Additive Manufacturing of Resettable-Deformation Bi-Stable Lattices Based on a Compliant Mechanism

• Autor(a) principal: Calado, Ricardo Manuel Monteiro
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/153502
• topic: Mechanical Metamaterials; Bi-Stable Metamaterials; Additive Manufacturing; 3D Printing; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

Metamaterials allow for the possibility to design and fabricate new materials with enhanced me- chanical properties, through the use of additive manufacturing. There are some certain materials’ struc- tures that exhibit excellent properties to withstand externally applied forces. One example of this type of structure is a bi-stable switching mechanism which can regain its original position, after being sub- mitted to a compressive force. This kind of structure should be flexible and strong since it needs to undergo a certain deflection. Another important aspect that was addressed in this work is the structure’s geometry, because of the effect that it has on flexibility. Therefore, this thesis will focus on the proper study, design, 3D printing, and mechanical characterization of a novel unitary compliant bi-stable struc- ture, and its use to build two larger cellular compliant bi-stable structures, a four-cell and a multicell structure, using the unitary one as a building block. All structures were designed in the CAD software Fusion 360 and fabricated with Polylactic Acid filament using the Fused Filament Fabrication process. The fabricated structures were submitted to compressive tests, from where Force vs. Displacement plots were obtained. These results proved that the multicell structure was the stiffest, since it required higher compressive force to perform its function, when compared to the other two structures. The conducted tests were important to check the behavior of each structure while being compressed, where both struc- tures that had more than one cell showed a layered switching behavior. Also, the tests were important to check if the position recovery of the structures was possible to achieve, which was observed in all of them. After the compressive tests, all structures were also submitted to repetitive solicitation tests, to study their repeatability behavior. These results envisage the successful application of these mechanisms towards their implementation in microelectromechanical systems.