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Dissertations / Theses on the topic 'Monocoque'
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Lizotte, Patrick L. "Stress analysis and fabrication of composite monocoque bicycle frames." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24064.
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An analytical and experimental investigation was conducted to study the design and fabrication of carbon fiber track bicycle frames. A finite element software was used for the geometry development, laminate configuration, and for predicting failure using the maximum stress criteria. A load case and boundary conditions simulating actual riding conditions were developed. The stresses in each of the composite layers were found to be lower than the allowable stresses because of a properly designed geometry and laminate. Two composite frames were fabricated using the hand lay-up technique, using unidirectional and woven carbon fiber pre-preg material over an internal foam core. Using static testing techniques and comparisons with traditional tubular frames, the carbon fiber prototypes were shown to be better in all rigidity aspects. Combining the experimental and theoretical results, a good understanding of the critical problems related to composite monocoque bicycle frame design was obtained.
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Humphreys, Matthew. "Development and Structural Investigation of Monocoque Fibre Composite Trusses." Queensland University of Technology, 2003. http://eprints.qut.edu.au/15898/.
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Fibre composite materials are gaining recognition in civil engineering applications as a viable alternative to traditional materials. Their migration from customary automotive, marine, aerospace and military industries into civil engineering has continued to gain momentum over the last three decades as new civil engineering applications develop. The use of fibre composite materials in civil engineering has now evolved from non-structural applications, such as handrails and cladding, into primary structural applications such as building frames, bridge decks and concrete reinforcement. However, there are issues which are slowing the use of fibre composite materials into civil engineering. Issues include high costs, difficulties in realising potential benefits, general lack of civil engineers' familiarity with the material and relatively little standardisation in the composites industry. For composites to truly offer a viable alternative to traditional construction materials in the civil engineering marketplace, it is essential that these issues be addressed. It is proposed that this situation could be improved by demonstrating that potential benefits offered by composites can be achieved with familiar civil engineering forms. These forms must be well suited to fibre composite materials and be able to produce safe and predictable civil engineering structures with existing structural engineering methods. Of the numerous structural forms currently being investigated for civil engineering applications, the truss form appears particularly well suited to fibre composites. The truss is a familiar structural engineering form which possesses certain characteristics that make it well suited to fibre composite materials. In this research a novel monocoque fibre composite truss concept was developed into a working structure and investigated using analytical and experimental methods. To the best of the author's knowledge the research presented in this thesis represents the first doctoral research into a structure of this type. This thesis therefore presents the details of the development of the monocoque fibre composite (MFC) truss concept into a working structure. The developed MFC truss was used as the basis for a detailed investigation of the structural behaviour of the MFC truss elements and the truss as a whole. The static structural behaviour of the principal MFC truss elements (tension members, compression members and joints) was investigated experimentally and analytically. Physical testing required the design and fabrication of a number of novel test rigs. Well established engineering principles were used along with complex finite element models to predict the behaviour of the tested truss elements and trusses. Results of the theoretical analysis were compared with experimental results to determine how accurately their static structural behaviour could be predicted. It was found that the static structural behaviour of all three principal truss elements could be accurately predicted with existing engineering methods and finite element analysis. The knowledge gained from the investigation of the principal truss elements was then used in an investigation of the structural behaviour of the MFC truss. Three full-scale MFC trusses were fabricated in the form of conventional Pratt, Howe and Warren trusses and tested to destruction. The investigation included detailed finite element modelling of the full-scale trusses and the results were compared to the full-scale test results. Results of the investigation demonstrated that the familiar Pratt, Howe and Warren truss forms could be successfully manufactured with locally available fibre composite materials and existing manufacturing technology. The static structural behaviour of these fibre composite truss forms was accurately predicted with well established engineering principles and finite element analysis. A successful marriage between fibre composite materials and a civil engineering structure has been achieved. Monocoque fibre composite trusses have been developed in the familiar Pratt, Howe and Warren truss forms. These structures possess characteristics that make them well suited to applications as primary load bearing structures.
