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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Kinematic analysis of foldable structures

Farrugia, Pierre January 2008 (has links)
The main objective of the present research is to develop a general method for the kinematic analysis of foldable structures. This objective is achieved in terms of a method called 'matrix dependency constraint' (MDC method) which is described in this thesis. The MDC method involves algebraic formulation of the geometry, degrees of freedom at the joints and the support conditions of a foldable structure.
2

Conceptual design and mechanisms for foldable pyramidal plated structures

Khayyat, Hassan A. January 2008 (has links)
In spite of the presence of much research in the field of foldable structures whose applications have covered most of the requirements of academic and practical aspects of life, there is still a wide domain in which to undertake further studies. One of the required studies is to invest in foldable structures for the process of temporary accommodation. This study endeavours to find solutions for folding pyramidal shapes constructed from stiff panels that can be used as an upper part of temporary accommodation units, e.g., roofs. Several attempts have been made to find a mechanism that realises the folding of a three-dimensional pyramid. These attempts led to suggest a design that represents an initial solution for folding the pyramid. It was taken into consideration in this design that the structure should deploy strain free when the thickness of its panels is not considered. Trigonometry was used to find mathematical equations that can be used to identify the lengths and angles of the proposed design plates. These equations theoretically proved the validity of the proposed mechanism. The proposed design was applied to construct an actual model formed with thick panels. Considering the panel thickness of the model plates led to amendments and improvements to the proposed design. Two actual models were experimentally tested to make sure that they achieve the design concepts in the processes of full folding and deployment. The models were also tested in the laboratory to make sure of the integrity of the panel hinges and resistance of the elements to external loading. The model was constructed in a simulation program in order to verify the foldability of the design, folding efficiency and absence of strain or collisions during the process of folding and deployment at all stages.
3

A Bio-Inspired Algorithm and Foldable Robot Platform for Collective Excavation

January 2018 (has links)
abstract: Existing robotic excavation research has been primarily focused on lunar mining missions or simple traffic control in confined tunnels, however little work attempts to bring collective excavation into the realm of human infrastructure. This thesis explores a decentralized approach to excavation processes, where traffic laws are borrowed from swarms of fire ants (Solenopsis invicta) or termites (Coptotermes formosanus) to create decision rules for a swarm of robots working together and organizing effectively to create a desired final excavated pattern. First, a literature review of the behavioral rules of different types of insect colonies and the resulting structural patterns over the course of excavation was conducted. After identifying pertinent excavation laws, three different finite state machines were generated that relate to construction, search and rescue operations, and extraterrestrial exploration. After analyzing these finite state machines, it became apparent that they all shared a common controller. Then, agent-based NetLogo software was used to simulate a swarm of agents that run this controller, and a model for excavating behaviors and patterns was fit to the simulation data. This model predicts the tunnel shapes formed in the simulation as a function of the swarm size and a time delay, called the critical waiting period, in one of the state transitions. Thus, by controlling the individual agents' behavior, it was possible to control the structural outcomes of collective excavation in simulation. To create an experimental testbed that could be used to physically implement the controller, a small foldable robotic platform was developed, and it's capabilities were tested in granular media. In order to characterize the granular media, force experiments were conducted and parameters were measured for resistive forces during an excavation cycle. The final experiment verified the robot's ability to engage in excavation and deposition, and to determine whether or not to begin the critical waiting period. This testbed can be expanded with multiple robots to conduct small-scale experiments on collective excavation, such as further exploring the effects of the critical waiting period on the resulting excavation pattern. In addition, investigating other factors like tuning digging efficiency or deposition proximity could help to transition the proposed bio-inspired swarm excavation controllers to implementation in real-world applications. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2018
4

