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Galos, Joel Luke. "Lightweight composite trailer design." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/263572.
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This thesis explores the use of lightweight composite materials in road freight trailer design as a means of reducing the emissions of the road freight industry. A comprehensive review of previous lightweight composite trailers and related projects was conducted; it concluded that the application of composites in trailers to-date has largely been limited by relatively high material and production costs. The review highlighted that the trailer industry could learn from the success of composites in the bridge construction industry. A statistical weight analysis of two road freight fleets and an energy consumption estimation, via a drive cycle analysis, were used to identify trailers that are particularly suited to lightweighting. Hardwood trailer decking was identified as a prime subcomponent for composite replacement. However, there is little literature on how conventional hardwood trailer decks react to in-service loadings. This problem was addressed through a comprehensive deck damage study, which was used to benchmark novel lightweight deck systems. Several lightweight replacement composite sandwich panels were designed, built and tested. Two different pultruded GFRP decks were also examined. While pultrusions do not offer the same level of weight savings as sandwich panels, the highly cost-driven nature of the trailer industry could dictate that their integration is the most reasonable first step to introducing composites into structural subcomponents. The final part of the thesis explores options for lightweighting the trailer chassis holistically. Trailer load cases were investigated through finite element modelling in Abaqus. A parametric model of a typical longitudinal trailer I-beam was developed using Python scripting and Abaqus. The model was expanded to analyse composite trailer structures. It showed that approximately 1,300 kg of weight could be saved by shape and material optimisation in a composite trailer. In summary, this research has shown that short-term trailer weight reductions can be effectively achieved through subcomponent replacement, while more significant reductions can be achieved in the long-term by a ‘clean slate’ composite redesign of the trailer chassis. The lightweighting strategies presented here are poised to have an increasingly important role in reducing the emissions of the road freight industry.
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Polanco, Hannah Jean. "Structural Lightweight Grout Mixture Design." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6312.
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This research focused on designing a grout mixture using lightweight aggregate that achieves the minimum 28-day compressive strength required for normal-weight grout, 2000 psi. This research specifically studied the effects of aggregate proportion, slump, and aggregate soaking on the compressive strength of the mixture. The variable ranges investigated were 3-4.75 parts aggregate to cement volumetrically, 8-11 in. slump, and 0 and 2 cycles of soaking. The statistical model developed to analyze the significance of variable effects included a three-way interaction between the explanatory variables. All three explanatory variables had a statistically significant effect on the grout compressive strength, but the effect of soaking was minimal and decreased as aggregate proportion decreased. This research also showed that lightweight grout, when prepared using aggregate proportion and slumps within the ranges suggested in American Society for Testing and Materials C476, reaches the required minimum 28-day compressive strength with a factor of safety of at least 2.7.
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Bonnemaison, Sarah. "Lightweight structures in urban design." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/71363.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.
Includes bibliographical references (leaves 83-84).
Lightweight architecture questions how we architects think about the environment. It has qualities which complement "mainstream" buildings. This thesis will explore these qualities and will propose that this architecture is rooted in the modern sensibility and suggests an attitude towards the environment that is needed in our cities. Lightweight architecture is concerned with optimal and, particularly, parsimonious use of materials and effort. Much lightweight architecture is tensile as structures loaded in tension use the least amount of material. Now that modern technology and materials have opened up possibilities· in research and application, much of the research has been done and is no longer the exclusive realm of trained engineers. The question of application of this technology remains -- this is up to the architects. The style of lightweight architecture can be looked at in terms of aesthetic, the process by which one develops its forms and the way of thinking from which it arises. The aesthetic of lightweight architecture enriches the traditional aesthetic notion familiar to us (symmetry, proportion and balance) with the more elusive notions of dynamic symmetry, relative harmony and equilibrium. Form-finding is an experimental process of trial and error. It stems not only from the scientific discipline of static, but from other disciplines , explored from without. In this way, unexpected combinations appear. Complementing static research into the minimal use of materials, vernacular constructions and biology have been used for a greater understanding of parsimony in building. The "logic of reasoning" refers to a creator's conception of the world in which one creates. The designers of lightweight architecture believe in a world not of specialization and analysis, but of creation and adaption, an ecological view of the world. Because the process of creation is more important that the resultant form, the syntactics of structural and formal assembly takes precedence on an analogical basis for form-finding.The second section of this thesis explores lightweight architecture in the city. The current trend of placing lightweight buildings in parks rejects the possibilities of lightweight architecture can offer the city. Many architects see a conflict in the juxtaposition of lightweight buildings against traditional load-bearing urban "fabric". Lightweight architecture implies notions of boundary and mutability that are contrary to these same notions as represented in industrial cities. Being ephemeral, mobile and adaptable, this architecture, by its unboundedness, forces us to re-assess our notion of boundary. Lightweight architecture, allows for a rapid adaption of buildings in the city to climatic change and for the periodic gathering of festivals and markets. The adaptive, mutable qualities lightweight architecture can bring to the city are particularly valuable for urban public spaces. This architecture allows for human engagement with the environment and with each other. The load-bearing wall and its function in the city -- the separation of one activity from another and the definition of privacy -- has been radically redefined by the advent of the glass curtain wall and the telephone. This process has left us with ambiguous urban "public" spaces not much used by the public yet not truly private. Re-introducing a mobile, lightweight ephemeral architecture into post-industrial cities is a desire to implement certain socio-political ideas about city culture and simultaneously make places where those policies are lived.
by Sarah Bonnemaison.
M.S.
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FERREIRA, DANIEL VITOR COSTA. "LEAN COMMUNICATION-CENTERED DESIGN: A LIGHTWEIGHT DESIGN PROCESS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=28670@1.
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O Lean Communication-Centered Design (LeanCCD) é um processo de design de Interação Humano-Computador (IHC) centrado na comunicação, que consiste na realização de um workshop, detalhamento de metas de usuários, combinação de modelos de interação com esboços em papel simulados com usuários, apoiados por guias e quadros. A IHC é uma área que estuda o projeto e uso de tecnologia computacional, em especial a interação entre computadores e pessoas. Este estudo adaptou o Communication-Centered Design (CCD) e o eXtreme Communication-Centered Design (eXCeeD), outros processos de design centrados na comunicação fundamentados na Engenharia Semiótica (EngSem). A EngSem é uma teoria de IHC que define a interação como um processo comunicativo entre designers e usuários mediado por computadores. Abordagens e processos fundamentados nessa teoria buscam favorecer a reflexão através da adoção de modelos, questões e métodos que não gerem diretamente uma resposta ou solução para o problema, mas apoiem o designer na exploração do espaço e da natureza do problema, bem como das restrições sobre soluções candidatas. A avaliação do LeanCCD em um estudo de caso na indústria observou dificuldade na condução das atividades e na aplicação correta de algumas técnicas e conceitos. Porém, diferentemente do eXCeeD, percebemos o uso sistemático das questões que favoreciam a reflexão devido ao auxílio dos quadros e guias propostos.Lean Communication-Centered Design (LeanCCD) is a Human-Computer Interaction (HCI) design process, which consists of conducting a workshop, detailing user goals, combining interaction models with paper sketches, and testing them with users, supported by guides and templates. This study adapted the Communication-Centered Design (CCD) and the eXtreme Communication-Centered Design (eXCeeD), other communication-centered design processes grounded on Semiotic Engineering (SemEng). SemEng defines the interaction as a computer-mediated communication process between designers and users. Approaches and processes based on SemEng are not used to directly yield the answer to a problem, but to increase the problem-solver s understanding of the problem itself and the implication it brings about. Process evaluation in a case study, in the industry, proved itself difficult, both in carrying out LeanCCD activities and in the correct application of some techniques and concepts. However, unlike eXCeeD, we were able to observe a systematic use of questions that contributed to designers reflection, aided by the proposed templates and guides.
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Tugilimana, Alexis. "Optimal design of lightweight modular structures." Doctoral thesis, Universite Libre de Bruxelles, 2018. https://dipot.ulb.ac.be/dspace/bitstream/2013/283383/3/content.pdf.
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This PhD thesis addresses the development of novel computational methods for designing modular structures i.e. structures composed of the assembly of identical components called modules. Current methodologies tackle this challenge by implementing topology optimization of the module but their efficiency is limited by the performance deterioration when numerous modules are used in the structure. In this work, the design of lightweight modular structures is addressed by simultaneously optimizing the topology of the modules and their respective position in the structure. This contribution also includes a novel strategy that reconciles lightness, structural performance, and constructability (i.e. fabrication and erection phases) by incorporating module rotations as additional design variables. To ensure the practical applicability of the proposed approach, stability is included to provide meaningful solutions that are globally stable and resist local buckling. For this purpose, global stability constraints using linear prebuckling are adopted, while local stability is formulated based on Euler buckling and properties of standard profiles obtained from commercial catalogues.Doctorat en Sciences de l'ingénieur et technologie
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Davis, Mark E. (Mark Edward). "Design of a lightweight, multipurpose underwater vehicle." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12646.