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Santos, Fábio Henrique Massuia de Souza. "Modelagem computacional para análise de tensões e deslocamentos em fuselagem semi-monocoque." Instituto Tecnológico de Aeronáutica, 2004. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2905.
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Este trabalho apresenta a análise de tensões e deslocamentos de uma fuselagem semi-monocoque através do método dos elementos finitos. Os diversos modelos utilizados nas análises possuem variações a partir de dois modelos básicos. O primeiro modelo considera o modelamento de cavernas e reforçadores como elementos de barra. O segundo modelo considera que somente os reforçadores devem ser modelados com elementos de barra; as cavernas, neste modelo, são modeladas com elementos de placa. As variações consideradas são: modelamento e não modelamento dos shear clips, presença e ausência de offsets nos reforçares e discretização da malha (malhas mais grosseira e malhas mais refinidas). Os resultados obtidos mostram que a quantidade e qualidade da malha influenciam muito mais os resultados do que presença ou não de offsets. Modelos com mesma malha, porém com diferença entre os offsets, possuem resultados muito próximos. A modelagem ou não dos shear clips influência na rigidez da estrutura e conseqüentemente deve ser modelado para melhor representar a estrutura real.
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Rich, Jonathan E. "Design Optimization Procedure for Monocoque Composite Cylinder Structures Using Response Surface Techniques." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35512.
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An optimization strategy for the design of composite shells is investigated. This study differs from previous work in that an advanced analysis package is utilized to provide buckling information on potential designs. The Structural Analysis of General Shells (STAGS) finite element code is used to provide linear buckling calculations for a minimum buckling load constraint. A response surface, spanning the design space, is generated from a set of design points and corresponding buckling load data. This response surface is incorporated into a genetic algorithm for optimization of composite cylinders. Laminate designs are limited to those that are balanced and symmetric. Three load cases and four different variable formulations are examined. In the first approach, designs are limited to those whose normalized in-plane and out-of-plane stiffness parameters would be feasible with laminates consisting of two independent fiber orientation angles. The second approach increases the design space to include those that are bordered by those in the first approach. The third and fourth approaches utilize stacking sequence designs for optimization, with continuous and discrete fiber orientation angle variation, respectively. For each load case and different variable formulation, additional runs are made to account for inaccuracies inherent in the response surface model. This study concluded that this strategy was effective at reducing the computational cost of optimizing the composite cylinders.Master of Science
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Paulin, Julio Cezar. "Dimensionamento preliminar de uma seção de fuselagem semi-monocoque de uma aeronave de passageiros." Instituto Tecnológico de Aeronáutica, 2008. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1173.
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Um método de pré-dimensionamento da estrutura da fuselagem de uma aeronave foi desenvolvido nesse trabalho com o objetivo de possibilitar ao engenheiro de estruturas o cálculo rápido dos esforços primários e secundários, bem como das margens de segurança dessa estrutura. Para tanto, as teorias de cálculo desse tipo de estrutura foram implementadas em uma planilha de forma a permitir que o engenheiro mude com facilidade os parâmetros de projeto, podendo assim buscar uma solução mais eficiente. Neste trabalho são discutidas também as conseqüências de não se considerar as reduções das áreas efetivas do revestimento, devido à flambagem dos mesmos, no cálculo da área total resistente à compressão axial.
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Castillo, Henry A. "Optimum design of isotropic monocoque and ring-stiffened circular cylindrical shells subject to external hydrostatic pressure." Thesis, Monterey, California : Naval Postgraduate School, 1992. http://handle.dtic.mil/100.2/ADA257864.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 1992.Thesis Advisor: Salinas, David. Description based on title screen as viewed on April 16, 2009. Includes bibliographical references (p. 124). Also available in print.
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Mello, Pedro Paulo Serrajordia Rocha de. "Análise da influência dos esforços primários em fuselagem semi-monocoque nas tensões de da tração diagonal." Instituto Tecnológico de Aeronáutica, 2004. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=611.
