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Advisor(s)
Abstract(s)
Atualmente, as ligações adesivas são muito utilizadas no projeto de estruturas mecânicas, em detrimento das ligações mecânicas clássicas, nomeadamente as ligações aparafusadas ou rebitadas. A escolha das ligações adesivas em projeto dá-se por estas permitirem uma distribuição mais uniforme de tensões e a redução do peso da estrutura, possibilitarem a ligação de materiais diferentes e, atualmente, existirem métodos numéricos fiáveis de previsão da resistência de juntas adesivas, o que diminui os custos associados ao sobredimensionamento antes feito devido à falta de informações sobre as ligações adesivas. O ensaio de arrancamento T-peel é muito utilizado, pois possui fácil reprodução, baixo custo e pode ser realizado em máquinas de ensaios universais. O ensaio floating roller peel é utilizado na indústria para avaliar a qualidade da adesão de juntas adesivas, pois submete a junta adesiva a condições extremas de solicitação. O presente trabalho tem como objetivo caracterizar a resistência ao arrancamento do adesivo estrutural Araldite® AV138 aplicado em juntas adesivas fabricadas com aderentes de naturezas diferentes através da modelação numérica do ensaio floating roller peel. Foram utilizadas juntas adesivas fabricadas com o polímero reforçado com fibra de carbono (PRFC) e a liga de alumínio (AW 6082-T651). O modelo numérico foi baseado em modelos de dano coesivo (MDC) aplicados no software ABAQUS®. Para modelar de forma fiável o contacto entre os aderentes e os roletes de fixação, estes últimos foram incluídos nos ensaios e estabelecidas as condições de contacto e conexões respetivas. Para validar e confirmar a fiabilidade dos resultados obtidos através do ensaio numérico floating roller peel, as previsões obtidas foram comparadas com resultados experimentais previamente estabelecidos. Os resultados indicaram que a modelação numérica utilizada permitiu reproduzir o comportamento físicos dos ensaios experimentais e permitiu prever com rigor a resistência ao arrancamento do adesivo estrutural Araldite® AV138.
Currently, adhesive joints are widely used in the design of mechanical structures, to the detriment of classical mechanical joints, namely bolted or riveted. The choice of adhesive joints in design is due to the more uniform distribution of stresses and reduction of structural weight, possibility to join different materials and, currently, existence of reliable numerical methods to predict the strength of adhesive joints, the which reduces the costs associated with overdesign, previously an issue due to the lack of information about the adhesive bonds. The T-peel peel test is widely used because it is easy to reproduce, low cost and can be performed in universal testing machines. The floating roller peel test is used in the industry to assess the adhesion quality in adhesive joints, as it subjects the adhesive joint to extreme conditions of application. The present work aims to characterize the peel strength of the structural adhesive Araldite® AV138 applied to adhesive joints manufactured with adherends of different natures through numerical modelling of the floating roller peel test. Adhesive joints made of carbon fibre reinforced polymer (CFRP) and aluminium alloy (AW 6082-T651) were used. The numerical model was based on cohesive zone models (CZM) applied in the ABAQUS® software. To reliably model the contact between the adherends and the fixing rollers, the rollers were included in the tests and the respective contact conditions and connections established. To validate and confirm the reliability of the results obtained through the numerical floating roller peel test, the predictions obtained were compared with previously established experimental results. The results indicated that the used numerical technique reproduced the physical behaviour of the tests and enabled to accurately predict the peel strength of the structural adhesive Araldite® AV138.
Currently, adhesive joints are widely used in the design of mechanical structures, to the detriment of classical mechanical joints, namely bolted or riveted. The choice of adhesive joints in design is due to the more uniform distribution of stresses and reduction of structural weight, possibility to join different materials and, currently, existence of reliable numerical methods to predict the strength of adhesive joints, the which reduces the costs associated with overdesign, previously an issue due to the lack of information about the adhesive bonds. The T-peel peel test is widely used because it is easy to reproduce, low cost and can be performed in universal testing machines. The floating roller peel test is used in the industry to assess the adhesion quality in adhesive joints, as it subjects the adhesive joint to extreme conditions of application. The present work aims to characterize the peel strength of the structural adhesive Araldite® AV138 applied to adhesive joints manufactured with adherends of different natures through numerical modelling of the floating roller peel test. Adhesive joints made of carbon fibre reinforced polymer (CFRP) and aluminium alloy (AW 6082-T651) were used. The numerical model was based on cohesive zone models (CZM) applied in the ABAQUS® software. To reliably model the contact between the adherends and the fixing rollers, the rollers were included in the tests and the respective contact conditions and connections established. To validate and confirm the reliability of the results obtained through the numerical floating roller peel test, the predictions obtained were compared with previously established experimental results. The results indicated that the used numerical technique reproduced the physical behaviour of the tests and enabled to accurately predict the peel strength of the structural adhesive Araldite® AV138.
Description
Keywords
Adesivo Juntas adesivas Modo de rotura Previsão da resistência ao arrancamento Floating roller peel test Modelos de dano coesivo Adhesive Adhesive joints Failure mode Prediction of peel strength Floating roller peel test Cohesive zone models