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O'Neill, Conor Francis. "Lightweight energy absorbing structures for crashworthy design." Thesis, University of Newcastle upon Tyne, 2018. http://hdl.handle.net/10443/4030.
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The application of lightweight composite materials into the rail industry requires a stepwise approach to ensure rail vehicle designs can make optimal use of the inherent properties of each material. Traditionally, materials such as steel and aluminium have been used in railway rolling stock to achieve the energy absorption and structural resistance demanded by European rail standards. Adopting composite materials in primary structural roles requires an innovative design approach which makes the best use of the available space within the rolling stock design such that impact energies and loads are accommodated in a managed and predictable manner. This thesis describes the innovative design of a rail driver’s cab to meet crashworthiness and structural requirements using lightweight, cost-effective composite materials. This takes the application of composite materials in the rail industry beyond the current state-of-the-art and delivers design solutions which are readily applicable across rolling stock categories. An overview of crashworthiness with respect to the rail industry is presented, suitable composite materials for incorporation into rolling stock designs are identified and a methodology to reconfigure and enhance the space available within rail vehicles to meet energy absorption requirements is provided. To realise the application of composite materials, this body of work describes the pioneering application of aluminium honeycomb to deliver unique solutions for rail vehicle energy absorbers, as well as detailing the use of lightweight composite materials to react the structural loads into the cab and carbody. To prove the capability of the design it is supported by finite element analysis and the construction of a full-scale prototype cab which culminated in the successful filing of two patents to protect the intellectual property of the resulting design.
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Cho, Myung Kyu. "Structural deflections and optical performances of lightweight mirrors." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184875.
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A parametric design study of light weight mirror shapes with various support conditions was performed utilizing the finite element program NASTRAN. Improvements in the mirror performance were made based on the following design criteria: (1) minimization of the optical surface wavefront variations, (2) minimization of the self-weight directly related to cost of manufacturing, and (3) optimal location of support points. A pre-processor to automatically generate a finite element model for each mirror geometry was developed in order to obtain the structural deformations systematically. Additionally, a post-processor, which prepares an input data file for FRINGE (an optical computer code) was developed for generating the optical deflections that lead to the surface wavefront variations. Procedures and modeling techniques to achieve the optimum (the lightest and stiffest mirror shape due to self-weight) were addressed. Fundamental natural frequency analyses, for contoured back mirror shapes for a variety of support conditions, were performed and followed by comparisons of the results which were obtained from NASTRAN and a closed-form approximate solution. In addition, element validity and sensitivity studies were conducted to demonstrate the behavior of the element types provided in the NASTRAN program when used for optical applications. Scaling Laws for the evaluations of the optical performances and the fundamental frequencies were established.
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Gu, Chongyan. "Lightweight physical unclonable functions circuit design and analysis." Thesis, Queen's University Belfast, 2016. https://pure.qub.ac.uk/portal/en/theses/lightweight-physical-unclonable-functions-circuit-design-and-analysis(6b0e0903-ce49-4927-9bb6-e88db530ea67).html.
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With the increasing emergence of mobile electronic devices over the last two decades, they are now ubiquitous and can be found in our homes, our cars, our workplaces etc., and have the potential to revolutionise how we interact with the world today. This has led to a high demand for cryptographic devices that can provide authentication to protect user privacy and data security; however conventional cryptographic approaches suffer from a number of shortcomings. Also, today’s mobile devices are low-cost, low-power, embedded devices that are restricted both in memory and computing power. Hence, conventional cryptographic approaches are typically unsuitable as they incur significant timing, energy and area overhead. Physical unclonable functions (PUFs) are a novel security primitive which utilise the inherent variations that occur during manufacturing processing in order to generate a unique intrinsic identifier for a device. This gives it an advantage over current state-of-the-art alternatives. No special manufacturing processes are required to integrate a PUF into a design lowering the overall cost of the 1C, and everything can be kept on-chip enabling the PUF to be utilised as a hardware root of trust for all security or identity related operations on the device. This enables a multitude of higher level operations based on secure key storage and chip authentication. However, the design and implementation of PUF digital circuits is challenging, particularly for Field Programmable Gate Array (FPGA) devices. Since the circuits depend upon process variations, even small changes in environmental conditions, such as voltage or temperature, or unbalanced design that introduces skew, will affect their performance. In this thesis, a number of novel lightweight PUF techniques are proposed and experimentally validated. Furthermore, previously reported PUF techniques are evaluated and compared with the proposed designs in terms of efficiency and a range of performance metrics.
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Roy, Matthew MacGregor. "Design and fabrication of a lightweight robotic manipulator." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ37282.pdf.
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Yuan, Fenghua. "Lightweight network management design for wireless sensor networks." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/F_Yuan_081307.pdf.
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Baiocchi, Dave. "Design and control of lightweight, active space mirrors." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/290102.
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The success of the Hubble Space Telescope created a great interest in the next generation of space telescopes. To address this need, the University of Arizona (UA) has designed and built several lightweight prototype mirrors ranging in size from 0.5 m to 2 m in diameter. These mirrors consist of three key components: a thin, lightweight glass substrate holds the reflective surface; the surface accuracy is maintained by an array of position actuators; and the stiffness is maintained by a lightweight carbon-fiber/epoxy support structure. The UA mirrors are different from conventional mirrors in that they are actively-controlled: their figure may be changed after they leave the optics shop. This dissertation begins with an overview of the technical issues for placing large optics in space, and I also discuss the current state-of-the-art in active mirror design. Chapters 3 and 4 discuss ways to design mirrors such that the optical performance is maximized while the mass is minimized. Chapter 3 looks at the best way to distribute the mass between the reflective substrate and the actuators, and Chapter 4 looks at the optimum geometries for structured mirrors. The second half of this work looks at the practical aspects of controlling active mirrors. Chapter 5 discusses the University of Arizona's 2 m NMSD prototype mirror. Specifically, I review the system that I developed to measure and control the mirror. I also provide some details on using a least-squares solution to solve for the actuator commands. Chapter 6 discusses the UA ultralightweight 0.5 m prototype mirror. I describe the techniques that I developed for attaching loadspreaders to the reflective surface, the metrology system, and a software package used to remotely-control the mirror.
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Stewart, Andrzej Matthew. "Design and optimization of lightweight space telescope structures." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39709.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.Includes bibliographical references (p. 137-140).
As mankind attempts to look deeper into the universe, increasingly larger space telescopes will be needed to achieve the levels of resolution required to perform these missions. Due to this increase in size, increasing emphasis will be placed on designing lightweight, efficient structures in order to reduce structural mass and minimize launch costs. This thesis discusses several issues related to the design of lightweight space telescopes. Three topics are presented. The first topic deals with the design of a secondary mirror support structure. A simple tripod design is studied and optimized in detail. Several baffle--type designs are also studied and compared to the tripod. Finally, the buckling behavior of the bars in the structures is considered. The second topic deals with localized effects around the attachment points of actuators on a deformable mirror. Using a least-squares method and the coefficient of multiple determination, deformation results from a finite element model are compared to an ideal deformation shape obtained from beam bending theory. Using these results, an optimum set of dimensions is found for the actuator standoff posts that minimizes the deviation of the finite element results from the ideal shape.
(cont.) Finally, the third topic deals with launch loads, which are usually the most severe loads a spacecraft will encounter. A quasi-static launch load analysis procedure is implemented for a finite element model of a hexagonal mirror segment, and a mathematical framework for dynamic analysis is identified. Parameterized, medium-fidelity finite element models are utilized throughout the thesis. These models allow for rapid evaluation of a large number of different designs, and can be used to evaluate large design spaces in order to find optimum designs.
by Andrzej Matthew Stewart.
S.M.
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Liu, Celia H. (Celia Hsin-Hsin). "Structural analysis and design of adaptive lightweight mirrors." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/49907.
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Carruth, Mark Alexander. "Reducing CO2 emissions through lightweight design and manufacturing." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607775.
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Kulkarni, Rohan. "Design of Reliable Lightweight Cast Components : An Optimization Driven Design Appraoch." Thesis, KTH, Maskinkonstruktion (Avd.), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-239573.