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A determinação dos esforços primários via NASTRAN, ao contrário do que ocorre ao se utilizar a teoria do engenheiro que faz uso extensivo de larguras efetivas de chapa, baseia-se na hipótese de que os painéis não flambam. A redistribuição das tensões ocorre apenas levando-se em conta os efeitos da tração diagonal, enquanto a flambagem dos painéis não é levada em conta neste estudo. Sabendo-se que ao não considerar a flambagem, erros podem ser cometidos, este trabalho realiza uma comparação entre duas análises da estrutura primária: análise usando NASTRAN, levando-se em conta a redistribuição de tensão devido à tração diagonal - sem considerar a flambagem dos painéis; e análise da teoria do engenheiro considerando a flambagem dos painéis, através do uso de larguras e áreas efetivas dos painéis flambados, também se levando em conta a redistribuição de tensões devido à tração diagonal. Aqui se apresenta a questão de como devem ser utilizados os resultados obtidos através de uma análise de uma fuselagem semi-monocoque pelo NASTRAN, face ao fato de que existe a possibilidade real de flambagem de chapas dessa estrutura.
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Dababneh, Odeh. "Design, Analysis And Optimization Of Thin Walled Semi-monocoque Wing Structures Using Different Structural Idealizations In The Preliminary Design Phase." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613759/index.pdf.
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This thesis gives a comprehensive study on the effect of using different structural idealizations on the design, analysis and optimization of thin walled semi-monocoque wing structures in the preliminary design phase. In the design part, wing structures are designed by employing two different structural idealizations that are typically used in the preliminary design phase. In the structural analysis part, finite element analysis of one of the designed wing configurations is performed using six different one and two dimensional element pairs which are typically used to model the sub-elements of semi-monocoque wing structures. The effect of using different finite element types on the analysis results of the wing structure is investigated. During the analysis study, depending on the mesh size used, conclusions are also inferred with regard to the deficiency of certain element types in handling the true external load acting on the wing structure. Finally in the optimization part, wing structure is optimized for minimum weight by using finite element models which have the same six different element pairs used in the analysis phase. The effect of using different one and two dimensional element pairs on the final optimized
configurations of the wing structure is investigated, and conclusions are inferred with regard to the sensitivity of the optimized wing configurations with respect to the choice of different element types in the finite element model. Final optimized wing structure configurations are also compared with the simplified method based designs which are also optimized iteratively.
Based on the results presented in the thesis, it is concluded that with the simplified methods, preliminary sizing of the wing structures can be performed with enough confidence, as long as the simplified method based designs are also optimized. Results of the simplified method of analysis showed that simplified method is applicable to be used as an analysis tool in performing the preliminary sizing of the wing structure before moving on to more refined finite element based analysis.
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Mende, Milan. "Konstrukční návrh kompozitního chassis Formule Student." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-449785.
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The Master’s thesis deals with the design and production of a composite chassis of the new formula Dragon X. The carbon prepreg used for manufacturing of the monocoque was to be operated at high temperatures. Therefore, this thesis deals with the application of composites structures in the high temperature environment. The thesis addresses the torsional stiffness problematics and it was not only physically tested, but also simulated by FEM analysis and the results were compared.
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Ricardo, Vagner Proença. "Projeto comparativo da fuselagem central de uma aeronave em material compósito e alumínio." Instituto Tecnológico de Aeronáutica, 2004. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=675.
