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The introduction of creases into thin sheets has a dramatic effect on their global mechanical properties. This can be observed by manipulating a crumpled piece of paper which has been unfolded; it no longer deforms in the same way as the original sheet. Creases have typically been modelled as singular hinge lines, often accompanied by a torsional spring to provide some opening resistance; however, the appropriate stiffness of these springs is unclear. In reality, creases have a discrete geometry based on the method they were formed. This dissertation investigates the flexural behaviour of a creased thin metallic strip and the influence of the crease geometry. When a strip is bent perpendicular to the crease, putting the crease region in tension and the strip edges in compression, initially torsional deformations occur which ultimately coalesce into a central localised flattened region. An analytical model of this flexural behaviour is developed, which idealises the crease as an initially circular segment. Predictions show the bending resistance increases as the crease decreases in size. The model predictions are compared to finite element analysis and experimental results showing excellent agreement. When a strip is bent in the opposite direction, with the crease region in compression and the strip edges in tension, a bistable snap-through occurs. The deformed shape is characterised by a sharp vertex on the crease line. An analytical model is developed by generalising a Gauss mapping approach, and used to predict the deformed shape. These predictions match experimental results well. This dissertation provides an understanding of the mechanics of creased thin strips, where the crease is given a discrete geometry, and explores the nature of localisation. It also provides the foundation to explore the mechanics of thin sheets featuring a network of creases. This offers the opportunity to improve the efficiency of thin shell structures by using creasing to optimise the mechanics, leading to reduced material use, more sustainable construction, and fuel savings from lighter vehicles.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-08-25T17:48:43Z No. of bitstreams: 1 texto completo.pdf: 1910190 bytes, checksum: 89986d80c7413c6470f9b16bd4ebbab6 (MD5) / Made available in DSpace on 2016-08-25T17:48:43Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1910190 bytes, checksum: 89986d80c7413c6470f9b16bd4ebbab6 (MD5) Previous issue date: 2015-04-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta dissertação elaboramos uma proposta de atividade educacional que envolve o ensino da Geometria Plana através de recursos manipuláveis. O trabalho consta de revisão bibliográfica, apresentando a proposta de ensino do PCN e CBC em relação à Geometria, um breve histórico do Origami, do Tangram e do Geoplano e as habilidades desenvolvidas por esses instrumentos, dando subsídios para elaboração de atividades em sala. Neste contexto, apresentamos atividades que podem ser utilizadas como estímulo ao envolvimento com a geometria. Concluímos citando alguns outros recursos didáticos que podem ser utilizados pelos professores e alunos. / In this dissertation developed a proposal for educational activity that involves the teaching of plane geometry through manipulatives resources. The work consists of bibliographic review, presenting the proposal for teaching the PCN and CBC in relation to geometry, a brief history of Origami, Tangram and Geoplano and skills developed by these instruments, providing subsidies for preparation room activities. In this context, present activities that can be used as a stimulus to the involvement with the geometry. We conclude by quoting other teaching resources that can be used by teachers and students.

MENEZES, Daniel Brandão. O Uso de dobraduras como recurso para o ensino da geometria plana : histórias, teoremas e problemas. 2014. 64 f. Dissertação (Mestrado em Matemática em Rede Nacional) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2014. / Submitted by Erivan Almeida (eneiro@bol.com.br) on 2014-05-14T17:30:46Z No. of bitstreams: 1 2014_dis_dbmenezes.pdf: 2044522 bytes, checksum: 55801ae891fdd7fdd8ee00768338c2e6 (MD5) / Approved for entry into archive by Rocilda Sales(rocilda@ufc.br) on 2014-05-15T13:44:52Z (GMT) No. of bitstreams: 1 2014_dis_dbmenezes.pdf: 2044522 bytes, checksum: 55801ae891fdd7fdd8ee00768338c2e6 (MD5) / Made available in DSpace on 2014-05-15T13:44:52Z (GMT). No. of bitstreams: 1 2014_dis_dbmenezes.pdf: 2044522 bytes, checksum: 55801ae891fdd7fdd8ee00768338c2e6 (MD5) Previous issue date: 2014 / A constant concern in the school teacher’s performance by the new reality of the Brazilian mathematics education motivated the beginning of this study, since learning undergoes constant modifications and holders of knowledge need to monitor the changes in such a scenario. Thus, the aim of this work is to enable a literary source for the school teachers and deepen their theoretical basis to transmit the contents of Euclidean Plane Geometry with the use of concrete materials in their classrooms. The methodology used was the literature survey of articles that focus on the main theme of the necessary geometry taught by folds learning outcomes as well as, studies and articles in scientific studies trying to adapt mathematical concepts to the playful work with the folding of paper. As major result, we can mention the creation of a text about history of folding, theorems and problems involving geometry and different ways to solve them through a playful and also theoretically. Numerous models of future work can be discussed: the use of Geogebra software for the application of the folds, controlled application of resolutions proposed in the classroom jointly with getting the results before the students, recording vídeos and performing the folds create a textbook for students based on conclusions drawn from this work. / A constante preocupação no desempenho do professor do ensino básico mediante a nova realidade da educação matemática brasileira motivou o início deste estudo, uma vez que a aprendizagem sofre constantes modificações e os detentores do conhecimento necessitam acompanhar as mudanças ocorridas em tal cenário. Diante disso, o objetivo deste trabalho é possibilitar uma fonte literária para o professor do ensino básico e aprofundar seu embasamento teórico para transmitir o conteúdo de Geometria Euclidiana Plana com o uso de materiais concretos em suas salas de aula. A metodologia utilizada foi o levantamento bibliográfico de obras que focam os principais resultados necessários ao aprendizado do tema de geometria ensinado por meio de dobras, bem como, os estudos realizados em artigos e trabalhos científicos buscando adaptar os conceitos matemáticos ao trabalho lúdico com as dobraduras de papel. Como resultado principal, pode-se citar a criação de um texto sobre a história das dobras, Teoremas e problemas que envolvem a geometria e o modo diverso de resolvê-los, por meio de uma forma lúdica e também teórica. Inúmeros modelos de trabalhos futuros podem ser discutidos como: utilização do software Geogebra para a aplicação das dobras, aplicação controlada das resoluções propostas em sala de aula juntamente com a obtenção dos resultados perante os alunos, gravação de vídeos da realização das dobras e criação de um livro texto para os alunos baseado nas conclusões retiradas desta obra.