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The present-day automotive industry is striving to design lightweight components by optimizing the design for minimization of weight. The topology optimization is used widely for the design of lightweight components. The casting process is time and cost effective for mass production and widely adopted within the automotive industry. Generally, castability is not considered in the weight optimization process. These weight optimized components are optimized once again in the later stage for cost-effectiveness in the casting process. The modified design usually weighs more than the weight optimized design. The design can be optimized for weight and castability simultaneously in the early stage of design and this thesis report presents an optimization process for the same. The optimization process presents effective usage of the topology optimization to design lightweight components without compromising castability. It is a three-step process where thetopology optimization is integrated with solidification simulation along with DFX -castability evaluation. The reliability of the conceptual design is predicted based on the mapping of solidification and stress hotspots. The process is implemented to design three components of Scaniatruck and weight is reduced by 15% to 25%.Dagens bilindustri strävar efter att utforma lätta komponenter genom att optimera designen för att minimera vikt. Topologioptimering används i stor utsträckning för design av lätta komponenter. Gjutningsprocessen är tids-och kostnadseffektiv för massproduktion och allmänt vedertagen inom bilindustrin. Generellt ingår inte gjutbarhet i viktoptimeringsprocessen. Dessa viktoptimerade komponenter optimeras igen i ett senare skede för kostnadseffektivitet vid massproduktion. De flesta gånger är viktoptimerade koncept modifierade för att erhålla kostnadseffektivitet vid gjutning genom att lägga till extra vikt. I den här rapporten presenteras enoptimeringsdriven designprocess för att få pålitlig lättviktsgjutbar design. Optimeringsprocessen presenterar effektiv användning av topologioptimering för att utformalätta komponenter utan att kompromissa med gjutbarheten. Det är en trestegsprocess där topologioptimering integreras med förstärkningssimulering tillsammans med utvärdering avDFX-sårbarhet. Tillförlitligheten hos den konceptuella designen förutses baserat på kartläggningav stelningen och spänninggskoncentrationer. Processen är implementerad för att optimera utformningen av tre komponenter i Scania-lastbilar och vikten minskas med 15% till 25%.
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El, Zareef Mohamed [Verfasser]. "Conceptual and Structural Design of Buildings made of Lightweight and Infra-Lightweight Concrete / Mohamed El Zareef." Aachen : Shaker, 2010. http://d-nb.info/1120864259/34.
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Zareef, Mohamed el [Verfasser]. "Conceptual and Structural Design of Buildings made of Lightweight and Infra-Lightweight Concrete / Mohamed El Zareef." Aachen : Shaker, 2010. http://nbn-resolving.de/urn:nbn:de:101:1-201612041611.
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Descamps, Benoît. "Optimal shaping of lightweight structures." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209362.
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Designing structures for lightness is an intelligent and responsible way for engineers and architects to conceive structural systems. Lightweight structures are able to bridge wide spans with a least amount of material. However, the quest for lightness remains an utopia without the driving constraints that give sense to contemporary structural design.Previously proposed computational methods for designing lightweight structures focused either on finding an equilibrium shape, or are restricted to fairly small design applications. In this work, we aim to develop a general, robust, and easy-to-use method that can handle many design parameters efficiently. These considerations have led to truss layout optimization, whose goal is to find the best material distribution within a given design domain discretized by a grid of nodal points and connected by tentative bars.
This general approach is well established for topology optimization where structural component sizes and system connectivity are simultaneously optimized. The range of applications covers limit analysis and identification of failure mechanisms in soils and masonries. However, to fully realize the potential of truss layout optimization for the design of lightweight structures, the consideration of geometrical variables is necessary.
The resulting truss geometry and topology optimization problem raises several fundamental and computational challenges. Our strategy to address the problem combines mathematical programming and structural mechanics: the structural properties of the optimal solution are used for devising the novel formulation. To avoid singularities arising in optimal configurations, the present approach disaggregates the equilibrium equations and fully integrates their basic elements within the optimization formulation. The resulting tool incorporates elastic and plastic design, stress and displacements constraints, as well as self-weight and multiple loading.
Besides, the inherent slenderness of lightweight structures requires the study of stability issues. As a remedy, we develop a conceptually simple but efficient method to include local and nodal stability constraints in the formulation. Several numerical examples illustrate the impact of stability considerations on the optimal design.
Finally, the investigation on realistic design problems confirms the practical applicability of the proposed method. It is shown how we can generate a range of optimal designs by varying design settings. In that regard, the computational design method mostly requires the designer a good knowledge of structural design to provide the initial guess.
Doctorat en Sciences de l'ingénieur
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Douglas, Adrain Keith. "Mechanical design aspects of a lightweight neonatal retrieval system." University of Southern Queensland, Faculty of Engineering and Surveying, 2005. http://eprints.usq.edu.au/archive/00004105/.
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[Abstract]: This work involves the development of a lightweight, high efficiency, integrated Neonatal Retrieval System consistent with the requirements of medical personnel, with the capability to be loaded into ambulance vehicles without lifting.By studying the current systems in use and surveying the potential end users a basic specification is established. From this specification concepts are cultivated and, withregular input from end users, developed into a working prototype. This prototype is tested to the required standards and assessed by the end users. Following positivefeedback, a clinical trial is undertaken by medical personnel who confirm that the new system addresses many of the operational problems encountered with currentequipment.It is concluded that with further refinement and sufficient commercial backing, this new Neonatal Retrieval System would improve the process of neonatal retrieval inthis country and possibly internationally. This has the potential to improve outcomes for both patients and the medical personnel who conduct these retrievals.
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Nie, Yi. "Advanced analysis and lightweight design of annular extrusion dies." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49684/.
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Annular extrusion dies have been widely used for the production of plastic pipes and tubes. But they are usually designed according to engineering experience which has led to the overweight and waste in material of them. With increasingly stringent environmental regulations in many countries, attaining lightweight design of mechanical parts and components becomes an ever-lasting goal of designers during design process. Thus a systematic lightweight design methodology which integrates the tools of numerical simulation, structural optimization and life cycle assessment is proposed for annular extrusion dies in the thesis. The implementation of the lightweight design depends on the numerical simulation to model the coupled fluid-thermal-structural process of a typical extrusion operation. The simulation begins with the prediction of the rheological behaviours of polymer melts flowing through an annular extrusion die. The essential flow characteristics including velocity, pressure drop, wall shear stress and temperature are investigated. The Smart Bucket Surface mapping algorithm is then applied to transfer the temperature and pressure loads on flow channel for the following thermal and structural analysis of the extrusion die. The finite element analysis software ANSYS workbench 15.0 is used to calculate the temperature, deformation and thermal stress distribution of the die body. The effects of structure parameters and processing parameters on both the flow pattern of polymer melts and the mechanical properties of the die body are further investigated. Besides, a deformation and high temperature stress measurement system for the extrusion die is constructed using the corresponding sensors and data logger. The measurement results are compared with the simulation results which indicates the effectiveness of the proposed numerical model. Lightweight design of the extrusion die is then conducted using structural optimization. The design parameters and their threshold values which indicate the required performances of productivity, static stiffness, static strength, and manufacturability are identified according to the above numerical simulation results. The Adaptive Response Surface Method (ARSM) is used to solve the optimization scheme to achieve the targeted design parameters with minimum mass. The so-called lightweight coefficient is employed to characterize and evaluate the lightweight designed extrusion die. An extrusion die design example is solved by applying the design criterion of reducing the thickness of die wall. The results show that the structural lightweight design can significantly reduce the weight and increase the lightweight coefficient of extrusion die. To evaluate the effect of lightweight design on the environmental performances of the extrusion die, the life cycle assessment (LCA) is conducted. The stages of life cycle are composed of material stage, manufacture stage, use stage and end of life (EOL) stage. The environmental impacts (EIs) of the extrusion die are modelled as a function of geometrical and processing parameters. The EIs between the original and lightweight designed extrusion die are compared which shows that the proposed lightweight design method has a contribution to both material reduction and EIs of the extrusion die in the entire life cycle. It is foreseeable that the work in the thesis provides a foundation for dealing with lightweight design of conventional heavy duty machine components with complex functionalities.
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Daniel, Ajay. "Suspension design for Uniti, a lightweight urban electric vehicle." Thesis, KTH, Fordonsdynamik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234900.
