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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.
11

Characterization of Friction-stir Riveting AA5754

Wang, Zixi January 2014 (has links)
No description available.
12

Influence of corrosion damage topography on fatigue properties in longitudinal fuselage lap joints /

Cook, Jonathan January 1900 (has links)
Thesis (M. Eng.)--Carleton University, 2004. / Includes bibliographical references (p. 177-183). Also available in electronic format on the Internet.
13

Radíální nýtovačka / Orbital Rivet Machine

Hloušek, Petr January 2008 (has links)
The merit of this graduation thesis is to get known with a moulding technology - non rewirable bond to understand principle and design one-purpose riveting machine. To show aknowligement and orientation in literature create a design analyze features and disadvantages types of constuction and be able to assure stability and safety long life of a head frame. Pick up and one another put together suitable working units and be able to interpret the results.
14

Self-Piercing Riveting of High Ductility Al-Fe-Zn-Mg Casting Alloy (Nemalloy HE700) in F Temper: Modelling, Simulation and Experimental Analysis

Guo, Yunsong January 2024 (has links)
This thesis presents a comprehensive investigation into the feasibility and optimization of self-piercing riveting (SPR) for joining high-ductility die-cast aluminum alloy Nemalloy HE700 in F temper (as-cast) condition to dissimilar sheet materials, namely wrought aluminum alloy 6082-T6 and dual-phase steel DP600. The study demonstrates successful SPR joining of HE700 to these materials, with optimized process parameters and joint quality meeting automotive industry standards. Systematic experimental studies were conducted to investigate the effects of key SPR process parameters, including die geometry, ring groove depth, rivet hardness, and length, on joint quality and performance. Microstructural characterization revealed distinct patterns of grain flow and localized hardening in HE700 around the rivet and die features, providing insights into its deformation characteristics. Finite element simulations, incorporating advanced material models such as Johnson-Cook plasticity and failure for AA6082 and DP600, and Voce hardening with Gurson-Tvergaard-Needleman void damage model for HE700, were developed and extensively validated against experimental results. The simulations accurately predicted potential failure sites in HE700, aligning with experimental observations of crack initiation. Numerical parametric studies demonstrated the intricate effects of process parameters and material properties on the stress and strain distributions, material flow, and damage accumulation during SPR. The research contributes to the growing body of knowledge on advanced joining techniques for dissimilar materials, supporting vehicle lightweighting efforts. It establishes a comprehensive methodology integrating experiments, microstructural characterization, and simulations for studying and optimizing SPR processes for low ductility casting alloys, serving as a blueprint for future research and industrial implementation. The findings demonstrate the viability and potential of SPR technology for integrating high-ductility die-cast aluminum alloy HE700 into lightweight automotive body structures, paving the way for its wider industrial adoption. / Thesis / Master of Applied Science (MASc) / This research explores the potential of using a novel high-ductility aluminum alloy, Nemalloy HE700, in self-piercing riveting (SPR) - a modern joining technique for automotive manufacturing. The study aims to optimize the SPR process for joining HE700 to other commonly used automotive materials, such as aluminum alloys and high-strength steels, without compromising joint quality. By conducting practical experiments and computer simulations, the research identifies the best process parameters, such as rivet design and die shape, that result in strong, reliable joints meeting automotive industry standards. The findings demonstrate the successful use of HE700 in SPR, offering a promising solution for creating lighter, more fuel-efficient vehicles. This work contributes to the development of advanced joining technologies for sustainable transportation, making vehicles more environmentally friendly while maintaining high performance and safety standards.
15

Comparative analysis between friction stir welding and automatic riveting in the assembly of aircraft structures

Sala Diakanda, Serge N. 01 April 2003 (has links)
No description available.
16

Entwicklung und Verifizierung eines vorlochfreien mechanischen Fügeverfahrens zum Verbinden von Leichtmetallen und Faser-Kunststoff-Verbunden / Development and varification of a mechanical joining process for joining lightweight metals and fibre reinforced plastics without the need of a prehole

