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Authors
Abstract(s)
A necessidade de utilizar métodos de ligação que melhor satisfaçam as necessidades de
projeto tem causado a crescente utilização das juntas adesivas, em detrimento dos métodos
tradicionais tais como a soldadura, ligações aparafusadas e rebitadas. A sua utilização em
diversas aplicações industriais justifica-se pela redução de peso, redução de concentrações
de tensões, isolamento acústico e melhor resistência à corrosão. Contudo, também
apresentam desvantagens, como a necessidade de preparação das juntas, a fraca resistência
a esforços de arrancamento e a complexidade da previsão da sua resistência. As juntas
híbridas são obtidas por combinação de uma técnica tradicional com uma ligação adesiva.
As juntas híbridas adesivas-soldadas obtêm-se através da combinação da ligação adesiva
com a ligação soldada, sendo a soldadura de resistência por pontos a técnica de soldadura
mais usada no fabrico deste tipo de juntas. A sinergia entre ligação adesiva e soldadura por
pontos oferece vantagens competitivas em relação às ligações adesivas, tais como superior
resistência e rigidez, e maior resistência ao arrancamento e à fadiga.
No presente trabalho é apresentado um estudo experimental e numérico de juntas T-peel
soldadas, adesivas e híbridas (adesivas-soldadas) solicitadas ao arrancamento. Considerouse
o adesivo frágil Araldite® AV138 e os adesivos dúcteis Araldite® 2015 e Sikaforce® 7752
e aderentes de aço (C45E). Foi realizada uma análise dos valores experimentais e efetuada
uma comparação destes valores com os resultados obtidos pelo Método de Elementos Finitos
(MEF) no software ABAQUS®, que incluiu uma análise de tensões na camada de adesivo e
previsão do comportamento das juntas por MDC. Observou-se que, dos três adesivos em
estudo, o adesivo Sikaforce® 7752 é o que apresenta o melhor desempenho na ligação de
juntas T-peel. A boa concordância entre os resultados experimentais e numéricos permitiu
validar a utilização de MDC para previsão da resistência de juntas T-peel adesivas e híbridas.
Assim, o presente trabalho representa uma base para posterior aplicação no projeto deste
tipo de ligação, com as vantagens decorrentes na redução do tempo de projeto e maior
facilidade de otimização.
The need of joining methods that best meet the design requirements has led to the increased use of adhesive joints at the expense of the traditional methods such as welding, fastening and riveting. Their use in various industrial applications is justified by the weight reduction, reduction of stress concentrations, acoustic insulation and improved corrosion resistance. However, they also present disadvantages, such as the need of joint preparation, the poor resistance to peel loads and the complexity in the strength prediction. Hybrid joints are obtained by combining a traditional technique with adhesive bonding. Hybrid weld-bonded joints are obtained by combining adhesive bonding with a welded joint, being spot-welding the most widely used welding technique in the manufacture of such joints. The synergy between adhesive bonding and spot-welding provides competitive advantages over adhesive bonding, such as superior strength and stiffness, and higher resistance to peeling and fatigue. In the present work, an experimental and numerical study of T-peel welded, adhesive and hybrid (adhesive-welded) joints is presented under peeling loads. The brittle adhesive Araldite® AV138 and the ductile adhesives Araldite® 2015 and Sikaforce® 7752 were considered between steel substrates (C45E). An analysis of the experimental values and a comparison of these values with Finite Element Method (FEM) results in the ABAQUS® software was carried out, which included a stress analysis in the adhesive layer and joint strength prediction by Cohesive Zone Models (CZM). It was found that, between the three adhesives studied, the Sikaforce® 7752 adhesive is the one with the best performance in bonding T-peel joints. The good agreement between the experimental and numerical results enabled the validation of CZM to predict the strength of adhesive and hybrid T-peel joints. The present work is a basis for further application in the design of this type of joints, with the benefits in reducing the design time and ease of optimization.
The need of joining methods that best meet the design requirements has led to the increased use of adhesive joints at the expense of the traditional methods such as welding, fastening and riveting. Their use in various industrial applications is justified by the weight reduction, reduction of stress concentrations, acoustic insulation and improved corrosion resistance. However, they also present disadvantages, such as the need of joint preparation, the poor resistance to peel loads and the complexity in the strength prediction. Hybrid joints are obtained by combining a traditional technique with adhesive bonding. Hybrid weld-bonded joints are obtained by combining adhesive bonding with a welded joint, being spot-welding the most widely used welding technique in the manufacture of such joints. The synergy between adhesive bonding and spot-welding provides competitive advantages over adhesive bonding, such as superior strength and stiffness, and higher resistance to peeling and fatigue. In the present work, an experimental and numerical study of T-peel welded, adhesive and hybrid (adhesive-welded) joints is presented under peeling loads. The brittle adhesive Araldite® AV138 and the ductile adhesives Araldite® 2015 and Sikaforce® 7752 were considered between steel substrates (C45E). An analysis of the experimental values and a comparison of these values with Finite Element Method (FEM) results in the ABAQUS® software was carried out, which included a stress analysis in the adhesive layer and joint strength prediction by Cohesive Zone Models (CZM). It was found that, between the three adhesives studied, the Sikaforce® 7752 adhesive is the one with the best performance in bonding T-peel joints. The good agreement between the experimental and numerical results enabled the validation of CZM to predict the strength of adhesive and hybrid T-peel joints. The present work is a basis for further application in the design of this type of joints, with the benefits in reducing the design time and ease of optimization.
Description
Keywords
Junta em T Junta híbrida Adesivo Elementos Finitos Modelos de Dano Coesivo T-peel joint Hybrid joint Adhesive Finite Elements Cohesive Zone Models