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Climate change is real and the automotive industry is no longer in denial that electrification of vehicles is the future. But what if there is a better solution to meeting the commuting requirements in an urban environment than a form of a car that we are so familiar with? Something which gives the freedom of mobility like a car but is more practical. Perhaps a Uniti? Uniti aims at providing a smart solution to urban commute, something which is sustainable, fun and in step with the strides made in technology. This involved starting from a clean slate and attacking the very fundamental problem; a two-ton machine meant for carrying four to five people being used by only one person for majority of its lifespan, which makes all the more less sense in an urban environment. Hence came into life Uniti; a lightweight electric vehicle in the L7e category designed to be the second family car. Designing such a vehicle from the standpoint of vehicle dynamics is tricky as the user shapes the mass of the vehicle significantly. The driver and passenger in this vehicle accounts for almost a quarter of the total weight. That along with the high unsprung mass coming with the use of in wheel electric motors makes this project all the more challenging. The thesis is aimed at providing a starting point to build on to a robust suspension design. The fundamentals of vehicle dynamics were used to build up mathematical models in MATLAB and simulations were done with ADAMS/Car to study and optimize the design. All said and done the scope of the work was limited considering it had to be built from scratch but the models developed and the concepts laid out would hopefully be a good foundation to develop it into the prefect one.Klimatförändringarna är verkliga och bilindustrin kan inte längre förneka att elektrifiering av fordon är framtiden. Men vad händer om det finns en bättre lösning för att uppfylla pendlingskraven i en stadsmiljö än en form av bil som vi är så bekanta med? Något som ger fri rörlighet som en bil men är mer praktisk. Kanske en Uniti? Uniti har som målsättning att erbjuda en smart lösning för urban pendling, något som är hållbart, roligt och i takt med de framsteg som gjorts inom tekniken. Detta innebar att man startade från ett tomt papper och attackera det mycket grundläggande problemet; en två ton maskin som är avsedd att bära fyra till fem personer som används av endast en person för majoriteten av sin livslängd, vilket är mindre önskvärt i en stadsmiljö. Därför kom Uniti till livet; ett lätt elfordon i L7e-kategorin som är konstruerad för att vara den andra familjebilen. Att utforma ett sådant fordon utifrån fordonets dynamik är svårt eftersom användaren förändrar fordonets massa väsentligt. Föraren och passageraren i detta fordon står för nästan en fjärdedel av den totala vikten. Detta tillsammans med den höga ofjädrade massan pga hjulmotorer gör det mer utmanande. Examensarbetet syftar till att skapa en utgångspunkt att bygga vidare på för en robust hjulupphängningsdesign. Grunder i fordonsdynamik användes för att bygga upp matematiska modeller i MATLAB och simuleringar gjordes med ADAMS / Car för att studera och optimera designen. Arbetets omfattning var begränsat med tanke på att allt behövde byggas från början, men modellerna som utvecklats och de koncept som lagts fram ska förhoppningsvis vara en bra grund för att utveckla vidare.
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Amir, Bourak Maher. "An Integrated Method Of Lightweight Design, Optimization, and Bionics." Thesis, Högskolan i Halmstad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42252.
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The main objective of the current study was to examine the trends and current status of lightweight design, optimization, and bionics in industrial applications. The goal wasto explore the suitable innovations used by industrial companies to ensure improved product performance and low costs of manufacturing. To achieve the goal, a secondary research methodology was employed in which seven studies on the topics of optimization, bionics, and lightweight designs were sampled and analyzed. A key resultnoted was that lightweight design is achieved through the use of magnesium alloys,aluminum alloys, and non-metallic materials such as carbon fiber-reinforced polymer.To optimize performance of the lightweight materials, computer technologies such as computer-assisted designs (CAD) are being used to ensure that the best shapes of the materials are utilized to offer the best performance. Meanwhile, bionics was employed by creating product designs which are inspired by nature such as meshless structures that minimize energy consumption, are cheaper, and are environmentally friendly.
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Magnusson, Tobias. "Conceptual sandwich-sandwich-steel joint design for lightweight rail vehicle." Thesis, KTH, Lättkonstruktioner, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159283.
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In order to find a feasible solution for a joining method of a sandwich side-wall, a sandwichfloor and a steel underbody of a railway vehicle, conceptual joint designs have been devel- oped by using structural optimization software. It is shown that the joints are capable of carrying the loads assumed to act on the structure but that several improvements to theanalysis needs to be done to assure a safe design.
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Montgomery, Robert H. (Robert Hall). "Design and analysis of a lightweight parallel cable-controlled manipulator." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14687.
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González, Gabriel J. (Gabriel Joe) 1980. "Design of a compact, lightweight, and low-cost solar concentrator." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32813.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references.
The objective of this mechanical design project was to improve the current design of large and heavy solar concentrators. The three main design goals were: making the system compact, making the system lightweight, and minimizing expenses. The main approach to achieving these design parameters was to use the plastic film Mylar in its aluminized form to create a paraboloid serving as a solar concentrator. The scope of design was limited to designing and prototyping the solar concentrator, and neglecting to design and prototype the container in which it should be kept while in its compact form. Two designs-the tube design and the rim design-are examined, although the rim design is emphasized because of its advantages over the tube design. The tube design included a bicycle tire tube serving as the structural element of the solar concentrator, while the rim design utilized a bandsaw blade (without teeth) as the structural element of the solar concentrator. The prototype of the rim design proved to work well as a mirror, although further work, such as improving the seal around the rim, must still be done due to the time frame and resources allowed for this project.
by Gabriel J González.
S.B.
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Qiu, Kepeng. "Analysis and optimal design of lightweight sandwich structures and materials." Besançon, 2008. http://www.theses.fr/2008BESA2046.
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La thèse concerne les performances de l’analyse et de l’optimisation de structures composites légères du type “solides cellulaires et sandwich”. Une étude spécifique est consacrée à l’optimisation topologique de solides cellulaires à périodicité. La méthode de super-élément est développée et appliquée à l’analyse statique et dynamique de plaques composites en considérant l’influence de la topologie et des dimensions de cellules périodiques constituant la structure. La méthode multi-phase d’homogénéisation 3D est appliquée pour calculer les propriétés élastiques équivalentes de structures nid d’abeille. Ensuite, une méthode inverse d’homogénéisation est appliquée pour obtenir une configuration de la microstructure. Elle concerne la maximisation de propriétés élastiques ainsi que de conductivités thermiques. L’optimisation topologique est mise en œuvre pour maximiser la rigidité globale des structures cellulaires comprenant les cellules carrées ou cylindriques à symétrie cyclique. Tous les éléments volumiques représentatifs (RVE – representative volume element) d’une structure cellulaire périodique sont modélisés en utilisant la méthode de super-élément (SE). La technique de liaison des variables d’optimisation est utilisée pour la périodicité dans les structures optimales. Les différentes configurations optimales RVE-SE étudiées permettent d’illustrer l’influence du paramètre d’échelle entre RVE et SE sur le processus d’optimisation. Des relations entre les dimensions d’une cellule et le nombre de cellules dans une plaque avec différentes conditions aux limites et leurs influences sur les solutions optimales en statique et en dynamique sont étudiéesThe thesis deals with the performance analysis and the topology design of lightweight cellular solids and sandwich structures. Special emphasis is devoted to the topological optimization of periodic cellular solids based on the super-element method. The bending static and dynamic analysis and the core design of sandwich panels considering the size effect of cells is developed. The multi-step homogenization method is applied to calculate the effective elastic constants of multi-layered 3D honeycomb sandwich. The effective results are credible by comparison with other methods including classical formula, energy method and engineering empirical method. An integrated topology optimization procedure is developed for the global stiffness maximization of different cellular solids such as cyclic-symmetry square and cylinder structures. Each RVE (representative volume element) of periodic cellular solids is modeled by the SE (super-element) method. The technique of linking the design variables is adopted to ensure the periodicity of the optimal configuration over the whole structure after optimization. The various optimal configurations permit to illustrate the influence of size variation of RVE-SE on the optimal results. The computational efficiency is studied during the optimization process when the super-element method is adopted. A special study on the size effect is carried out for the bending static and dynamic analysis of the core design of sandwich panels. Special attention is devoted to the influence of size effect on the optimal results
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Zambujeiro, Vítor Miguel Mata. "Intelligent lightweight Design na optimização de uma máquina de ponte." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2446.
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Mestrado em Engenharia MecânicaCom este trabalho pretende-se desenvolver e optimizar estruturalmente o projecto e os accionamentos do módulo base do equipamento actualmente de maior sucesso da cei, a StoneCut. A StoneCut“Máquina de Ponte Inteligente”, está na vanguarda do corte de chapa de pedra por disco diamantado erepresenta um grande avanço no processamento e corte de chapa de pedra.Além da apresentação de soluções melhoradas para os elementos móveis erespectivos accionamentos dos eixos deste equipamento, pretende-se também adquirir um maior domínio dos princípios que determinam a sua concepção eprojecto, de forma a reforçar - e ampliar - a posição de liderança da ceino mercado dos equipamentos de processamento e corte de chapa de pedra. ABSTRACT: It is the intention of this work to develop and optimize the structure and lineardrive power of the basic module of cei’s most successful equipment, the StoneCut. The StoneCut“Intelligent Power Bridge Machine” is in the van of stone slab circular saw cutting equipments and represents a major advance inslab processing and cutting methods. Besides the analysis, development andimplementation of improved solutions for moving elements and respectivepower drives of this equipment drive axis, it is also a goal of this work to have the upper hand of the principals who determinates the conception andmechanical design in way to reinforcement and amplify cei´s leadership position in the market of stone slab processing and cutting equipment.
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Tyagi, Sheetanshu Rajeev. "Development of a Semi Active Suspension System for Lightweight Automobiles." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72131.
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Vehicle suspension systems play an integral role in influencing the overall performance of a vehicle. The suspension system of a vehicle performs multiple tasks, such as maintaining contact between the tires and the road and isolating the frame of the vehicle from road-induced vibration and shocks. A significant amount of research has been directed to improving the performance of the suspension system by varying the damping coefficient so as to alter the frequency response of the system.
