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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

Hluboké vrtání leteckého dílu / Deep drilling of an aeronautical part

Klíma, Jan January 2013 (has links)
Diploma thesis deals with problems about deep drilling of aeronautical part made of aluminum alloy EN AW 7075 T7351. This work is focused on the material properties component and current aluminum alloys processing. Further it contains a part delicated to various kinds of technologies of deep drilling, primarily is focused to gun drilling. Describes a tool, technology and conditions in gun drilling of deep holes with focused to analysis of the forces. Then it compares contemporary manufacturing technology of part drilling in cooperation and proposes an innovative technology of manufacturing. This project is accomplished with technical-economical evaluation.
12

Zpracování vysokopevnostní hliníkové slitiny EN AW 7075 technologií SLM / Processing of high-strength aluminum alloy EN AW 7075 using SLM technology

Skalický, Petr January 2017 (has links)
This diploma thesis deals with processing of high strength aluminum alloy EN AW 7075 by Selective Laser Melting and verify the influence of process parameters on relative density and mechanical properties. The theoretical part contains an introduction to additive manufacturing of aluminum alloys, the influence of process parameters and description of processes occuring during SLM production. Based on the theoretical part were prepared experiments and method of evaluation. Samples were produced by melting metallurgical powder using ytterbium laser with a maximum output power of 400 W. This diploma thesis also describes the formation and growth of cracks inside the material, which so far in the literature for alloy EN AW 7075 were not described. As the result, the process parameters dependence on the relative density and an overview of this aluminum alloy processing by SLM technology is determined.
13

Kvalifikace postupu svařování hliníkové slitiny AW-5083 H111 / Qualification of welding procedure for aluminium alloy AW-5083 H111

Krejza, Jan January 2019 (has links)
The diploma thesis deals with the qualification of welding process of aluminum alloy EN AW-5083 H111. This aluminum alloy was used to make a Venturi tube. Therefore, a literature review has been developed dealing with the properties and use of aluminum and its alloys. The next chapter deals with the weldability of aluminum, aluminum alloys and the weldability of EN AW-5083 alloy. Part of the work is devoted to the used TIG method and its specifics when welding aluminum materials. The practical part of the thesis deals with the actual qualification of welding procedures according to the relevant standard and evaluation of production conditions according to the product standard. The last chapter deals with the overall manufacturing process of the Venturi tube.
14

Návrh snížení počtu svarů u rámových dveří kolejových vozidel z Al slitin / Proposal of welds number reduction on aluminium aloys frame doors for rail vehicles

Šplíchal, Jan January 2019 (has links)
This Diploma thesis presents possible proposals of welds number reduction frame doors for rail vehicles welded from profiles from aluminium alloy EN AW 6060, which is heat treated by temper T66. Profiles are welded by TIG process with additional material S Al 5087 (AlMg4,5MnZr). The heat treatment by the welding cycle causes a change in structure of basic material and decrease of mechanical properties due to dissolution of precipitates. To measure the necessary mechanical properties of the material after welding a tensile test was performed on the delivered samples. The resulting values from tensile test were subsequently used as cut – off values in the new door frame design by FEM simulation in Virtual Performance Solution software with PAM – Crash extension. The newly designed frame was welded according to the necessary welding procedure specifications, which are also part of the thesis. The conclusion is devoted to the economic evaluation of the current and new design of the door frame.
15

Výroba součásti "regulační člen" protlačováním / Production of components "control element" extrusion

Stříbrný, Jan January 2013 (has links)
The project elaborated in frame of engineering studies branch Engineering technology submitted technology design of manufacturing a control element by extrusion – part of aluminium alloy EN AW 6082. On the base of literature study of the cold forming problems and calculations was designed procedure on one operation. Semi-finished product was chosen cut block rods with a diameter of 43.5 mm and length of 17,4 mm. The production is designed for toggle stamping press LLR 400 (producer Šmeral Brno a.s.) with a nominal force 4000 kN. Extrusion punch and extrusion die are made of steel alloy 19 830.4 heat-worked according to drawing documentation.
16

Identifikace únavového poškození Al slitiny zpracované technologií SLM s využitím metody akustické emise / Identification of fatigue damage Al alloy treated with SLM technology using acoustic emission method

