A carregar...
Publicação
Structural improvements of a FishBAC design
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 3.58 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
A indústria aeronáutica é conhecida pela sua elevada exigência. Actualmente, essa exigência é cada vez mais notória, o que leva à procura ativa de ideias e soluções que sejam inovadoras, criativas e mais eficientes para a continua evolução do desempenho das aeronaves. Uma das novas e promissoras ideias é a asa do tipo Fish Bone Active Camber (FishBAC), que se insere na categoria de asas que tem uma curvatura variável consoante o pretendido. Neste trabalho, propõe-se novas soluções que possam responder às limitações dos modelos atuais da tecnologia FishBAC.
Como mecanismo adaptativo (morphing) baseado na flexibilidade, a distribuição e orientação da rigidez dentro do FishBAC são incrivelmente importantes. O objectivo geral é conseguir uma elevada flexibilidade na direcção da curvatura variável mantendo, simultaneamente, uma elevada rigidez nas outras direcções. A geometria do FishBAC foi projetada para criar um elevado nível de anisotropia estrutural. Este trabalho procura levar esta estrutura mais longe, investigando uma série de alterações de concepção que irão aumentar ainda mais a anisotropia geométrica e dos materiais utilizados, de modo a aumentar o desempenho do FishBAC .
Estas soluções foram obtidas usando três modelos diferentes. O primeiro modelo apresenta recortes rectangulares na espinha (spine). O segundo tem pultrusões de polímero reforçádo com fibra de carbono (Carbon fiber reinforced polymer - CFRP) presasãs longarinas e colocadas junto à pele (skin). E o terceiro modelo combina as características dos outros dois. Os resultados de uma análise de elementos finitos (Finite Element Analysis - FEA), obtidos para estes modelos, foram comparados a um modelo
básico FishBAC sem modificações. Concluiu-se que os recortes têm um efeito positivo na diminuição da rigidez do modelo, com um impacto modesto na variação da deflexão do bordo de fuga, ao longo da envergadura. As pultrusões de CFRP demonstraram ser muito menos eficazes para responder ao problema da elevada variação da deflexão do bordo de fuga do que seria de esperar para estruturas quem incluem este tipo de reforços (pultrusões de CFRP).
The aeronautical industry is well known for its high demands. Nowadays, the demands are higher and more visible, which leads to the active search of new ideas and solutions that are innovative, creative and more efficient for the continuous evolution of the aircraft’s performance. One of these new and promising ideas is the Fish Bone Active Camber (FishBAC) wing, which is a type of camber morphing wing. This dissertation work proposes new solutions that aim to mitigate the limitations of the current models of the FishBAC technology. As a compliance-based morphing mechanism, the distribution and orientation of stiffness within the FishBAC are incredibly important. The overall goal is to achieve high compliance in the camber morphing direction while maintaining high stiffness in the other directions. The geometry of the FishBAC is designed to create a high level of structural anisotropy. This work seeks to push this structure further by investigating a series of design changes which will further augment the material and geometric anisotropy in order to increase the performance of the FishBAC. These solutions were obtained using three different models. The first model presents a spine with rectangular cutouts. The second one has Carbon Fibre Reinforced Polymer (CFRP) pultrusions attached to the stringers next to the skin. The third model combines the characteristics of the other two. The results obtained through the Finite Element Analysis (FEA) for these models, were compared to a basic FishBAC model with no modifications. This process helped to conclude, that cutouts have a positive effect in diminishing the stiffness of the model with a modest impact in deflection variation along the wingspan. The CFRP pultrusions have shown to be much less effective to respond to this deflection variation problem than it was expected.
The aeronautical industry is well known for its high demands. Nowadays, the demands are higher and more visible, which leads to the active search of new ideas and solutions that are innovative, creative and more efficient for the continuous evolution of the aircraft’s performance. One of these new and promising ideas is the Fish Bone Active Camber (FishBAC) wing, which is a type of camber morphing wing. This dissertation work proposes new solutions that aim to mitigate the limitations of the current models of the FishBAC technology. As a compliance-based morphing mechanism, the distribution and orientation of stiffness within the FishBAC are incredibly important. The overall goal is to achieve high compliance in the camber morphing direction while maintaining high stiffness in the other directions. The geometry of the FishBAC is designed to create a high level of structural anisotropy. This work seeks to push this structure further by investigating a series of design changes which will further augment the material and geometric anisotropy in order to increase the performance of the FishBAC. These solutions were obtained using three different models. The first model presents a spine with rectangular cutouts. The second one has Carbon Fibre Reinforced Polymer (CFRP) pultrusions attached to the stringers next to the skin. The third model combines the characteristics of the other two. The results obtained through the Finite Element Analysis (FEA) for these models, were compared to a basic FishBAC model with no modifications. This process helped to conclude, that cutouts have a positive effect in diminishing the stiffness of the model with a modest impact in deflection variation along the wingspan. The CFRP pultrusions have shown to be much less effective to respond to this deflection variation problem than it was expected.
Descrição
Autor: Tiago Emanuel Pereira Nunes; ALFAL/ENGAER 139923-D
Thesis to obtain the Master of Science Degree in Military and Aeronautical Sciences - Aeronautical Engineering
Examination Committee:
Chairperson: BGEN/ENGAER 086084-A João Rui Ramos Nogueira
Supervisor: Prof. Benjamin King Sutton Woods
Co-Supervisor: TCOR/ENGAER 129905-A Luís Filipe da Silva Félix
Member of the Committee: Prof. Frederico José Prata Rente Reis Afonso
Palavras-chave
Análise de elementos finitos Modelo computacional Asa adaptativa FishBAC Fibra de carbono reforçada com polímero FEA CAD Morphing wing CFRP
Contexto Educativo
Citação
Nunes, T. E. O. (2022). Structural improvements of a FishBAC design. (Master’s Dissertation in Military and Aeronautical Sciences, Aeronautical Engineering). Air Force Academy [AFA], Sintra.
Editora
Academia da Força Aérea