This study describes the development of such a damper. The goal of this research has been to design, model, fabricate and test a novel semi-active damper. The damper consists of two independent electronically controlled units placed in series with one another. The system was initially simulated using a 2 DOF quarter-car model and the performance characteristics of the damper were outlined. Following that, multiple design iterations of the damper were created and a MATLAB/Simulink model was used to simulate physical and flow characteristics of the damper. After the design and analysis was complete, the damper was fabricated and tested using a shock dyno at CenTiRe. The test results were then compared to the simulation results so as to confirm performance of the damper. Additionally, the results obtained on the dyno were then compared against that of a relative single semi-active and passive damper.Master of Science
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Ritter, Robin. "The 100 kW Sportscar : Experience-Oriented Performance through Reduction in Times of Excess." Thesis, Umeå universitet, Designhögskolan vid Umeå universitet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-136849.
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Problem Area With the introduction of the Bugatti Veyron in 2005, a new breed of sportscars was born: the hypercar. It was celebrated as a technological masterpiece, its todays hybrid counterparts, the McLaren P1, Ferrari LaFerrari and Porsche 918 Spyder were named the ‘holy trinity’ of sportscars. However, only a few hundreds of these cars will ever be built, and most enthusiasts will only be able to experience their performance in the virtual world in a racing simulator. The few lucky owners though face a similar problem: These machines are so fast and their traction limit is so high that they can hardly be driven flat-out on open roads, which turns many of them into a track-only toys or garage queens. Design process The design process used is fairly traditional, starting with a research phase, an ideation phase which is being followed by a refinement phase and ultimately the execution of the design in form of a physical scale model and digital renderings. However it needs to be stated that the availability of VR reviews already has a very positive impact on the design workflow. Many design solutions, ergonomics and proportions were modeled directly in 3D and immediately tested in VR, similar to a continously updated 1:1 clay model in the industry. Final result The final result is a lightweight sportscar that makes most out of its limited power resources. Not only does it use state-of-the art technologies and materials to be as efficient as possible, it also boosts the driving experience with several innovative design solutions. The styling is modern and in line with Porsche’s carefully developed current design DNA, but also links to the past. Connaisseurs of the Porsche heritage will find several references to models from the past, yet all these elements are respectfully interpreted in a contemporary yet timeless way. Other, more high-volume manufacturers also produce versions of their models with ridiculously powerful engines - similar to the era of the muscle cars in the late 60ies. In some cases, it seems that this is more of an engineers game of numbers, a marketing strategy or a method to please the ego of the companies’ board members. The fun of sportscar driving however is where the driver and or the machine reach their physical limits - in speed, revs, reaction time, grip and g-forces. Finding and riding along on this edge is the challenge of driving a sportscar, and this project claims that this can be brought back to a level that is far below that of hypercars. The challenge of this project is therefore to develop a car that can deliver an exciting, memorable driving experience with less financial, energy and material resources. At the same time, in an age of Uber, Lyft and the advent of autonomous vehicles, this car should attract younger customers to keep the following generations interested in the driving aspect of cars, a key factor in the emotionality that ultimately leads to higher profits for the manufacturer and above all, an exciting leisure time experience for the customer. Design process The design process used is fairly traditional, starting with a research phase, an ideation phase which is being followed by a refinement phase and ultimately the execution of the design in form of a physical scale model and digital renderings. However it needs to be stated that the availability of VR reviews already has a very positive impact on the design workflow. Many design solutions, ergonomics and proportions were modeled directly in 3D and immediately tested in VR, similar to a continously updated 1:1 clay model in the industry. Final result The final result is a lightweight sportscar that makes most out of its limited power resources. Not only does it use state-of-the art technologies and materials to be as efficient as possible, it also boosts the driving experience with several innovative design solutions. The styling is modern and in line with Porsche’s carefully developed current design DNA, but also links to the past. Connaisseurs of the Porsche heritage will find several references to models from the past, yet all these elements are respectfully interpreted in a contemporary yet timeless way.
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Park, Sarah S. "Biomimicry of Feathers for Airport Design." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1493714938210786.
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Stephan, Pascal. "Suitable bonding method of a multi-material glove compartment for lightweight design." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-12583.
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Within the framework of this Final Year Project in Mechanical Engineering an investigation is done for a Suitable Bonding Method for a Multi-Material Glove Compartment for Lightweight Design. The industrial partner of this Project is Swedfoam. Decreasing fuel consumption and lowering the carbon foot print for automobiles, lightweight construction is one of the key factors to achieve these regulations and more crucial these aims as future needs. Often a simple idea already has a great potential, such as replacing conventional materials with lighter ones in certain applications. Exactly this is done for the lid of a glove compartment; a metal plate, used as a core of the application beforehand is disposed and replaced with a composite, which decreases the weight of the lid significantly. A problem is faced with the new design of the inner lid of a glove compartment, because due to the lighter material the joining method is changed to bonding. Previously the bonding failed mainly due to temperature changes. A literature survey on the material data is done, as well as lab experiments on the used composite in order to characterize crucial material parameters required for the occurred problems when using bonding as joining method. The results from the experiments and literature survey are used to simulate different bonding methods with the commercial software Abaqus. Results from the simulation are presented using adhesive and tape as bonding methods. Finally it is shown, that it is most important for a successful bonding, where or respectively on which surfaces the bonding is done.
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Cohan, Lucy Elizabeth. "Integrated modeling to facilitate control architecture design for lightweight space telescopes." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40307.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 161-167).
The purpose of this thesis it to examine the effects of utilizing control to better meet performance and systematic requirements of future space telescopes. New telescope systems are moving toward tighter optical performance requirements with lower mass and cost, creating an implicit conflict for currently designed systems. Therefore, new technology and telescope types must be developed and implemented, and a key to lightweight systems is the addition of controls. This thesis uses an integrated modeling technique to examine a large tradespace of space telescope systems. The analysis techniques includes finite element and dynamic disturbance analyses to determine the effects of various parameters on overall system performance metrics. In particular, this thesis will focus on the control system architecture for future space telescopes. As systems become less massive, more control is necessary to meet the performance requirements. Less massive systems have more flexibility, which degrades performance. Thus, this flexibility must be controlled to obtain adequate performance. However, the control also has a cost that must be considered.
(cont.) As the areal density of the mirror decreases, the cost due to mass decreases, but the cost due to control increases because more control is required to meet the requirements. Therefore, a balance between lightweight systems and control is sought to give the best overall performance. Additionally, there are many different types of control that could be used on the system, thus finding optimal combinations of controllers, sensors, actuators, and bandwidths is a daunting task. The integrated modeling technique allows the designer to examine the effects of structural parameters and requirements on the control system architecture and the performance metrics. The ability to determine favorable control system architectures early in the design process will allow new technologies to be pushed further, while still maintaining confidence that the system will perform as expected.
by Lucy Elizabeth Cohan.
S.M.
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Sampaio, Zodinio Laurisa Monteiro. "Low cement structural lightweight concrete with optimized multiple waste mix design." PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, 2017. https://repositorio.ufrn.br/jspui/handle/123456789/24353.
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The high-energy demand involved in the construction industry and the increasing consumption of concrete made this material an ideal option for the recycling of by-products from various industries such as: porcelain polishing residue (PPR); tire rubber residue (TRR) and limestone residue (LSR). These residues often lack a treatment that contributes to the degradation of the environment. In this sense, the use of by-products that increases the volume of the concrete without damaging significantly its properties, can be a viable option in the production of low-cost and sustainable low-weight concrete (LWC). The main objective of this work was to analyze the mechanical and thermal behavior of structural lightweight concrete (SLWC) with low cement consumption, produced with expanded clay (EC) in replacement of the aggregate and with the addition of PPR, TRR and LSR to replace the small aggregate. For this purpose, a 2? factorial design was used for the choice of SLWC with the best performance in terms of consistency, mechanical properties and density. Subsequently, reductions of 10, 20 and 30% of cement were performed on SLWC that presented better combination of properties and waste consumption and were characterized by mechanical tests. The best SLWC mix resulting from the combination of mechanical properties and cement consumption was characterized by permeability, flexural strength, TG/DTA, XRF, SEM, thermal capacity, thermal conductivity and thermal diffusivity. The results showed that residues contents around 21% presented better combination of properties. By maintaining the amount of residue at optimum levels it was possible to produce a SLWC with good rheological, mechanical and thermal properties with minimum cement consumption.