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Esse trabalho apresenta uma metodologia para seleção da melhor concepção na fabricação da fuselagem central de uma aeronave executiva de seis ocupantes. Para isso, são estudadas três possibilidades: construção semi-monocoque em alumínio; materiais compósitos produzidos por Laminação por Controle Numérico e materiais compósitos produzidos por Hand Lay-up. A metodologia permite uma análise quantitativa das concepções, mesmo em fases iniciais do projeto, o que contribui para a seleção das melhores opções de concepções logo no início da análise. A partir deste estudo, ée possível observar que o projeto em Laminação por Controle Numérico ée mais adequado economicamente na fabricação da fuselagem em material compósito, devido a menores custos com matéria-prima e com mão-de-obra. Dessa maneira, o estudo prossegue com as duas concepções (material compósito fabricado por Laminação por Controle Numérico e estrutura semi-monocoque em alumínio). ÉE realizado o pré-dimensionamento das duas soluções, e em seguida estima-se o peso e o custo de fabricação das mesmas. A análise comparativa entre as soluções mostra que a concepção em material compósito apresenta uma diminuição de peso considerável acompanhada de ligeira diminuição de custo, o que permite concluir que ela se apresenta como uma alternativa técnica e economicamente viável e interessante do ponto de vista de ganho em desempenho da aeronave.
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Čížková, Markéta. "Analýza poškození dopravního letounu při teroristickém útoku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443754.
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In its theoretical part, the diploma thesis deals with the reasons leading to terrorist attacks and a brief list of some attacks on aircraft. It also focuses on the aircraft as the target of a terrorist attack, especially the aircraft kite as the major researched part. The conclusion of the theoretical part summarizes a list of types of aircraft fuselage structures in respect of design solutions for load transfer. The practical part determines the extent of damage caused by a missile with a fragmentation warhead. This scope is then applied to the illustrative case. In the following chapters, the calculation of the critical force of a panel loaded with pressure depends on the different nature and extent of damage. Then the work highlights the evaluation of the obtained results, which are also summarized in the conclusions of the work.
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Rissato, Flavio Pereira. "Análise da tração diagonal em uma fuselagem considerando-se a energia de deformação do sistema." Instituto Tecnológico de Aeronáutica, 2004. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=640.
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O objetivo deste trabalho ée analisar a seção transversal de uma fuselagem semi-monocoque de uma aeronave corporativa, levando-se em consideração os efeitos da tração diagonal. As ferramentas de análise são programas desenvolvidos em linguagem Fortran, onde um dos programas ée baseado no método apresentado por Kuhn em seus estudos para o cálculo da tração diagonal, amplamente aplicado na indústria aeronáutica, e o outro baseado na energia de deformação de um sistema estrutural composto por reforçadores, cavernas e revestimento, sem levar em consideração os efeitos dos carregamentos secundários e do termo adicional proposto por Kuhn em sua teoria para a deformação da caverna, termo este que ée justificado por Kuhn devido à tendência da alma curva ficar plana entre cavernas quando a alma está sob um estado de tração diagonal bem desenvolvido. Os dois métodos são comparados e os resultados e conclusões são apresentados.
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Zamazal, Jakub. "Návrh rekonstrukce střední části trupu letounu Z 143 náhradou za poloskořepinu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318137.
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The thesis is focused on reconstruction of middle part of fuselage Z 143 aircraft from truss frame to semi-monocoque frame. In the thesis there is a conceptual design of semi-monocoque middle part of fuselage. The spars of centre wing section are strength controlled. In thesis there is weight analysis according to use the semi-monocoque middle part of fuselage. In second half of the thesis there is a study of retractable landing gear. The thesis shows weight savings according to use a semi-monocoque frame. The thesis also shows that semi-monocoque frame allows other option to upgrade Z 143 aircraft. This thesis can serve as a feasibility study of the reconstruction of the middle part of the fuselage Z 143 aircraft.
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Děrda, Martin. "Návrh rámu vozidla Formule Student." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318534.
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This diploma thesis focuses on proposing construction and manufacture plans of a hybrid frame chassis consisting of a tubular space frame and a monocoque made of composite materials. Next, it discusses the simulation of the chassis via FEM analysis and also measuring of its torsional stiffness. In the final part of the thesis, the frame is compared to its older predecessor, which is made solely of a tubular space frame, and its advantages and disadvantages are evaluated.