Zemanová, Lucie January 2016 (has links)
The aim of the diploma thesis is to study fatigue properties of EN AW-2618A aluminium alloy produced by selective laser melting (SLM). S-N diagrams of reference alloy and SLM material depending on manufacturing conditions were constructed. Reference alloy had the same chemical composition as the SLM material, but it was made by traditional technology (by extruding). While testing, acoustic emission (AE) and resonant frequency of loading was monitored. Fractographic analyses of fracture surfaces were performed. It was found, that SLM material has significantly worse fatigue performance. Fatigue properties are strongly dependent on SLM process parameters settings and precise observance of procedure. The most significant differences in cyclic degradation were found in the length of the stages of fatigue. The more homogeneous the material is, the longer the nucleation stage compared to the total lifetime is. The main source of AE in case of the reference material is plastic deformation on the tip of the crack. For SLM testing, stronger acoustic activity was recorded, because brittle fracture of the material between discontinuities, which is stronger AE source, is more frequent.
17

Modélisation et simulations numériques pour des systèmes de la mécanique des fluides avec contraintes : application à la biologie et au trafic routier / Modeling and numerical simulations for fluid mechanics systems with constraints : application to biology and road traffic

Polizzi, Bastien 29 September 2016 (has links)
Cette thèse est consacrée à l'étude de systèmes d'équations aux dérivées partielles. En particulier nous nous intéressons à des systèmes issus de la mécanique des fluides avec contraintes qui permettent de décrire de manière continue en temps et en espace des quantités physiques telles que la densité ou la vitesse. Dans ce cadre nous construisons des modèles pour la biologie : modélisation de la croissance d'un biofilm de micro-algues et modélisation du gros intestin et de sa couche de mucus. Ces modèles sont ensuite testés numériquement à l'aide de schémas numériques spécifiquement élaborés pour ces modèles. Cette thèse est complétée par une étude numérique du modèle d'Aw-Rascle avec contrainte pour le trafic routier / This thesis is devoted to the study of partial differential equation systems. In particular, we are interested in constrained systems coming from the fluid mechanics field which allow to describe, in time and space, physical quantities such as density or speed. In this context we build models for biology: modeling of the growth of micro-algae biofilms and modeling of the large intestine and its mucus layer. These models are then tested numerically using numerical schemes specifically developed for these models. This thesis is supplemented with a numerical study of Aw-Rascle model with constraint for road traffic
18

Ett publikt vardagsrum

Söderlind, Simon January 2018 (has links)
Med ett nytt perspektiv att se arkitekturens roll i staden, har jag arbetat med att utveckla och testa mig fram via olika interventioner för att se hur sociala samspel och möten kan uttryckas i den byggda miljön. Mitt examensarbete går ut på att jag tar upp Mattias Kärrholms avhandling, Arkitekturens territorialitet, där hans diskussion angående territoriell makt i förhållande till den gestaltning som finns i stadens olika offentliga rum ligger till grund för mitt arbete.Med ett fokus på hur det offentliga rummets gestaltningar kan (eller inte kan) stödja ett icke-kommersiellt anspråkstagande ur ett socialt perspektiv, skapade jag ett tillfälligt rum, ett publikt vardagsrum, för att se hur detta vardagsrum påverkade platsen och de människor som rörde sig där. Platsen för mina interventioner är Hjulhamnsgatan i Malmö. Vardagsrummet är ett resultat av mina interventioner som har grundat sig ur Kärrholms teorier, med ett extra stort fokus på vad han själv kallar för territoriella produktionsformer.Huvudfråga:Hur kan en offentlig gata som idag inte har någon tydlig och uttalad social användning, tydligare visa sina möjligheter som mötesplats för människor?Underfrågor:Vilka relationer till platsen har människorna och hur påverkar de olika relationerna varandra?Vilka brister finns på platsen och hur kan de transformeras för att förbättra möjligheterna till en mötesplats? / With a new perspective to see the role of architecture in the city, I have worked to develop and test various interventions to see how social interactions and meetings can be expressed in the built environment. My degree project is based on examining Mattias Kärrholm’s dissertation, the Territoriality of Architecture, where his discussion of territorial power in relation to the shape of the city’s various public spaces forms the basis of my work.With a focus on how the public spaces can (or can not) support a non-commercial claim from a social perspective, I created a temporary room, a public living room, to see how this living room affected the site and the people who moved with in it. The place for my interventions is Hjulhamnsgatan in Malmö, Sweden. The living room is a result of my interventions, based on Kärholm’s theories, with an extra focus on what he calls forms of territorial production.My main research question:How can a public street, which today has no clear and pronounced social use,more clearly showcase their opportunities as a meeting place for people?Second Questions:What relationships with the place do people have and how they affect the different relationshipseach other?What shortcomings are in place and how can they be transformed to improve the possibilities for a meeting place?
19

