Lightweight skins for UAV wings

• Autor(a) principal: Correia, Rodrigo Barata
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/13770
• topic: Cascas Leves; Fea; Fibra de Carbono; Flexão em Três Pontos; Rigidez à Flexão; Sanduíche em Compósito; Uav; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica

This work investigates different production methods and the mechanical and elastic behavior of composite sandwich structures under bending stress. Fiber cloth materials like carbon fiber and core materials like Airex foam, balsa wood, and honeycomb structures are analyzed in different layups both experimentally and computationally. The main objective of this study is to identify which composite sandwich has better mechanical properties and can be used as a lightweight structure for the wing skin of small airplanes like UAVs. For that, a three-point bending test was performed and followed by a structural analysis simulation in ANSYS® to validate the results obtained. The samples tested have a relatively low thickness in order to be suitable for small UAVs (less than 2.5 mm). All of the samples were produced with two layers of a lightweight 30 g/m2 carbon fiber cloth on each side of the sandwich and a core material. The balsa wood sandwich was the most weight-efficient sample with a strength per unit of mass of 11.49 N/g and also the most rigid with a flexural modulus of 3.18 GP a. The AIREX® C 70.75 foam sandwich was the least weight efficient sample with a strength per unit of mass of 5.91 N/g and also the least rigid with a flexural modulus of 0.86 GP a. The Nomex® honeycomb core sandwich oriented in the lengthwise and widthwise direction had a strength per unit of mass of 9.62 N/g and 9.11 N/g and a flexural modulus of 1.00 GP a and 1.08 GP a respectively. Even though the finite element analysis results were not satisfactory, the experimental procedures and experiments were successfully performed and enough data was collected in order to take reliable conclusions concerning the use of the most adequate lightweight sandwich structure for UAV wings with the balsa wood sandwich being the one with the better overall performance.