrate alignment and regulate adhesive thickness. Furthermore, it was also necessary to develop a device to fix and pull the butt-joint on the tensible machine. To validate the performance of the tools, the respective peel and tensible tests were realized, using three adhesives with different values of stiffness, ductility and mechanical resistance. Two of the adhesives are epoxy (Araldite® AV138 and Araldite® 420A/B) and the other is polyurethane (SikaForce® 710). The execution of the tests and the evaluated properties made it possible to verify the correct functioning of the tools developed and manufactured within the scope of this work.
This work inserts into the scope of adhesive bonds that, despite being a bonding process used for thousands of years, has suffered in recent times a large increase in its applications in the most diverse industries. This is due to the development of new adhesives and associated advantages with this bonding process such as, for example, better stress distribution, fatigue resistance, capacity to bond similar and dissimilar materials, corrosion resistance, does not damage or cause structural changes of the substrates and allows weight reduction of structures. This dissertation was developed at the Instituto Superior de Engenharia do Porto and its main objective was to provide the Technological Testing Laboratory with the necessary tools to realize floating roller peel tests and tensible tests of butt-joints. In the first phase of the work, a brief study was done about adhesive connections and then focused on the development of these tolls. The floating roller tool complies with the ASTM D3167 standard. The manufacture of butt-joints, it was decided to develop an original tool and, therefore, different from the frequently used tool proposed in the ASTM D2095 standard. This tool is necessary to ensure substrate alignment and regulate adhesive thickness. Furthermore, it was also necessary to develop a device to fix and pull the butt-joint on the tensible machine. To validate the performance of the tools, the respective peel and tensible tests were realized, using three adhesives with different values of stiffness, ductility and mechanical resistance. Two of the adhesives are epoxy (Araldite® AV138 and Araldite® 420A/B) and the other is polyurethane (SikaForce® 710). The execution of the tests and the evaluated properties made it possible to verify the correct functioning of the tools developed and manufactured within the scope of this work.
Description
Keywords
Butt-joint Peel test Tensible test Adhesive joints Failure modes Ligação adesiva Ensaio de rolete flutuante Ensaio de tração de juntas topo a topo Propriedades mecânicas dos adesivos Modos de rotura