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Žídek, Tomáš. "Návrh monokoku formulového vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231441.
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The diploma thesis describes the design of a carbon fiber monocoque Formula Student car according to current rules. The first part is focused on construction solutions of frames used in Formula Student cars. Following is a summary of the important rules for constructing composite monocoque. Subsequently are described composite materials and their properties. The main part of the thesis deals with the structural design of the CAD program and a computational model to simulate the load case in FEM program. The obtained results from the analysis of the monocoque are compared with the values allowed by the rules of Formula Student. In conclusion of this thesis is evaluated the proposed composite monocoque.
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Žídek, Tomáš. "Aplikace sendvičové konstrukce na formulový vůz." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254214.
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The master thesis describes application of a sandwich construction for Formula Student car. It will replace the current tubular space frame according to FSAE rules. The introduction is focused on the information of international Formula Student competition, including TU Brno Racing Team. Then there are important rules for the construction of frames and composite monocoques. For the selected production technology are found strength properties of face sheets made of carbon and hybrid fibres. Another part of thesis deals with the design of the sandwich panel using analytical calculation to determine the bending stiffness. On the basis of these proposals are made three-point bending and shear tests. Using of FEM simulation is detected torsional stiffness of the tubular space frame and the monocoque concept from the proposed sandwich panels. The conclusion is devoted to a summary of the important information and possible monocoque manufacturing process.
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Truong, Thi Hanh. "Le dan bâu (monocorde calebasse vietnamien). Étude organologique et ethnomusicologique." Thesis, Paris 4, 2009. http://www.theses.fr/2009PA040267.
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Le dan bâu est un monocorde à tension variable spécifiquement vietnamien. Il est cité par les chroniques chinoises du Xe siècle parmi les instruments du Funan, du Champâ et du pays de Pyû, soit l’Indochine. Les sources vietnamiennes les plus anciennes remontent à 1777 (Lê Qui Dôn), suivies par les récits, dessins, croquis et photographies des voyageurs, explorateurs puis ethnologues. Il apparaît que l’instrument au début du XXe siècle était l’apanage des mendiants aveugles. Au cours du siècle, il est cependant devenu un des emblèmes de la musique vietnamienne, objet d’améliorations dans la facture, et surtout d’une modification du jeu instrumental avec l’usage systématique du jeu en harmoniques qui lui permet de jouer tous les modes et toutes les nuances, et des ornements aussi subtils que variés. Actuellement, l’incorporation à l’ensemble caisse-corde-résonateur-levier d’une chaîne microphone-amplificateur-haut-parleur lui permet d’être entendu parmi d’autres instruments et dans la situation du concert. Il présente ainsi le cas d’un instrument resté traditionnel et vietnamien et ayant totalement intégré la modernité.L’étude organologique, comprenant description et facture, se prolonge avec un aperçu général qui situe le dan bâu au sein des monocordes asiatiques. L’étude musicologique présente les modes de jeu, le système modal des pièces de son vaste répertoire ; elle est complétée par un description des techniques de jeu et une étude d’acoustique musicale. L’enseignement au sein des conservatoires est exposé avec la publication d’un manuscrit inédit d’un maître. Le travail s’ouvre en fin sur une proposition de l’utilisation du dan bâu dans le cadre de la musicothérapieThe dan bâu is a variable tension, monochord chordophone, specific to Vietnam. Chinese historical records from the Xth Century describe the baoqin among instruments from Funan, Champâ, and Pyû, which means present days Indochina, while Vietnamese records only start from 1777 (Lê Qui Dôn), followed by descriptions, sketches, and photographs by travellers and ethnographers. It appears that at the turn of XXth century the instrument was played by blind street musicians. During this century, it has become one of the characteristic sounds of Vietnamese musical culture, through modifications in its building, the materials used, and in its playing, which now incorporates the systematic use of controlled harmonics. The addition of an electro acoustic chain of amplification has been an important contribution to its integration as a concert instrument. It can be taken as a perfect example of a traditional instrument integrated into modernity.The organological study, including a description of the instrument, its variants and techniques of building, opens to an overview of the various monochords in Asia. The musicological study presents the modal system with its idiomatic ornaments, the large repertoire. It is completed by a study of the playing techniques and an acoustic analysis. The teaching of the instrument and its music inside of the conservatories is exposed through the publication of a manuscript by a Master. The work ends with a proposition about the use of the dan bâu in the context of music therapy
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SIMONIN, ALAIN. "Etude d'un detecteur permettant la mesure en monocoup de la forme temporelle d'une impulsion de lumiere incoherente de largueur (80 a 150 ps) issue du collisionneur lep par effet synchrotron." Paris 11, 1991. http://www.theses.fr/1991PA112300.
