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

Design And Manufacturing Of A Tactical Unmanned Air Vehicle

Senelt, Engin 01 October 2010 (has links) (PDF)
The aim of this study is to describe the conceptual design, performance analysis to validate the design and manufacturing steps of Middle East Technical University Tactical Unmanned Air Vehicle (METU TUAV). The system requirements are adopted from a market study and assumed as is. Utilizing competitor search and conceptual design methodology, the rough parameters of the aircraft are defined and a performance analysis is conducted to validate the requirements. After the design team is content that the design is meeting the requirements, material and production techniques are evaluated. The male and female molds of the aircraft are manufactured with glass fibre fabric and special mold resin. Using the female molds / with glass, carbon and aramid fibre materials and epoxy matrix / utilizing wet-layup and vacuum bagging techniques the METU TUAV is manufactured. Wing, tail and fuselage skins are manufactured first and the reinforcing structures are integrated and cured inside the skins. Then the skins are assembled and the separate components are obtained. The rear landing gear and tail booms are also manufactured from carbon fibre composites. The individual parts are assembled together in special alignment jigs and the METU TUAV is completed.
2

Mise en œuvre, instrumentation, validation et modélisation d’un système d’injection RTM pour la fabrication de structures composites de hautes performances / Implementation, instrumentation, validation and modeling of RTM injection system for the manufacturing of structural high performances composites

Waris, Marc 24 December 2012 (has links)
Les matériaux composites ont connu ces dernières années une forte croissance, croissance aujourd'hui renforcée par les nouvelles normes européenne visant à diminuer les émissions CO2 d'ici 2020. La réalisation de pièces complexes peut poser de nombreuses problématiques de fabrication comme la formation de zones sèches, ou la création de distorsions géométriques. Les origines de ces problématiques sont souvent liées à un manque de connaissance et de maîtrise des phases d'imprégnation des renforts et de cuisson du matériau. L'amélioration de la robustesse des procédés nécessite d'avoir une connaissance fine des phénomènes physiques qui ont lieu lors de l'élaboration. Dans cette perspective, les procédés d'élaboration de matériaux composites ont été étudiés à travers la mise en place d'un démonstrateur de laboratoire dans le cadre du projet LCM Smart. Ce pilote d'injection a permis de valider des solutions d'instrumentation, à partir de capteurs innovants (OFS) développés en partenariat avec le laboratoire d'optique Hubert Curien.L'application de cette instrumentation dans le cadre du suivi du procédé RTM a démontré les capacités des OFS pour le suivi des caractéristiques physiques de la pièce (le front d'écoulement, la température, les déformations résiduelles et le degré de cuisson). La comparaison des caractéristiques mesurées avec des simulations numériques effectuées en collaboration avec ESI, a montré une bonne corrélation.Enfin, l'instrumentation a permis de mettre en évidence l’intérêt d’un outillage composite en HexTool pour la réduction des contraintes résiduelles liées à l'interaction outil/pièce. / A significant growth in production and consumption of composite materials can be seen recently; growth reinforced by the new European standards, aimed at reducing CO2 emissions by the year 2020.The producing of complex parts can cause many difficulties for manufacturing because of their geometries and / or their constituents (using of various materials). For example, dry zones or geometric distortion formation. The origins of these difficulties are often related to a lack of knowledge and control of the reinforcement's impregnation phases and material curing.Improving the robustness of the processes demands a detailed knowledge of physical phenomena that occur during the producing. For this, we studied the composite materials production through the implementation of a laboratory demonstrator in the project LCM Smart. This pilot injection was used to validate instrumentation solutions, from innovative sensors (OFS) developed in partnership with the optical laboratory Hubert Curien. The application of this instrumentation in the context of RTM process monitoring in the development of simple parts has demonstrated the capabilities of OFS to control physical characteristics of the part (the flow front, temperature, residual strain and curing degree). The comparison of the measured characteristics with numerical simulations carried out in collaboration with ESI showed a good correlation.Finally, instrumentation has demonstrated the capacity of composite tool made by HexTool to minimize the residual stresses due to the tool/part interaction.

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