A alta demanda energ?tica envolvida na ind?stria da constru??o civil e o crescente consumo do concreto, fez com que o concreto se tornasse a op??o ideal para a reciclagem de subprodutos de v?rias industrias tais como: res?duo de polimento de porcelanato PPR; res?duo de borracha de pneu (TRR) e res?duo de pedra calc?ria (LSR). Esses res?duos frequentemente carecem de um tratamento adequando o que acaba contribuindo para a degrada??o do meio ambiente. Nesse sentido, o uso de subprodutos que ir?o aumentar o volume do concreto sem prejudicar muito as propriedades, pode ser uma op??o bastante vi?vel na produ??o de Concretos leves (CL) de baixo custo e sustent?veis. O objetivo geral desse trabalho foi analisar o comportamento mec?nico e t?rmico de concretos leves estruturais (CLE) de baixo teor de cimento produzidos com argila expandida (AE) em substitui??o ao agregado gra?do e com adi??o de PPR, TRR e LSR em substitui??o a parte do agregado mi?do. Para tal foi usado inicialmente um planejamento fatorial 2? para a escolha dos CLE com melhor desempenho em termos de consist?ncia, propriedades mec?nicas e massa espec?fica real. Posteriormente foram realizadas redu??es de 10, 20 e 30% de cimento nos CLE que apresentaram melhores desempenhos e caracterizados atrav?s de ensaios mec?nicos. O melhor tra?o resultante da combina??o de propriedades mec?nicas com o consumo de cimento foi caracterizado mediante ensaios de: permeabilidade; resist?ncia ? flex?o; TG/DTA; FRX; MEV; capacidade t?rmica; condutividade t?rmica e difusividade t?rmica. Por fim. Os resultados mostraram que teores de res?duos em torno de 21% apresentaram melhor combina??o de propriedades. Mantendo os teores de res?duos em n?veis ?timos foi poss?vel produzir um CLE com boas propriedades reol?gicas, mec?nicas e t?rmicas com um consumo m?nimo de cimento.
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Portella, Rodrigo. "Balancing energy, security and circuit area in lightweight cryptographic hardware design." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEE036/document.
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Cette thèse aborde la conception et les contremesures permettant d'améliorer le calcul cryptographique matériel léger. Parce que la cryptographie (et la cryptanalyse) sont de nos jours de plus en plus omniprésentes dans notre vie quotidienne, il est crucial que les nouveaux systèmes développés soient suffisamment robustes pour faire face à la quantité croissante de données de traitement sans compromettre la sécurité globale. Ce travail aborde de nombreux sujets liés aux implémentations cryptographiques légères. Les principales contributions de cette thèse sont : - Un nouveau système d'accélération matérielle cryptographique appliqué aux codes BCH ; - Réduction de la consommation des systèmes embarqués et SoCs ; - Contre-mesures légères des attaques par canal auxiliaire applicables à l'algorithme de chiffrement reconfigurable AES ;- CSAC : Un pare-feu sécurisé sur la puce cryptographique ; - Attaques par analyse fréquentielle ; - Un nouveau protocole à divulgation nulle de connaissance appliquée aux réseaux de capteurs sans fil ; - OMD : Un nouveau schéma de chiffrement authentifiéThis thesis addresses lightweight hardware design and countermeasures to improve cryptographic computation. Because cryptography (and cryptanalysis) is nowadays becoming more and more ubiquitous in our daily lives, it is crucial that newly developed systems are robust enough to deal with the increasing amount of processing data without compromising the overall security. This work addresses many different topics related to lightweight cryptographic implementations. The main contributions of this thesis are: - A new cryptographic hardware acceleration scheme applied to BCH codes; - Hardware power minimization applied to SoCs and embedded devices; - Timing and DPA lightweight countermeasures applied to the reconfigurable AES block cipher; - CSAC: A cryptographically secure on-chip firewall; - Frequency analysis attack experiments; - A new zero-knowledge zero-knowledge protocol applied to wireless sensor networks; - OMD: A new authenticated encryption scheme
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de, Fluiter Travis. "Design of lightweigh electric vehicles." The University of Waikato, 2008. http://hdl.handle.net/10289/2438.
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The design and manufacture of lightweight electric vehicles is becoming increasingly important with the rising cost of petrol, and the effects emissions from petrol powered vehicles are having on our environment. The University of Waikato and HybridAuto's Ultracommuter electric vehicle was designed, manufactured, and tested. The vehicle has been driven over 1800km with only a small reliability issue, indicating that the Ultracommuter was well designed and could potentially be manufactured as a solution to ongoing transportation issues. The use of titanium aluminide components in the automotive industry was researched. While it only has half the density of alloy steel, titanium aluminides have the same strength and stiffness as steel, along with good corrosion resistance, making them suitable as a lightweight replacement for steel components. Automotive applications identified that could benefit from the use of TiAl include brake callipers, brake rotors and electric motor components.
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Demircubuk, Murat. "Design and manufacture of optimum porduct structure /." View online ; access limited to URI, 2005. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3188839.
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Martirosyan, Anahit. "Towards Design of Lightweight Spatio-Temporal Context Algorithms for Wireless Sensor Networks." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19857.
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Context represents any knowledge obtained from Wireless Sensor Networks (WSNs) about the object being monitored (such as time and location of the sensed events). Time and location are important constituents of context as the information about the events sensed in WSNs is comprehensive when it includes spatio-temporal knowledge.
In this thesis, we first concentrate on the development of a suite of lightweight algorithms on temporal event ordering and time synchronization as well as localization for WSNs. Then, we propose an energy-efficient clustering routing protocol for WSNs that is used for message delivery in the former algorithm.
The two problems - temporal event ordering and synchronization - are dealt with together as both are concerned with preserving temporal relationships of events in WSNs. The messages needed for synchronization are piggybacked onto the messages exchanged in underlying algorithms. The synchronization algorithm is tailored to the clustered topology in order to reduce the overhead of keeping WSNs synchronized.
The proposed localization algorithm has an objective of lowering the overhead of DV-hop based algorithms by reducing the number of floods in the initial position estimation phase. It also randomizes iterative refinement phase to overcome the synchronicity of DV-hop based algorithms. The position estimates with higher confidences are emphasized to reduce the impact of erroneous estimates on the neighbouring nodes.
The proposed clustering routing protocol is used for message delivery in the proposed temporal algorithm. Nearest neighbour nodes are employed for inter-cluster communication. The algorithm provides Quality of Service by forwarding high priority messages via the paths with the least cost. The algorithm is also extended for multiple Sink scenario.
The suite of algorithms proposed in this thesis provides the necessary tool for providing spatio-temporal context for context-aware WSNs. The algorithms are lightweight as they aim at satisfying WSN's requirements primarily in terms of energy-efficiency, low latency and fault tolerance. This makes them suitable for emergency response applications and ubiquitous computing.
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Willis, Darrin. "Design and development of a novel lightweight long-reach composite robotic arm." Thesis, UOIT, 2009. http://hdl.handle.net/10155/27.
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Metallic robotic arms, or manipulators, currently dominate automated industrial operations, but
due to their intrinsic weight, have limited usefulness for large-scale applications in terms of
precision, speed, and repeatability. This thesis focuses on exploring the feasibility of using
polymeric composite materials for the construction of long-reach robotic arms. Different
manipulator layouts were investigated and an ideal design was selected for a robotic arm that has
a 5 [m] reach, 50 [kg] payload, and is intended to operate on large objects with complex
curvature.
The cross-sectional geometry of the links of the arm were analyzed for optimal stiffness- and
strength-to-weight ratios that are capable of preserving high precision and repeatability under
time-dependent external excitations. The results lead to a novel multi-segment link design and
method of production.
A proof-of-concept prototype of a two degrees-of-freedom (2-DOF) robotic arm with a reach of
1.75 [m] was developed. Both static and repeatability testing were performed for verification.
The results indicated that the prototype robot main-arm constructed of carbon fiber-epoxy
composite material provides good stiffness-to-weight and strength-to-weight ratios. Finite
element analysis (FEA) was performed on a 3-D computer model of the arm. Successful
verification led to the use of the 3-D model to define the dimensions of an industrial-sized robotic
arm. The results obtained indicate high stiffness and minimal deflection while achieving a
significant weight reduction when compared to commercial arms of the same size and capability.
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Qi, Gang 1971. "Optimal design of a lightweight robotic manipulator using carbon fibre-reinforced composites." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82626.
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One of the most attractive applications of composite materials is in robot industry. The reason lies in the fact that lightweight composite materials with excellent performance can dramatically overcome the tricky conflict of simultaneously achieving high end-effector positional accuracy and high link acceleration. This thesis describes the process of analysis and redesign of an anthropomorphic parallel robotic manipulator using graphite/epoxy fiber reinforced composites, which exhibit high stiffness-to-weight ratio and strength-to-weight ratio as well as good damping properties. From the structural viewpoint, by means of finite element analysis, the research into the composite robot arms covers the following aspects: redesign and shape optimization of the robot arms using shell structures; optimizing stacking sequence and fiber orientations for composite laminates; incorporating metal inserts into composite structures to improve local stress concentrations and modal analysis to ensure the high dynamic characteristics of the newly developed structures. Comparing with the original design using metal links, the improved composite counterpart significantly increased the stiffness of the robot arm while decreasing their mass and inertia to achieve a very high specific stiffness, specific strength and excellent dynamic performance.