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Une impulsion de lumiere tres breve (80 ps) extraite du collisionneur lep par effet synchrotron, est injectee dans un systeme constitue d'anneaux de fibres optiques monomodes, relies par des coupleurs optiques, afin de realiser un stockage de photons durant 22 micro-secondes. Ce systeme agit comme un generateur periodique (periode: 12 ns) de photons uniques, durant les 22 micro-secondes. On realise l'histogramme du temps de vol de chaque photon par rapport a une horloge externe, au moyen d'un convertisseur temps-amplitude. La distribution de ces temps de vol, est proportionnelle a la forme temporelle de l'impulsion. La detection de photons uniques, s'effectue au moyen d'une photo-diode a avalanche, polarisee au-dela de sa tension de claquage durant 3 nano-secondes. L'arrivee du photon provoque une avalanche se traduisant par une impulsion electrique dont la charge est proportionnelle au temps de vol du photon. Un integrateur convertit en sortie cette charge en tension qui sera ensuite numerisee. La photo-diode doit etre en mesure de fonctionner toutes les 12 ns, ce qui pose actuellement des problemes, pour cause d'evacuation trop lente des porteurs de charge. Des simulations par ordinateur sont realisees pour calculer les parametres optiques des systemes d'anneaux. Les pertes optiques de chaque anneau doivent etre faibles, pour que le nombre de photons uniques en sortie soit suffisant afin d'avoir une bonne statistique pour composer l'histogramme. Durant la propagation, l'impulsion lumineuse subit une distorsion, induite par la dispersion chromatique, et il est necessaire de limiter l'intervalle spectral. Le banc optique est assemble, mais le probleme de la photo-diode est toujours a l'etude
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Loriot, Vincent. "Alignement moléculaire par impulsions laser ultrabrèves : Mesures & Applications." Phd thesis, Université de Bourgogne, 2009. http://tel.archives-ouvertes.fr/tel-00660050.
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L'interaction entre un échantillon moléculaire gazeux et une impulsion laser ultra-brève intense conduit, après le passage de l'impulsion, à des réalignements transitoires et périodiques des molécules. Cette thèse se rapporte à la mesure et aux applications liées à cet effet. Le degré d'alignement moléculaire est déterminé à travers la variation d'indice de réfraction induite par le réarrangement des dipôles moléculaires. Une technique d'imagerie bidimensionnelle permettant de mesurer sur une base monocoup l'alignement des molécules est reportée dans ce manuscrit. L'alignement est ensuite utilisé comme un outil de mesure pour évaluer des quantités physiques, difficilement accessibles par d'autres méthodes. La "technique de défocalisation croisée" a été tout d'abord employée pour mesurer les probabilités d'ionisation de gaz atomiques et moléculaires en régime femtoseconde. La "technique de polarisation 1D" a été ensuite appliquée pour obtenir une mesure de l'indice Kerr électronique calibré à travers l'alignement moléculaire. Il a été trouvé que l'effet Kerr électronique produit une variation d'indice qui change de signe aux alentours des 30 TW.cm-2 pour les principaux gaz qui constituent l'atmosphère. Cet effet a été interprété de manière phénoménologique par des termes Kerr d'ordres supérieurs (de n4 à n10). L'impact important de ces résultats sur la compréhension du mécanisme de filamentation est discuté.