Development of a Thickness Accommodation Technique for Origami-Inspired Design

Edmondson, Bryce 01 January 2015 (has links) (PDF)
Designers are constantly searching for new sourcing of inspiration for innovative design. Recently, origami has gained interest as one of these potential sources. Origami literally translated from Japanese means “paper folding” where “oru” means “to fold” and “kami” means “paper”. Since paper is insufficient to solve many engineering design problems, designers must turn to other materials. These materials will inevitably be thicker than paper and will often require different folding techniques and considerations. This thesis provides background information describing previous methods to accommodate thickness in origami-inspired design, presents a newly developed technique to address limitations of other methods, and explores the application of the technique. The newly developed technique allows designers to identify a desired motion behavior in an origami model and implement it into a thick mechanism. Many previous methods were incapable of preserving the kinematics and/or restricted usable range of motion. Understanding the capabilities and limitations of thickness accommodation methods empowers designers to better implement inspiration from origami into engineering design. The offset panel technique is further extended to include arbitrary thickness and arbitrary folding plane locations. The technique is verified through creation and testing of hardware, showcasing capabilities and limitations. Demonstration of these capabilities will serve as inspiration for furthering application of thick origami in engineering design. Preliminary work in thick origami led to the design of a thick origami-inspired medical gripper. These origami-inspired forceps, Oriceps, were designed by starting with an origami model exhibiting desired motion, grasping. The Oriceps show some challenges faced with accommodating thickness in adapting an origami model for application.
5

Skládací kontejnery a jejich využití v intermodální přepravě / Foldable Containers and their utilization in Intermodal Transport

Pernikář, Jan January 2013 (has links)
The aim of the thesis is to characterize the folding containers as one of the potential solutions to the problem of the repositioning of empty containers and to evaluate the possibility of their practical use in intermodal transport. The theoretical part characterizes contemporary development in international trade, intermodal transportation, the issue of empty containers and also characterizes foldable containers together with the assumptions of their successful introduction to the market. The practical part deals with current concepts of foldable containers, there is also an example for comparing the costs of transport when using standard or foldable containers and the opinion of a representative of one of the leading shipping companies on use foldable containers in practice. To obtain information used in the practical part of the thesis a secondary research was carried out, where most information comes from research papers and websites, and also primary research was done in the form of an interview with a representative of the shipping company. In conclusion is the evaluation of the possibility of using foldable containers in practice which is based on the information obtained through research.
6

L'"Espace Pliable" : une structure modulable comme capture de moment / The "Foldable Space" : a "modulable" structure as captured time

Magnan, Édith 08 February 2014 (has links)
Afin d'en faire l'expérience, cette thèse explore l'idée d'un espace dit pliable. en tant que « structure modulable comme capture de moment ». L'espace conçu à travers une œuvre n'est pas uniquement envisagé comme le milieu à trois dimensions dans lequel le spectateur se déplace, mais comme l'événement qui interroge et réaffirme sa spatialité. Sans cesse en mouvement parce que pliable sait-on précisément où il se rencontre? Où il se plie et se déplie? Dans le cadre de ma pratique artistique, en développant l'idée d'un Espace Pliable, ces réalisations - à déployer et ployer. à plier et déplier - interrogent aussi bien le volume du point de vue de son extension que le « champ de la sculpture» en expansion. À l'aide d'un corpus d'œuvres allant principalement des années 1960 à nos jours, la thèse liée à ce travail entend repérer et analyser une partie des différentes relations spatiales et temporelles à l'œuvre. Convoquant des artistes tels que Robert Morris, Franz Erhard Walther ou encore Hans-Walter Müller, architecte, l'enjeu de cette recherche est d'étudier l'espace du point de vue de ses particularités plastiques, afin de reconsidérer principalement l'expérience que nous en faisons. Au plus près d'une pratique sculpturale, ces installations entre visible et invisible, matériel et immatériel, ne semblent « capturer» rien d'autre que de l' « espace ». Fortes de l'analyse deleuzienne du pli comme système dynamique - puisque pliable - une fois à l'intérieur de mes sculptures cubiques, celles-ci deviennent un témoin du temps que le spectateur leur donne. / In order to have the experience of it, this thesis explores the idea of what's called Foldable Space, meaning a "modulable structure as captured time". Space represented through an artwork, is not only considered as a three-dimensional environment that the spectator moves through, but as an event which questions and reaffirms its spatiality. Constantly moving, because foldable, do we know precisely where the encounter happens? Where it folds and unfolds? As part of my art practice, developing the idea of a Foldable Space, these works made to be unfurled and bent, folded and unfolded, question both the volume from the perspective of its extension and the expanding "field of sculpture". Using a corpus of works mainly from the 1960s to the present day, the thesis linked to this artwork intends to identify and analyse some of the different spatial and temporal relationships at work. Summoning artists such as Robert Morris, Franz Erhard Walther or the architect Hans-Walter Müller, the imperative of this research is to study space in regard to its sculptural and aesthetic characteristics, mainly in order to reconsider our experience of this space. Very nearly a sculptural practice, these installations between visible and invisible, tangible and intangible, seem "to capture" nothing but "space". Supported by Deleuze's analysis of the fold as a dynamic system - because foldable - once inside one of my cubic sculptures, the sculpture becomes a witness of the time the spectator spends with it.
7