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Mukundan, Sudharsan. "Structural design and analysis of a lightweight composite sandwich space radiator panel." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1613.
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The goal of this study is to design and analyze a sandwich composite panel with lightweight graphite foam core and carbon epoxy face sheets that can function as a radiator for the given payload in a satellite. This arrangement provides a lightweight, structurally efficient structure to dissipate the heat from the electronics box to the surroundings. Three-dimensional finite element analysis with MSC Visual Nastran is undertaken for modal, dynamic and heat transfer analysis to design a radiator panel that can sustain fundamental frequency greater than 100 Hz and dissipate 100 W/m2 and withstand launch loads of 10G. The primary focus of this research is to evaluate newly introduced graphite foam by Poco Graphite Inc. as a core in a sandwich structure that can satisfy structural and thermal design requirements. The panel is a rectangular plate with a cutout that can hold the antenna. The panel is fixed on all the sides. The objective is not only to select an optimum design configuration for the face sheets and core but also to explore the potential of the Poco foam core in its heat transfer capacity. Furthermore the effects of various parameters such as face sheet lay-up, orientation, thickness and material properties are studied through analytical models to validate the predictions of finite element analysis. The optimum dimensions of the sandwich panel are determined and structural and thermal response of the Poco foam is compared with existing aluminum honeycomb core.
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Evans, Thomas H. "Design of composite sandwich panels for lightweight applications in heavy vehicle systems." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4745.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains ix, 125 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 124-125).
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Frushour, John H. "Design considerations for a computationally-lightweight authentication mechanism for passive RFID tags." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FFrushour.pdf.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Fulp, J.D. ; Huffmire, Ted. "September 2009." Description based on title screen as viewed on November 6, 2009. Author(s) subject terms: Passive RFID Systems, Tags, Clock, Electro-magnetic induction, authentication, hash, SHA--1. Includes bibliographical references (p. 59-60). Also available in print.
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Jordan, Elizabeth (Elizabeth O. ). "Design and shape control of lightweight mirrors for dynamic performance and athermalization." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39705.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.Includes bibliographical references (p. 121-124).
The next generation of space telescopes will need to meet increasingly challenging science goals. For these new systems to meet resolution goals, the collecting area of the primary mirror will need to be increased. However, current space telescope designs are reaching their limits in terms of size and mass. Therefore, new systems will need to include technologies such as lightweight mirrors, segmented or sparse apertures and active optical control. Many of these technologies have no flight heritage, so determining what combinations of technologies will create favorable designs requires detailed modeling and analysis. This thesis examines the design of a lightweight mirror for an advanced space telescope for both dynamic performance and shape control. A parametric model of a rib-stiffened mirror is created in order to quickly analyze many different mirror geometries. This model is used to examine the homogeneous dynamics of the mirror to determine what geometry will maximize the ratio of stiffness to areal density. The mirror model is then used in a full dynamic disturbance-to-performance analysis so that system performance can be examined as a function of changes in the mirror geometry.
(cont.) Next, a quasi-static shape control algorithm is developed to control the mirror using in the presence of thermal disturbances. The traditional method of mirror shape control relies on feedback from 'a wavefront sensor in the optical path. A wavefront sensor reduces the amount of light available for image formation, which causes problems when viewing very dim objects. Therefore, this control algorithm uses feedback from sensors embedded in the primary mirror. Control algorithms using both strain gages and temperature sensors are developed and compared to determine which sensor type results in better performance. The shape control algorithm with temperature sensors is analyzed using the parametric rib-stiffened mirror model to determine what geometries are best for shape control. The dynamic analysis is combined with the thermal control analysis in order to determine what mirror geometries will be favorable for both of these problems.
by Elizabeth Jordan.
S.M.
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Sleem, Lama. "Design and implementation of lightweight and secure cryptographic algorithms for embedded devices." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD018.
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Nous vivons actuellement dans une ère avec sans cesse de nouveaux appareils technologiques (smartphone, réseaux de capteurs sans fil, aux caméras haute résolution, etc). En partant des médias sociaux, en passant par des caméras de surveillance très puissantes, et sans oublier la surveillance de la santé en temps réel, on constate qu'une grande quantité de données est stockée dans le cloud et les serveurs. Cela représente un grand défi de stockage et de transmission, en particulier dans les plates-formes aux ressources limitées qui sont caractérisées par : (a) des capacités de calcul limitées, (b) une source d'énergie limitées et (c) des infrastructures ouvertes qui transmettent des données sur des réseaux sans fil peu fiables. Dans cette thèse, nous nous concentrons sur l'amélioration de la sécurité des contenus multimédia transmis sur des plates-formes à capacité de calcul limitée, tout en préservant un niveau de sécurité élevé. Dans la première partie, nous avons étudié les réseaux ad hoc véhiculaire. Nous avons proposé un état de l'art qui permet de résumer la plupart des travaux récents et d'explorer presque tous les aspects de ce domaine en illustrant les différents aspects que possède cette plateforme. Ensuite, afin de proposer une nouvelle solution de sécurité et de valider sa robustesse et le niveau de caractère aléatoire d'une image chiffrée, nous avons proposé un test simple et efficace. Celui-ci est basé sur des outils pour tester statistiquement le caractère aléatoire de nombres pseudo aléatoires, TestU01 et Practrand. Après avoir effectué ces tests sur des algorithmes de chiffrement bien connus, certaines failles ont été exposées et une nouvelle proposition visant à améliorer le système de chiffrement ultra-léger Speck est proposée. La principale contribution de ce travail est d'obtenir une meilleure version par rapport à Speck. Dans cette nouvelle proposition, appelée Speck-R, nous utilisons seulement 7 itérations contrairement à Speck qui en utilise 26 et nous réduisons le temps d'exécution d'au moins 50%. Tout d'abord, nous validons que Speck-R répond aux tests de statistiques pour mesurer l'aléatoire, proposés précédemment. De plus, nous avons rajouté un système de clé dynamique qui procure plus de sécurité contre les attaques liées à la clé. Speck-R a été implémenté sur différentes cartes de type arduino et dans tous les cas, Speck-R était plus rapide que Speck. Ensuite, afin de prouver que ce chiffrement peut être utilisé pour sécuriser les images, en particulier dans les réseaux VANETS/IoV, plusieurs tests ont été effectués et les résultats montrent que Speck-R possède effectivement le haut niveau de sécurité souhaité. Des expérimentations valident notre proposition du point de vue de la sécurité et de la performance et démontrent la robustesse du système proposé face aux types d'attaques les plus connusLiving in an era where new devices are astonishing considering their high capabilities, new visions and terms have emerged. Moving to smart phones, Wireless Sensor Networks, high-resolution cameras, pads and much more, has mandated the need to rethink the technological strategy that is used today. Starting from social media, where apparently everything is being exposed, moving to highly powerful surveillance cameras, in addition to real time health monitoring, it can be seen that a high amount of data is being stored in the Cloud and servers. This introduced a great challenge for their storage and transmission especially in the limited resourced platforms that are characterized by: (a) limited computing capabilities, (b) limited energy and source of power and (c) open infrastructures that transmit data over wireless unreliable networks. One of the extensively studied platforms is the Vehicular Ad-hoc Networks which tends to have many limitations concerning the security field. In this dissertation, we focus on improving the security of transmitted multimedia contents in different limited platforms, while preserving a high security level. Limitations of these platforms are taken into consideration while enhancing the execution time of the secure cipher. Additionally, if the proposed cipher is to be used for images, the intrinsic voluminous and complex nature of the managed images is also taken into account. In the first part, we surveyed one of the limited platforms that is interesting for many researchers, which is the Vehicular Ad-hoc Networks. In order to pave the way for researchers to find new efficient security solutions, it is important to have one reference that can sum most of the recent works. It almost investigates every aspect in this field shedding the light over different aspects this platform possesses. Then, in order to propose any new security solution and validate its robustness and the level of randomness of the ciphered image, a simple and efficient test is proposed. This test proposes using the randomness tools, TestU01 and Practrand, in order to assure a high level of randomness. After running these tests on well known ciphers, some flaws were exposed. Proceeding to the next part, a novel proposal for enhancing the well-known ultra lightweight cipher scheme, Speck, is proposed. The main contribution of this work is to obtain a better version compared to Speck. In this proposal, 26 rounds in Speck were reduced to 7 rounds in Speck-R while enhancing the execution time by at least 50%. First, we validate that Speck-R meets the randomness tests that are previously proposed. Additionally, a dynamic substitution layer adds more security against key related attacks and highly fortifies the cipher. Speck-R was implemented on different limited arduino chips and in all cases, Speck-R was ahead of Speck. Then, in order to prove that this cipher can be used for securing images, especially in VANETS/IoV, where images can be extensively re/transmitted, several tests were exerted and results showed that Speck-R indeed possesses the high level of security desired in any trusted cipher. Extensive experiments validate our proposal from both security and performance point of views and demonstrate the robustness of the proposed scheme against the most-known types of attacks
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Yao, Jerry Wei-Hua. "IDK : an Interaction Development Kit to design interactions for lightweight autonomous vehicles." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/127725.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2019Cataloged from PDF of thesis.
