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Abstract(s)
Apesar de serem utilizados desde a antiguidade, os adesivos tendem a ser cada vez mais utilizados na indústria moderna. A introdução de adesivos baseados em polímeros sintéticos trouxe diversas vantagens quando comparados com os métodos tradicionais de ligação. As vantagens das ligações adesivas incluem redução de peso, capacidade de vedação, união de materiais diferentes sem danificação dos materiais de base e melhor distribuição de tensões. Com o crescimento do uso de juntas adesivas estruturais, especialmente na indústria aeronáutica, surge a necessidade de ferramentas de simulação mais precisas, como o método de elementos finitos (MEF) que, combinados com modelos de dano coesivo (MDC), permitem
projetar e prever o desempenho destas ligações. As juntas adesivas são amplamente utilizadas em indústrias como a aeroespacial, aeronáutica, automóvel, construção civil e eletrónica. Esta dissertação tem como objetivo avaliar experimental e numericamente a resistência à tração de juntas adesivas tubulares, utilizando os adesivos Araldite® AV138 e Araldite® 2015. O estudo analisa a influência de parâmetros geométricos, como o comprimento de sobreposição (Lo), a espessura dos aderentes (ts) e o diâmetro exterior do aderente interior (dsi), no comportamento mecânico das juntas. No âmbito do trabalho experimental, são fabricados os
provetes e realizados ensaios experimentais, com os dados analisados posteriormente. No trabalho numérico, são criados modelos no software ABAQUS®, utilizando um MDC triangular para simular o comportamento das juntas até à rotura. Após a validação com os dados experimentais, o estudo paramétrico numérico realizado pretende avaliar a influência dos parâmetros geométricos na distribuição de tensões e na capacidade de carga das juntas. Com esta análise, o trabalho visa otimizar o desempenho estrutural das juntas adesivas em
diferentes configurações geométricas. O MDC testado foi validado com sucesso após comparação com os dados experimentais. O estudo paramétrico revelou que o adesivo Araldite® 2015 apresentou, de uma maneira geral, melhor desempenho em termos de resistência e dissipação de energia. O aumento de Lo e dsi
mostrou-se bastante benéfico para o desempenho das juntas, enquanto a variação de ts registou apenas alterações ligeiras no comportamento das mesmas.
Although they have been used since ancient times, adhesives tend to be used more and more in modern industry. The introduction of adhesives based on synthetic polymers has brought several advantages when compared to traditional joining methods. The advantages of adhesive joints include weight reduction, sealing capacity, joining different materials without damaging the base materials, and better stress distribution. With the growth in the use of structural adhesive joints, especially in the aeronautical industry, there is a need for more accurate simulation tools, such as the finite element method (FEM) which, combined with cohesive zone models (CZM), make it possible to design and predict the performance of these joints. Adhesive joints are widely used in industries such as aerospace, aeronautics, automotive, construction, and electronics. This dissertation aims to experimentally and numerically evaluate the tensile strength of tubular adhesive joints using the adhesives Araldite® AV138 and Araldite® 2015. The study analyses the influence of geometric parameters such as the overlap length (Lo), the thickness of the adherends (ts), and the outer diameter of the inner adherend (dsi) on the mechanical behaviour of the joints. As part of the experimental work, the specimens are manufactured and experimental tests are carried out, with the data analysed later. In the numerical work, models are created in the ABAQUS® software, using a triangular CZM to simulate the behaviour of the joints until failure. After validation with experimental data, the numerical parametric study aims to evaluate the influence of geometric parameters on the stress distributions and load capacity of the joints. With this analysis, the work aims to optimize the structural performance of adhesive joints in different geometric configurations. The tested CZM was successfully validated after comparison with experimental data. The parametric study revealed that the adhesive Araldite® 2015 generally performed better in terms of strength and energy dissipation. Increasing Lo and dsi proved to be very beneficial for the performance of the joints, while varying ts showed only slight changes in their behaviour.
Although they have been used since ancient times, adhesives tend to be used more and more in modern industry. The introduction of adhesives based on synthetic polymers has brought several advantages when compared to traditional joining methods. The advantages of adhesive joints include weight reduction, sealing capacity, joining different materials without damaging the base materials, and better stress distribution. With the growth in the use of structural adhesive joints, especially in the aeronautical industry, there is a need for more accurate simulation tools, such as the finite element method (FEM) which, combined with cohesive zone models (CZM), make it possible to design and predict the performance of these joints. Adhesive joints are widely used in industries such as aerospace, aeronautics, automotive, construction, and electronics. This dissertation aims to experimentally and numerically evaluate the tensile strength of tubular adhesive joints using the adhesives Araldite® AV138 and Araldite® 2015. The study analyses the influence of geometric parameters such as the overlap length (Lo), the thickness of the adherends (ts), and the outer diameter of the inner adherend (dsi) on the mechanical behaviour of the joints. As part of the experimental work, the specimens are manufactured and experimental tests are carried out, with the data analysed later. In the numerical work, models are created in the ABAQUS® software, using a triangular CZM to simulate the behaviour of the joints until failure. After validation with experimental data, the numerical parametric study aims to evaluate the influence of geometric parameters on the stress distributions and load capacity of the joints. With this analysis, the work aims to optimize the structural performance of adhesive joints in different geometric configurations. The tested CZM was successfully validated after comparison with experimental data. The parametric study revealed that the adhesive Araldite® 2015 generally performed better in terms of strength and energy dissipation. Increasing Lo and dsi proved to be very beneficial for the performance of the joints, while varying ts showed only slight changes in their behaviour.
Description
Keywords
Tubular adhesive joints Finite Element Method Cohesive Zone Models Geometric parameters Juntas adesivas tubulares Método de Elementos Finitos Modelos de Dano Coesivo Parâmetros geométricos