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Oliveira, Pedro. "Ultrafast lasers in the femtosecond regime : generation, amplification and measurement." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00942477.
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Il est intuitif qu'avec de nouveaux outils, il devient possible d'explorer de nouveaux domaines de la physique. Les champs électromagnétiques ultra-rapides sont l'un de ces outils, ils permettent de sonder la matière à de nouvelles échelles de temps, à la fois pour développer de nouvelles applications et pour la recherche fondamentale. Néanmoins, ces champs constituent en eux-mêmes un phénomène méritant d'être analysé et étudié. Le travail présenté ici est divisé en deux parties, dont la première s'occupe de la génération et amplification de lasers ultracourtes. L'amplification paramétrique optique est discutée dans les différentes configurations, notamment dans le cas où le signal a une dérivé angulaire spectrale. On discute aussi deux oscillateurs à blocage de mode en phase. Ont présente aussi une nouvelle manière d'étudier son comportement en fonction des dimensions de la sous-cavité. La mesure de ces phénomènes représente également un défi en raison de l'échelle temporelle extrêmement réduite à laquelle ces phénomènes se produisent, échelle bien trop petite pour des méthodes de mesure traditionnelles. Dans ce manuscrit, nous avons abordé deux techniques de mesure bien connues: l'autocorrélation interférométrique (IAC) du second ordre et la corrélation croisée du 3ème ordre (TOCC). Avec l'IAC et une mesure de la puissance spectrale du champ, il est possible de reconstruire intégralement le champ électrique tandis que le TOCC associé à l'autocorrélation en intensité détermine le profil en intensité de manière unique, et ont présente des algorithmes que font la reconstruction avec un haut contraste. Nous avons par ailleurs étudié la réalisation d'une nouvelle configuration de corrélateur croisé monocoup.
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Gerbe, Vincent. "Etude et réalisation d'un dispositif optoélectronique d'échantillonnage pour l'analyse d'impulsions brèves et uniques." Grenoble 1, 1993. http://www.theses.fr/1993GRE10110.
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Le but de ce travail est l'etude et la realisation d'un dispositif optoelectronique d'echantillonnage large bande pour l'analyse d'impulsions uniques. Le premier chapitre presente l'etat de l'art et le principe des differents systemes optoelectroniques ultra-rapides existants. Le deuxieme chapitre comprend une succincte etude theorique et experimentale de la photoconduction rapide. Il presente les caracterisations de deux lots de materiaux photoconducteurs. Parmi ces caracterisations, des techniques de mesures subpicosecondes resolues en temps sont utilisees pour evaluer le temps de reponse de ces materiaux. Le troisieme chapitre introduit la theorie des lignes de transmission et presente les proprietes des lignes microrubans ainsi que les principales methodes numeriques utilisees pour leur analyse. Apres une rapide description des deux dispositifs concus pour les tests, les resultats de simulations et de caracterisations obtenus sur ces dispositifs sont presentes. La simulation est realisee a partir d'un modele 3d obtenu par discretisation spatiale et temporelle des equations de maxwell. Les caracterisations comportent des analyses transitoires (banc de reflectometrie) et harmoniques (analyseur vectoriel). Le quatrieme chapitre represente l'aboutissement de cette these puisqu'il decrit la realisation et les premiers tests effectues sur un systeme prototype d'echantillonnage optoelectronique monocoup
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Kamble, Meghana P. "Design and Analysis of a Composite Monocoque for Structural Performance : a Comprehensive Approach." Thesis, 2019. http://hdl.handle.net/1805/19975.