Design and Implementation of Adaptive Morphology Feature for a Tetrahedron Shaped Drone

Wali, Obadah 04 1900 (has links)
In recent years, there has been an increase in the development of drone technologies. Furthermore a considerable interest in developing drones that utilizes platforms allowing for adaptive morphology has been growing steadily. In this work, we use a quadcopter to develop a drone with the feature of transforming its shape from a flat triangle to a tetrahedron. To achieve this property, two main features are considered. First, a controller for the propeller thrust force to control the movement of the triangular side facet. Second, a 60-degree angled bevel gear is used to ensure the positioning concurrency of the facets. In this study, we use MATLAB simulations to study the feasibility of the proposed concept. We use the simulations to determine the base requirement for the controller dynamics by simulating the output angle of the facets and to study the effect of the controllers on the angle reached by the facets. In addition, we perform an experimental analysis to validate our results from the simulations. We investigate the design limitations of the controllers and check the feasibility of the proposed drone design by studying the thrust force generated. The simulations and experiments showed that the presence of bevel gears can reduce the controller dynamics requirement to only a proportional controller. Furthermore, the thrust test for this drone design showed an estimated thrust force of approximately 1.7 times the thrust of a single motor. These results are promising and contribute to setting the foundation for more rigorous study of this design of drones, which have a noticeable impact on the ease of packaging and transportation applications.
8

Incorporating Stability in Deployable Origami-based Engineering Applications

Andrews, David Wayne 01 July 2020 (has links)
For origami-based designs to be functional, they need to be stable. Typically, stability is achieved through the introduction of exterior supports or members. This work focuses on incorporating stability into deployable origami-based engineering applications, including the development of deployable stiffeners or hard stops and generating concepts for stable origami-based systems in specific applications. Two types of deployable stiffeners are developed. Models for transcrease hard stops are presented, which can be directly implemented into origami-patterns to block motion at a specified angle. Thickness Utilizing Deployable Hard Stops (ThUDS), adapted from the transcrease hard stop models, can be implemented into thick materials for use in origami-based design. The application of self-deploying, self-locking ThUDS in an origami-based CubeSat reflectarray is shown, designed using optimization principles. Last, various multistable furniture concepts are presented, with stability incorporated into the concept design. These concepts focus on using composite wood as the base material, due to wood's abundance and commonality in furniture design.
9

SKLADACÍ MESTSKÝ BATOH / FOLDABLE CITY BACKPACK

Štechová, Eva January 2017 (has links)
From the first idea, to research and comparing with other backpacks with foldable function (tele, usárna), and with backpacks associated with urban and streetwear function, I designed a backpack with a practical and functional design which opens questions of personal vs. public space. It plays with the question of lifestyle as a focal point of marketing. It speaks to young people, who spend their time in the city public space and occupy it in their own way. Technical parameters of the backpack are dependent of its functional needs, but the first idea came out of the needs of a modern young nomad, exploring the city public space.
10

