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Abstract(s)
A canoagem é uma modalidade náutica que surgiu na história há milhares de anos
simplesmente como um meio de sobrevivência. Nos dias de hoje, esta modalidade é
praticada em todo o mundo, como meio de lazer ou competição. Face à vontade de
melhorar a qualidade de construção e desempenho das embarcações, atualmente o seu
fabrico permanece centrado na utilização de materiais compósitos. Apesar de existirem
inúmeras formas de unir os diferentes componentes que existem, a que mais se destaca
é a ligação adesiva. Por outro lado, para uma empresa de fabrico destas embarcações
se manter competitiva no mercado, é necessária a melhoria contínua destas ligações em
termos de resistência e custo de fabrico.
Nesta dissertação é estudada numericamente uma ligação adesiva existente numa
embarcação de canoagem, mais concretamente, a união entre o casco e o deck de um
kayak. Para avaliar o desempenho desta junta adesiva é necessário conhecer os tipos de
materiais implícitos neste tipo de junta, assim como os principais parâmetros
geométricos. Inicialmente, o adesivo utilizado foi testado à tração com provetes de
adesivo maciço e os respetivos dados tratados, para obter os parâmetros materiais
necessários à análise. Para concretizar o objetivo da dissertação, é efetuada uma análise
numérica, na qual é testado o método atual de união existente, e ainda analisadas
diferentes alterações geométricas e considerados diferentes tipos de adesivos que
possam trazer a esta ligação adesiva melhores propriedades. O trabalho numérico
consistiu numa análise elástica de tensões da camada de adesivo e previsão de rigidez e
resistência, por modelos de dano coesivo (MDC), utilizando-se o software ABAQUS®.
Para utilização do MDC para estudo das diferentes configurações de junta, antes foi
realizada uma validação da técnica com dados experimentais obtidos em trabalhos
anteriores.
Este estudo numérico permitiu inicialmente validar com sucesso os MDC e, de seguida,
analisar numericamente a influência das alterações geométricas consoante os
diferentes tipos de adesivos, possibilitando a verificação de qual geometria se adapta
melhor a cada tipo de adesivo considerado
Canoeing is a nautical sport that appeared in history thousands of years ago simply as a means of survival. Nowadays, this sport is practiced all over the world as a hobby or as a means of competition. Given the desire to improve the quality of construction and performance of boats, currently their manufacture is focused on the use of composite materials. Although there are countless ways to join the different components that exist, the one that stands out the most is adhesive bonding. On the other hand, for a manufacturing company of these boats to remain competitive in the market, it is required the continuous improvement of these joints in terms of strength and manufacturing cost. In this dissertation, an adhesive joint existing in a canoeing boat is numerically studied, more specifically the joint between the hull and the deck of a kayak. To evaluate the performance of this adhesive joint, it is necessary to know the types of materials implicit in this type of joint, as well as the main geometric parameters. Initially, the adhesive used was tensile tested with bulk adhesive specimens and the respective data was processed to obtain the material parameters required for the analysis. To achieve the goal of this dissertation, a numerical analysis is performed, in which the existing joint configuration was tested, different geometric changes were analyzed and different types of adhesives that can bring improved properties to this adhesive bond were considered. The numerical work consisted of an elastic stress analysis of the adhesive layer and prediction of stiffness and strength, by cohesive zone modelling (CZM), using the ABAQUS® software. To use the CZM to study the different joint configurations, a prior validation of the technique was performed with experimental data obtained in a previous work. Initially, this numerical study enabled to successfully validate the CZM and, then, to numerically evaluate the influence of geometric changes according to different adhesive types, allowing the verification of which geometry best adapts to each adhesive type that was considered
Canoeing is a nautical sport that appeared in history thousands of years ago simply as a means of survival. Nowadays, this sport is practiced all over the world as a hobby or as a means of competition. Given the desire to improve the quality of construction and performance of boats, currently their manufacture is focused on the use of composite materials. Although there are countless ways to join the different components that exist, the one that stands out the most is adhesive bonding. On the other hand, for a manufacturing company of these boats to remain competitive in the market, it is required the continuous improvement of these joints in terms of strength and manufacturing cost. In this dissertation, an adhesive joint existing in a canoeing boat is numerically studied, more specifically the joint between the hull and the deck of a kayak. To evaluate the performance of this adhesive joint, it is necessary to know the types of materials implicit in this type of joint, as well as the main geometric parameters. Initially, the adhesive used was tensile tested with bulk adhesive specimens and the respective data was processed to obtain the material parameters required for the analysis. To achieve the goal of this dissertation, a numerical analysis is performed, in which the existing joint configuration was tested, different geometric changes were analyzed and different types of adhesives that can bring improved properties to this adhesive bond were considered. The numerical work consisted of an elastic stress analysis of the adhesive layer and prediction of stiffness and strength, by cohesive zone modelling (CZM), using the ABAQUS® software. To use the CZM to study the different joint configurations, a prior validation of the technique was performed with experimental data obtained in a previous work. Initially, this numerical study enabled to successfully validate the CZM and, then, to numerically evaluate the influence of geometric changes according to different adhesive types, allowing the verification of which geometry best adapts to each adhesive type that was considered
Description
Keywords
Canoagem Juntas adesivas Adesivo estrutura Compósitos Modelação numérica Método de elementos finitos Modelos de dano coesivo Canoeing Adhesive joints Structural adhesive Composites Numerical modeling Finite element method Cohesive zone model