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Indiana University-Purdue University Indianapolis (IUPUI)Lately numerous studies have been performed to design composite monocoques with high strength and low weight for various student level racing contests. The objective of this paper is to develop an insightful methodology to design and de veloped a light-weight composite monocoque. The monocoque is designed to pass the mandatory static load tests laid down by the International Automobile Feder ation (FIA)Formula 3. These Formula 3 tests are considered the baseline of the desired structural integrity of the composite monocoque. The presented design tech nique emphasises on a monocoque developed for Sports Car Club of America (SCCA) races. The three standard load tests performed on the monocoque are Survival Cell Side test, Fuel Tank test and Side Intrusion test. A sandwich layup of bi-directional woven carbon/epoxy prepreg and aluminium honeycomb is optimized for minimum weight while predicting the unknown properties of layup and ensuring the mono coque doesnt experience failure. The approach intends to achieve minimum weight with high torsional rigidity and is capable of being used for the design and analysis of any kind of formula type composite monocoque.
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Figueira, Jorge Fernando Mimoso Pericao. "Análise e desenvolvimento de uma estrutura monocoque para um veiculo de elevada eficiência energética." Master's thesis, 2014. http://hdl.handle.net/10316/38844.
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Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.Esta dissertação tem como objetivo a análise e o desenvolvimento de uma estrutura monocoque de elevada eficiência estrutural (relação rigidez/massa) para incorporar o novo protótipo EV03i do projeto Eco Veículo, com vista a participar em competições de alto rendimento energético. Os objetivos deste estudo são a obtenção de uma estrutura monocoque, que irá equipar o EV03i, com valor de massa inferior ao atual XC20i, manter ou até aumentar a rigidez estrutural do veículo e manter ou aumentar a acessibilidade a qualquer parte do veículo, quer para a entrada e a saída do piloto, quer para operações de manutenção. Estes objetivos foram assim definidos de modo a que o EV03i atinja níveis de desempenho energético nunca antes atingidos pela equipa na Shell Eco-Marathon que é uma competição, a nível mundial, de veículos automóveis de elevada eficiência energética. Uma grande parte deste trabalho foi a fase inicial de seleção e estudo dos materiais a utilizar na construção da estrutura. A seleção e o estudo dos materiais ocuparam grande parte do tempo, pois tratava-se de materiais que nunca tinham sido combinados e por isso as suas propriedades mecânicas não eram conhecidas. Foi necessária a aprendizagem e compreensão do fenómeno dos materiais compósitos e materiais ortotrópicos, foram desenvolvidas folhas de cálculo de forma a obter, por via teórica, as propriedades desses materiais. Concluída esta fase, iniciou-se uma fase de testes com vista a adquirir contacto com o software que se iria utilizar para realizar as simulações pretendidas, ao mesmo tempo que se consolidavam os conhecimentos adquiridos sobre os materiais na fase anterior. A última fase consistiu na análise e simulação das estruturas que se tinham definido como objetivo. O resultado final foi uma estrutura monocoque, que cumpre todos os requisitos que lhe foram impostos, com uma massa de 5,23 kg.
The main objective of the work presented here is the research and development of a monocoque frame to embody the new EV03i prototype, aiming to take part in Shell Eco-Marathon high energy efficiency competition. The goals set here are to reduce weight, maintain or increase structural rigidity and maintain or increase cockpit space in the monocoque structure to be developed. The goals were set like so to achieve results never achieved before by the team in a Shell Eco-Marathon competition. The material study and selection was the major time consuming phase in this work as the materials selected were never tested before, therefore the respective mechanical properties were unknown. For this reason a learning stage was necessary to better understand composite and orthotropic materials, spreadsheets were created to obtain such properties with the knowledge gained in this phase. With this stage completed a test phase begun aiming to acquire software dexterity for better flowing computer simulations and at the same time consolidating the previously gained knowledge. The last stage consisted in research and simulation of the objective structures set earlier. The final result was a monocoque structure that fulfilled all the requirements and had a mass of only 5,23 kg.
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Aten, Daniel Warren Narayanan Ram Mohan Haupt Randy L. "A wideband, low profile, shorted top hat monocone antenna." 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4039/index.html.
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