Hopfällbar hjullösning / Foldable wheel solution

Jakobsson, Martin, Ringström, Carl January 2013 (has links)
In many products a compromise between ground clearance and the required space to store the product has to be made. This problem attracted the attention of the authors of this thesis.The objective of this project is to develop a functioning solution to a foldable wheel. The solution should be applicable to several types of product groups. A limitation for this work has been made so that the work only covers solutions for lighter vehicles.The purpose is to drive this project forward, so that a solution can be found. Furthermore the purpose of the report is to clarify how the authors proceeded to design and construct the wheel according to a fixed specification. The authors of this project also wishes to develop their knowledge within the field of product development.Set-Based Concurrent Engineering (SBCE) has been used as the underlying method on which this work was based. The work started with a preliminary study. Relevant specifications was established using the results from the study. The specifications was given a rang by the use of pairwise weighting, then a QFD was made using said requirements.The wheel was divided into three different areas. Solutions was developed to problems within each area, independently of one another. The project underwent three concept stages and three screening stages. During the third screening a final concept was chosen for further development.Strength simulations was performed in Solid Works, by using the results from the simulations adjustments to the design could be made.The authors succeeded in developing a wheel capable of a volume reduction by 70 %. When the wheel is dimensioned to fit an ordinary bike it weighs about 2.5kg and can take a radial load of over 1 000N. The final concept is called Arcas and is made up of four sections of a specially developed flexible arc-solution. The arc-solution enables the wheels curved surfaces to be straightened out when the wheel is about be stored.The authors consider that they have developed the knowledge in product development and also improved their ability to handle loose defined projects. It should be possible to further reduce the volume up to levels around 80 %. A detailed FEM analysis of the components should be of use. / Hos många produkter måste en kompromiss göras mellan markfrigång och krävt förvaringsutrymme. Detta problem uppmärksammades av författarna till denna uppsats.Målet med detta projekt är att är att ta fram en fungerande hjullösning på ett hoppfällbart hjul. Lösningen ska gå att applicera inom olika produktgrupper, dock har arbetet begränsats till att endast omfatta lösningar till lättare fordon.Syftet är att driva projektet framåt så att en lösning på problemet hittas. Vidare är syftet med rapporten att redogöra för hur författarna gått tillväga för att designa och konstruera hjulet enligt satta kriterier. Författarna vill även fördjupa sina kunskaper inom produktutveckling.Set-Based Concurrent Engineering (SBCE) har använts som övergripande metod i detta arbete. Arbetsprocessen började med en förstudie. Relevanta krav på produkten upprättades baserade på genomförd förstudie. Kraven viktades genom parvis viktning och en QFD upprättades med dessa krav. Hjulet delades upp i tre olika områden. Lösningar togs fram på problem inom de tre områdena oberoende av varandra. Projektet genomgick tre stycken konceptfaser och tre stycken sållningar. Vid den tredje sållningen valdes ett slutkoncept att arbeta vidare emot.Hållfasthetssimuleringar utfördes sedan i Solid Works, med hjälp av resultaten på dessa kunde justeringar av designen utföras.Författarna lyckades att ta fram ett hjul kapabelt av en volymminskning med 70 %. Då hjulet är dimensionerat för att passa en vanlig cykel väger det ca 2.5kg och klarar av en radiell last på över 1 000N. Det slutgiltiga konceptet heter Arcas och består av fyra sektioner av en speciellt utvecklad flexibel båglösning. Båglösningen tillåter hjulets krökta ytor att rätas ut när hjulet skall förvaras.Författarna anser sig ha fördjupat sina kunskaper inom produktutveckling och framförallt förbättrat förmågan att hantera projekt med lösa ramar. Det borde vara möjligt att öka graden av hoppfällning så att volymminskningen kommer upp i nivåer kring 80 %. En ingående FEM-analys på ingående komponenter skulle vara användbar.

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