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Authors
Abstract(s)
A prática de ligações adesivas, ou coladas, tem sido utilizada em diversas áreas como a
indústria automóvel, aeronáutica, naval, componentes de electrónica, civil, madeiras,
entre outras, com uma grande relevância. A sua utilização tem surgido em detrimento
de outros métodos de ligação tradicionais tais como ligações aparafusadas, rebitadas e
soldadas. A expansão da sua utilização a todas as indústrias deve-se essencialmente à
facilidade de fabricação, menores custos, facilidade de união entre materiais distintos,
melhor resistência à fadiga e distribuição uniforme das tensões. A ligação por chanfro
interno é uma das configurações possíveis e viáveis para aplicação pois não exige que
se altere a forma inicial do componente. Apresenta ainda vantagens relativamente à
distribuição mais uniforme de tensões quando comparada com juntas de sobreposição
simples ou dupla, embora haja alguma complexidade na execução.
Neste trabalho pretendeu-se fazer o estudo da ligação com chanfro utilizando dois
substratos de materiais distintos aplicando diversos ângulos de chanfro. O estudo
experimental consistiu no ensaio de tração, permitindo obter as curvas de forçadeslocamento
(P-). A análise numérica por Elementos Finitos permitiu realizar um
estudo de tensões de arrancamento (σy) e de corte (τxy), utilizando o software
ABAQUS®. A utilização de Modelos de Dano Coesivo foi realizada para previsão
numérica da resistência das juntas. Constatou-se uma variação significativa do
comportamento das juntas consoante o ângulo de chanfro aplicado e adesivo. Como
conclusão, considera-se os modelos numéricos adequados para serem usados como
ferramenta de validação, embora a lei coesiva a utilizar deva de ser revista e
melhorada para os adesivos dúcteis.
The practice of adhesive or glued joints has been used in many areas such as automotive and aeronautic industries, navy, electronic components, construction, woods and others, with a big relevance. Their use has emerged to the detriment of other traditional joint methods such as bolted, riveted and welded joints. The expansion of their use in all those industries is essential due to an easy manufacturing, lower costs, easiness to joint different materials, better failure resistance and uniform distribution of stresses. The scarf joint is one of the possible and a viable configurations for application because does not require to change the initial shape of the component. This joint presents other advantages, namely an uniform distribution of the stresses when compared with single and double overlap joints, although it has some complexity in the manufacturing process. The main goal of this work is make a study about scarf joints using two adherents with different materials and varying the scarf angles. The experimental study consists of performing tensile tests and obtaining the load-displacement (P-) curves. The numerical analysis by Finite Elements was performed to obtain peel (σy) and shear (τxy) stresses, using the software ABAQUS®. Cohesive Zone Models (CZM) were used to predict the joint strength. In the end, a significant variation was confirmed on the behavior of the joints depending on the chamfer angle used and the adhesive applied. As a conclusion, numerical models are considered suitable to use as a validation tool, although the cohesive law should be revised and improved for ductile adhesives.
The practice of adhesive or glued joints has been used in many areas such as automotive and aeronautic industries, navy, electronic components, construction, woods and others, with a big relevance. Their use has emerged to the detriment of other traditional joint methods such as bolted, riveted and welded joints. The expansion of their use in all those industries is essential due to an easy manufacturing, lower costs, easiness to joint different materials, better failure resistance and uniform distribution of stresses. The scarf joint is one of the possible and a viable configurations for application because does not require to change the initial shape of the component. This joint presents other advantages, namely an uniform distribution of the stresses when compared with single and double overlap joints, although it has some complexity in the manufacturing process. The main goal of this work is make a study about scarf joints using two adherents with different materials and varying the scarf angles. The experimental study consists of performing tensile tests and obtaining the load-displacement (P-) curves. The numerical analysis by Finite Elements was performed to obtain peel (σy) and shear (τxy) stresses, using the software ABAQUS®. Cohesive Zone Models (CZM) were used to predict the joint strength. In the end, a significant variation was confirmed on the behavior of the joints depending on the chamfer angle used and the adhesive applied. As a conclusion, numerical models are considered suitable to use as a validation tool, although the cohesive law should be revised and improved for ductile adhesives.
Description
Keywords
Adesivo Juntas com Chanfro Interno Juntas Híbridas Métodos de Elementos Finitos Modelos de Dano Coesivo Adhesive Scarf Joints Hybrid Joints Finite Element Method Cohesive Zone Models