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Esta dissertação apresenta questões relativas às pessoas surdas, predominantemente no âmbito da Educação, mais particularmente no Ensino da Matemática. Parte-se de análise do perfil dos surdos enquanto indivíduos e como grupo social, logo após centrando-se no histórico de sua educação – formal, inclusive - até contextos e tendências na atualidade. Vygotsky e Sacks ganham destaque enquanto fundamentação teórica. São feitos relatos de experiências com surdos, dentro e fora da Escola. Além disso, são descritos e avaliados atividades e resultados de um estudo de caso que utilizou o Origami como recurso nas aulas de Geometria, em duas escolas da Educação Especial. Como resultado da experiência acumulada da autora como intérprete e professora de surdos há alguns anos, da pesquisa realizada e da experimentação prática, este trabalho visa estimular professores à reflexão sobre o ensino para surdos, em particular o de Matemática, com ênfase na barreira de comunicação existente entre os pares e no modo pelo qual se mostra promissora a exploração do Origami com os surdos – duas das conclusões deste trabalho.

Minimally invasive surgery improves patient recovery time, minimizes surgical complications, and leaves smaller incisions on the patient skin. Yet drawbacks prevent the complete adoption of these methods, including the lack of sensor feedback which can lead to unintended tissue damage during surgery. Soft robots have been developed to minimize damage compared to rigid counterparts, yet control techniques can become complicated and computationally taxing due to the flexibility of polymeric materials and hyper-redundancy in the system. Additionally, sensor integration in soft systems at a miniature scale and sensor feedback for closed-loop control remains challenging. Presented in this thesis is a millimeter-scale continuum robot created from monolithically fabricated, origami-inspired, fluidically actuated programmable composite actuator modules with embedded ionic resistive self-sensing. The modules consist of inflatable Teflon bellows surrounded by a rigid arm structure with flexible joints. Constraints in the rigid structure mechanically program different types of motion---translation, bending, and rototranslation. An ionic resistive sensing mode is embedded, using biocompatible working fluid at low voltage for position tracking. Modules are stacked in series to form a continuum robot and a model is developed and analyzed using sensor data to track tip position, with the reduced number of degrees of freedom in the system allowing for ease of modeling using robot joint kinematics. / 2025-05-24T00:00:00Z

This report explores the use of origami techniques in the space, medical and military fields. This new design method will modify the design process and reduce costs. The origami design method will also improve the device’s performance and quality of the device. The most important and complex procedures are the selection and the fabrication processes for designing the origami devices. New software is necessary for origami design. The military, medical, and space sectors are leading this research and development. As the concept is new, very few devices have been made with success. This paper outlines the development of origami design and describes the applications as well as the material selection and fabrication process.

L' objet d'étude de cette thèse est l' origami d' ADN. Le nombre important d'applications utilisant cette technique, et leurs diversités, sont des preuves que ces structures présentées en 2007 sont une avancée importante pour la technologie ADN. Dans cette thèse nous présentons dans un premier temps les résultats de simulations sur les propriétés mécaniques de ces nouvelles structures. Les résultats d'expériences et de simulations sur le processus de formations pour de petites structures d'ADN et sur des origamis d'ADN sont présentés dans une deuxième partie. Finalement une application de ces structures à la détection SERS est proposée, et les résultats expérimentaux concernant la réalisation de cette structure sont discutés. / DNA origami are new nanostructures (2006) whose physical properties are still to be understood. In this work we were first interested in their mechanical properties. The first approach of this study was through the use of polymer physics, as it is the classical way to study DNA. We then used computer simulations to model the system in a more detailed manner and to extract general rules on the mechanical behaviour of DNA constructs. The other aspect that we studied is the process of formation of DNA origamis. We first realised an experimental study of the process of formation of the simplest origami that we could envision. This study was intended to investigate basic principles on the process of formation of DNA structures. A coarse grain model is then developed to have a first insight onto the formation process. Then an experimental study on large origamis follows with a modeling of the annealing and melting curves based on the principles determined from the study of the simplest origami. We also worked on the development of a SERS platform.

O presente trabalho contém sugestões de práticas de ensino, utilizando o origami modular, que podem ser aplicadas nas aulas de geometria do Ensino Fundamental. As práticas foram desenvolvidas de maneira que o professor possa enriquecer suas aulas gastando pouco tempo no preparo, e apresentam objetos manipuláveis que tornam o processo de ensino-aprendizagem mais atrativo e significativo. Apresentamos todo o processo de elaboração dos módulos e seus respectivos encaixes para a construção, usando origami modular, dos cinco Poliedros de Platão utilizados nas propostas de práticas de ensino. / This study suggests the origami modular as a teaching method to be used in Geometry class of Elementary School. The origami modular technique was developed for educators to advance their teaching approaches with hands-on activities without spending too much time to prepare for class, producing a more interactive and attractive learning-teaching process. In this study, we will describe the entire procedure to create and to build the modules with its corresponding parts using the origami modular originated from the five Platonic solids proposed in teaching methods.