Includes bibliographical references (pages 78-80).
Various studies have demonstrated that privately owned cars will become significantly less prevalent in the city in the next 10 to 15 years. Other efficient alternatives for mobility platforms within the city are in demand around the world. One example is the emergence of the PEV (Persuasive Electric Vehicle), an agile autonomous bike-sharing platform (M Lin, 2015). Based on this trend, it is reasonable to anticipate that increasingly more mobility systems of different forms will emerge in urban areas in the future. These new mobility systems might not necessarily be similar to cars; they may instead be a new class of social robot that could blend into the city more seamlessly. Moreover, when there is no longer a driver within each vehicle, designing human-machine interface (HMI) that is simple for users to process will be more important than ever.
For example, if a pedestrian encounters a lightweight autonomous vehicle for which it is apparent that no one is in the vehicle, how can the pedestrian understand the intention of the vehicle? And how can we, as designers, make this more intuitive and seamless? This thesis presents IDK, which is an Interaction Development Kit equipped with essential tools to help facilitate the design and prototyping process. IDK could be physically installed in PEVs, thereby enabling designers and developers to prototype human-machine interactions in a rapid and intuitive manner. This thesis also identifies multiple situations that a lightweight autonomous vehicle may encounter while navigating through streets and proposes a range of interactions that can tackle these problems. All prototypes from this thesis are based on the latest version of the PEV as an interactive platform.
The proposed interactions are evaluated through outdoor testing as well as indoor exhibitions to determine how people respond to these new norms of communication. My hope is that the results of this thesis will provide useful insights for designers and developers who seek to develop interactions that allow humans to seamlessly interact with lightweight autonomous vehicles.
by Jerry Wei-Hua Yao.
S.M.
S.M. Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences
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Ulbricht, Andreas, Maik Gude, Daniel Barfuß, Michael Birke, Andree Schwaar, and Andrzej Czulak. "Potential and application fields of lightweight hydraulic components in multi-material design." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200294.
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Hydraulic systems are used in many fields of applications for different functions like energy storage in hybrid systems. Generally the mass of hydraulic systems plays a key role especially for mobile hydraulics (construction machines, trucks, cars) and hydraulic aircraft systems. The main product properties like energy efficiency or payload can be improved by reducing the mass. In this connection carbon fiber reinforced plastics (CFRP) with their superior specific strength and stiffness open up new chances to acquire new lightweight potentials compared to metallic components. However, complex quality control and failure identification slow down the substitution of metals by fiber-reinforced plastics (FRP). But the lower manufacturing temperatures of FRP compared to metals allow the integration of sensors within FRP-components. These sensors then can be advantageously used for many functions like quality control during the manufacturing process or structural health monitoring (SHM) for failure detection during their life cycle. Thus, lightweight hydraulic components made of composite materials as well as sensor integration in composite components are a main fields of research and development at the Institute of Lightweight Engineering and Polymer Technology (ILK) of the TU Dresden as well as at the Leichtbau-Zentrum Sachsen GmbH (LZS).
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Tinashe, Kurehwaseka. "Lightweight Remote Collaboration System based on WebRTC : Improving Remote Collaboration Flexibility." Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12816.
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Context. Introduction of efficient multimedia technologies combined with the spreading of high-speed internet connection all over the world has led to the continuous increase in demand of multimedia services, particularly video and audio. One of the major demands are flexible, interoperable and cost-effective lightweight remote collaboration systems in companies. Web Real Time Communication (WebRTC) is an emerging peer to peer technology that is promising to be the solution to many digital real-time communication challenges. With its fantastic one-to-one communication capabilities, WebRTC supports fast and smooth audio calls, video calls, conferencing, data (media file, document and screen) sharing, gaming and all sorts of messages exchange, all being done straight out of the browser. However, as shown by investigations and interviews supported by Ericsson AB and Semcon AB as party of the MERCO (Mediated Effective Remote Collaboration) international project, many corporate use cases of remote collaboration involve applications beyond the conventional one to one communication. Present videoconferencing systems (telepresence) limits the collaboration flexibility due to their lack of the ability to adapt to system resource usage, hence tend to be too heavy for less powerful devices (laptops, tablets, phones). Moreover, their installation and maintenance costs are too expensive for small companies. Therefore, new flexible, lightweight and less expensive solutions for remote collaboration need to be developed. Objectives. The main objective of this thesis is to identify technical solutions to address the challenges of resource usage flexibility in WebRTC multi-party remote collaboration systems. Despite concurrent developments of both commercial and free solutions that provide multi-party videoconferencing services using WebRTC, present solutions such as the conventional Multipoint Control Unit (MCU), Selective Forwarding Unit (SFU) and Fully Meshed architectures suffers from issues of excessive resource usage and cannot deliver the acceptable quality of experience in different use cases, particularly the mobile environment. The aim of this thesis is to investigate lightweight technical solutions that can be used to improve the system resource usage in WebRTC multiparty conferencing systems. Through understanding the architectural designs, benchmarking the performance of various technologies used in WebRTC and selecting the most suitable techniques a prototype is developed as a proof of concept. Methods. The first part of the thesis is dedicated to comprehensive study of fundamentals, background information and related works on WebRTC. This gives knowledge of technologies, techniques and performance evaluation metrics which help in making appropriate technical decisions during the experimental development of WebRTC solutions. The second part of the thesis is dedicated to experimental investigation in which two WebRTC signaling technologies (XSockets and NodeJs) are evaluated based on call setup time in WebRTC group call. Two lightweight technical solutions for improving resource usage flexibility (Switching video quality based on speech and using emotions and gestures instead of video) are evaluated based on system resources (CPU, memory, disk and network) and user experience. Results. Based on call setup time of WebRTC multi-party calls, the experimental results indicates that XSockets is a better signaling technology than NodeJs. The two proposed lightweight solutions have shown a remarkable improvement based on systems resource usage. A 15% reduction of CPU usage is observed when using speech controlled video quality switching and further 10% reduction is observed when video is replaced by emotions and gestures. Conclusions. Despite the minimal resource usage achieved by using emotions technique, this solution has usability issues as it cannot detect emotions in poor lighting environment. Consequently, the solution of switching video quality based on speech is chosen for further implementation. Though, this technique can be further improved through using machine learning techniques, the current implementation can significantly reduce the amount CPU, memory, disk and network usage to allow up to 6 participants to join a single conference call while maintain acceptable quality of experience.
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Tinker, John Andrew. "Development of an Ultra-Lightweight Buckling-Restrained Brace Using Analytical and Numerical Methods." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/447.
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An ultra-lightweight buckling-restrained brace (ULWBRB) is developed using a highly ductile aluminum core and FRP restrainer. Utilization of lightweight materials results in a BRB that is 25% the weight of traditional mortar-filled tube varieties allowing easy installation in small to medium sized buildings requiring seismic retrofit without the need for heavy equipment. Construction utilizes commonly stocked materials able to be customized for required strength, drift, and geometry limitations. Analytical single degree of freedom (SDOF) and Euler buckling models are compared with published equations to determine the required restrainer stiffness (RRS). SDOF models yield RRS values 200% higher than the Euler model. Applied end moments due to frame deformation are incorporated into a modified design method that gives RRS values 50% higher than Euler model without eccentricity. RRS is provided using a bundled and wrapped FRP tube configuration using a developed shear flow method considering composite action. Uniaxial low-cycle fatigue (LCF) testing of a 6061-T6 candidate alloy provides data for a constitutive model using combined kinematic-isotropic hardening. LCF testing of round short gage coupons indicates the candidate alloy is capable of stable cycling to 2%, 3%, and 4% total strain with excellent ductility. Early fracture of specimens at 24, 18, and 11 cycles, respectively, also indicates that other candidate alloys should be examined for improved fatigue life. However, inconsistency is noted between similar tests of 6061-T6 that were able to achieve up to 76 cycles at 2.5% total strain. ULWBRB FEA models loaded monotonically consistently give higher RRS values as compared to the analytical methods. This is due to assignment of initial imperfections, longer more realistic unbraced length, higher axial loads achieved through the post-yield region, and plastic hinging potential. Cyclic simulations of braces with the same RRS values are also able to achieve reliable and stable hysteretic behavior through 21 cycles. If a less stiff restrainer is used, cumulative energy dissipation potential is reduced considerably due to pinched hysteresis loops and strain ratcheting. Applied end moments are found to have a linear effect on the RRS that can be modeled by superposition of the buckling effect plus end moment.
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Scheidt, Matthew. "Lightweight Aluminum Structures with EmbeddedReinforcement Fibers via Ultrasonic Additive Manufacturing." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469112453.
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