Podlesak, Frank 27 April 2017 (has links) (PDF)
Die Mischbauweise stellt eine Möglichkeit dar, insbesondere im Automobilbau, aber auch in anderen Industriezweigen Leichtbau zu betreiben. Dazu werden verschiedenartige Werkstoffe miteinander kombiniert. Vorzugsweise handelt es sich um Kombinationen aus faserverstärkten Kunststoffen und Leichtmetallen. Nach dem Motto “Der richtige Werkstoff am richtigen Ort” können so belastbare und gleichzeitig leichte Konstruktionen realisiert werden. Eine große Herausforderung besteht dabei jedoch im Fügen solch unterschiedlicher Werkstoffe. Aufgrund großer Unterschiede in Bindungsart und Schmelztemperatur sind klassische Fügeverfahren nicht anwendbar. Zum Verbinden von Metallen mit Faser- Verbund-Werkstoffen (FKV) wurden deswegen vorhandene Technologien adaptiert oder neue entwickelt. Im Rahmen dieser Dissertation wurde mit dem modifizierten Blindnieten ein neuer Lösungsansatz entwickelt, der sowohl mechanische als auch thermische Fügeverfahren miteinander kombiniert. Dazu wird ein rotierender Blindniet in sich überlappende Bleche getrieben und das darunter liegende Material unter Ausbildung einer Hülse aus dem Oberblech verdrängt. Anschließend wird der Niet ausgeformt und der Prozess ist abgeschlossen. Durch die Reibwärme wird die thermoplastische Matrix des FKV geschmolzen und die Fasern werden beweglich und können verdrängt werden. Dadurch kommt es zu einer geringeren Faserschädigungen und es können Delaminationen komplett vermieden werden. Untersuchungen wurden vorzugsweise an Materialkombinationen in Mischbauweise durchgeführt. Es wurden Aluminium- und Magnesiumbleche mit verschiedenen FKV mit Glas- oder Kohlefaserverstärkung gefügt. Für eine große Anwendungsbreite wurden ebenso Verbindungen von mehreren Metallblechen untersucht. Alle Kombinationen konnten so gefügt werden, dass in relativ kurzer Prozesszeit eine qualitativ hochwertige Verbindung entsteht. Mit einer geeigneten Parameterwahl sind Fügezeiten unter drei Sekunden möglich. Die mechanisch technologischen Gütewerten zeigen, dass mittels modifiziertem Blindnieten hergestellte Verbindungen mindestens die gleiche Lasten aufnehmen können, wie konventionelle Verfahren. Unter Scherbelastung kann die Belastbarkeit um bis zu 68 % gesteigert werden. Es hat sich gezeigt, dass mit dem neuen Verfahren eine wirtschaftliche Lösung für den Mischbau zur Verfügung steht. / Composite constructions provide an opportunity to introduce lightweight design in automotive and other industries. Therefore different kind of materials are combined. Preferably, these are combinations of fibre reinforced plastics and lightweight metal alloys. With the slogan "the right material at the right place" tough and lightweight constructions can be realized. A big challenge the joining of these different materials. Because of big differences in the chemical bindings and in the melting temperature, conventional joining methods cannot be used. To join fibre reinforced plastics (FRP) existing processes were adapted or newly developed. In the course of this work with the modified blind riveting a new approach was developed, which combines mechanical and thermal joining processes. Therefore a rotating blind rivet is penetrated through two overlapping sheets by deforming the sheet material. After that the rivet is set and the process finished. Because of the friction heat the thermoplastic matrix of the FRP is slightly melted and the fibres can be moved without breaking them. Investigations were done mainly with lightweight material combinations. Sheets made out of aluminum and magnesium were joined with glass or carbon fibre reinforced plastic sheets. For a wider application field also combinations of two metal sheets were investigated. All combinations could be joined in a relatively short cycle time and high quality. So it is possible to reach a joining time of under 3 seconds. Under shear load the strength of joints made by modified blind riveting can be up to 68 % higher than conventional riveted joints. It has been shown that the new process can be exploited economically.
17

Stress And Fracture Analysis Of Riveted Joints

Kecelioglu, Galip 01 November 2008 (has links) (PDF)
The objective of this study is to model and analyze a three dimensional single riveted lap joint (with and without a crack). By using finite element method, stress and fracture analyses are carried out under both the residual stress field and external tensile loading. Using a two step simulation, riveting process and subsequent tensile loading of the lap joint are simulated to determine the residual and overall stress state. Residual stress state due to riveting is obtained by interference and clamping misfit method. By employing different interference and clamping misfit values, the effects of riveting process parameters on stress state are examined. Two cracks namely the semi elliptical surface crack at faying surfaces of plates and the quarter elliptical corner crack at rivet hole are the most widely observed crack types in riveted joints. Fracture analysis of cracked riveted joints is carried out by introducing these two crack types to the outer plate at a plane perpendicular to the loading. The mixed mode stress intensity factors (SIFs) and energy release rates (G) around the crack front are obtained by using displacement correlation technique (DCT). Effects riveting process parameters (interference and clamping ratios) and geometrical parameters (crack shape and size) on fracture parameters are studied. The stress intensity factor solutions presented herein could be useful for correlating fatigue crack growth rates, fracture toughness computation, and multiple site damage (MSD) analysis in aircraft bodies.
18

Efeito da anisotropia na propagação da deformação induzida em ligas 2024 termicamente tratadas / Effect of anisotropy in induced propagation of deformation in 2024 termically treated alloys

Paiva, Sergio Ricardo de 26 January 2018 (has links)
Submitted by SERGIO RICARDO DE PAIVA null (sergio.paiva@embraer.com.br) on 2018-03-01T23:18:05Z No. of bitstreams: 1 Dissertação Sergio Paiva_Versão Final_F_Alterações.pdf: 4152807 bytes, checksum: bd7266ab07460bb304ec051893e2dce2 (MD5) / Approved for entry into archive by Pamella Benevides Gonçalves null (pamella@feg.unesp.br) on 2018-03-02T12:14:34Z (GMT) No. of bitstreams: 1 paiva_sr_me_guara.pdf: 4152807 bytes, checksum: bd7266ab07460bb304ec051893e2dce2 (MD5) / Made available in DSpace on 2018-03-02T12:14:34Z (GMT). No. of bitstreams: 1 paiva_sr_me_guara.pdf: 4152807 bytes, checksum: bd7266ab07460bb304ec051893e2dce2 (MD5) Previous issue date: 2018-01-26 / O processo de rebitagem é largamente utilizado na indústria aeronáutica para fabricação de fuselagens de aviões. Durante esse processo deformações locais são introduzidas nas estruturas por meio da expansão dos rebites devido sua conformação. A deformação plástica causa uma expansão no rebite e consequentemente na estrutura circundante onde o mesmo foi inserido. Este trabalho tem como objetivo analisar o efeito da anisotropia na propagação da deformação induzida em corpos de prova de ligas 2024 que passaram pelo processo de rebitagem, em chapas de alumínio termicamente tratadas. O experimento avaliou como a geometria do grão, relacionadas ao tamanho e forma dos mesmos, assim como o efeito do tratamento térmico, influenciam na expansão diametral. Foram empregados corpos de prova de liga de alumínio 2024 com tratamento térmico T3 e TO, comumente utilizadas pela indústria aeronáutica, em diferentes direções de grãos, longitudinal e transversal, onde foram cravados rebites e avaliado o alongamento dos corpos de prova pelo efeito da rebitagem. Os resultados obtidos comprovam que a anisotropia exerce uma influência significativa no fator expansão e que a deformação plástica na direção transversal de laminação foi aproximadamente 60% maior que na direção de laminação para os dois tratamentos térmicos analisados. Também foi constatado que o tratamento térmico do material influencia no fator expansão. Verificou-se que a expansão dos corpos de prova recozidos foi o dobro nas direções transversal e longitudinal quando comparados com os corpos de prova de condição envelhecida / The riveting process is wide used at Aerospace industry during airplane fuselage construction. During this process, local deformations are introduced in the structures by the rivet expansion, due the plastic deformation. The plastic deformation makes the rivet expand inside the hole and consequently, the structure around the rivet expand too. The goal of this research is to analyses the anisotropy effect in the squeezing force propagation in specimens of 2024 alloys that were submitted to the riveting process, in aluminum plates heated treatment. The research analyzed the grain geometry related to size and form, and how the heat treatment effect influences the hole diameter expansion. It was used specimens of aluminum alloy 2024 T3 and TO, commonly used in aerospace industry, in different grains directions, longitudinal and transversal. Rivets were installed and the specimen stretching was analyzed. The results prove that the anisotropy have a significative influence in the expansion factor, the plastic deformation in the transversal rolled direction was about 60% bigger than rolled direction for the two heat treatment analyzed. Also, it was verified that the material heat treatment influences the factor expansion. According the results the expansion in the relieved specimens condition were the double in the transversal and longitudinal direction than the aging specimens condition
19

Aplikace svařování třením v leteckých konstrukcích / Application of Friction Stir Welding in Aircraft Structures

Šrubař, Martin January 2009 (has links)
Slitiny hliníku řad 2XXX a 7XXX nejsou shledávány jako svařitelné s použitím tradičních metod svařování. Jsou však široce používány v leteckých a kosmických konstrukcích. Obvyklý způsob jejich spojování je pomocí nýtování. Nově vznikající technologie lineárního svařování třením rotujícím nástrojem (Friction Stir Welding - FSW) již ukázala slibné výsledky při svařování těchto slitin. V této práci jsme prozkoumali aplikace technologie FSW v leteckých konstrukcích zejména jako náhradu nýtování na panelech vyztužených stringery. Sestavili jsme výrobní postup pro daný panel a navrhli další kroky k jeho optimalizaci. Dále jsme sestavili znalostní bázi základních svařovacích parametrů a porovnali jsme nýtování a FSW na jednoduchém modelu využitím metody konečných prvků a s cílem identifikovat rozdíly v charakteru rozložení napětí v těchto vzorcích.
20

Návrh lisovacích přípravků na manifoldové sestavy kondenzátoru automobilové klimatizace / Design of pressing machines for manifold assembly of condensers in car air-conditioning unit

Juriga, Jakub January 2016 (has links)
The diploma thesis deals with the design of pressing machines for manifold assembly of condensers in the car air-conditioning unit. The problem of the current assembling process is its inefficiency. Semi-automated assembly using pneumatic pressing machines eliminates this problem. In the theoretical part the air-conditioning components, current state of assembly and calculating base of pressing are described. In the practical part the test of pressing force was conducted. Based on this test, the design of four pneumatic pressing machines was accomplished. In the final part of the work, evaluation of the whole project is provided.

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