Zusammenhänge zwischen Werkstoff- und Oberflächenzustand und der Korrosionsanfälligkeit von Metallen / Correlations between material and surface state and the corrosion susceptibility of metals

Mehner, Thomas 26 May 2017 (has links) (PDF)
Das Ausmaß der Korrosion kann durch den Werkstoff- und Oberflächenzustand gesteuert werden. Wichtige Einflussgrößen sind die Rauheit, Kristallitgröße, Mikroverzerrung, Textur und Eigenspannungen. Am Beispiel von Kaltwalzprozessen werden Abhängigkeiten dieser Größen vom Umformgrad aufgezeigt, die in numerische Simulationen implementierbar sind und somit die Aussagefähigkeit der Berechnungen maßgeblich erhöhen können. Es wird in der vorliegenden Arbeit ein Modell zur qualitativen und quantitativen Erfassung der Zusammenhänge zwischen den Einflussgrößen und der Korrosionsrate vorgeschlagen. Am Beispiel eines unlegierten Stahls (DC04) kann damit die minimal mögliche Korrosionsrate in Schwefelsäure berechnet sowie ein optimierter Ablauf der Prozessroute beim Kaltwalzen abgeleitet werden, um dieses Minimum zu erreichen. Das Modell ist auf weitere Korrosionssysteme übertragbar, was am Beispiel von EN AW-1050/Schwefelsäure aufgezeigt wird. / The extent of corrosion can be controlled by the material and surface state. Important parameters are: roughness, crystallite size, microstrain, texture and residual stresses. Using the example of cold-rolling processes, the dependencies of these parameters on the plastic strain are shown that can be implemented in numerical simulations and allow increasing the information extracted from the calculations significantly. A model is proposed for determining qualitative and quantitative correlations between the corrosion-affecting parameters and the corrosion rate. Using a carbon steel (DC04), the minimal corrosion rate in sulphuric acid can be calculated and an appropriate processing route is suggested. The model can be adopted for other corrosion systems, which is shown for EN AW-1050/sulphuric acid.
20

Zusammenhänge zwischen Werkstoff- und Oberflächenzustand und der Korrosionsanfälligkeit von Metallen

Mehner, Thomas 26 May 2017 (has links)
Das Ausmaß der Korrosion kann durch den Werkstoff- und Oberflächenzustand gesteuert werden. Wichtige Einflussgrößen sind die Rauheit, Kristallitgröße, Mikroverzerrung, Textur und Eigenspannungen. Am Beispiel von Kaltwalzprozessen werden Abhängigkeiten dieser Größen vom Umformgrad aufgezeigt, die in numerische Simulationen implementierbar sind und somit die Aussagefähigkeit der Berechnungen maßgeblich erhöhen können. Es wird in der vorliegenden Arbeit ein Modell zur qualitativen und quantitativen Erfassung der Zusammenhänge zwischen den Einflussgrößen und der Korrosionsrate vorgeschlagen. Am Beispiel eines unlegierten Stahls (DC04) kann damit die minimal mögliche Korrosionsrate in Schwefelsäure berechnet sowie ein optimierter Ablauf der Prozessroute beim Kaltwalzen abgeleitet werden, um dieses Minimum zu erreichen. Das Modell ist auf weitere Korrosionssysteme übertragbar, was am Beispiel von EN AW-1050/Schwefelsäure aufgezeigt wird. / The extent of corrosion can be controlled by the material and surface state. Important parameters are: roughness, crystallite size, microstrain, texture and residual stresses. Using the example of cold-rolling processes, the dependencies of these parameters on the plastic strain are shown that can be implemented in numerical simulations and allow increasing the information extracted from the calculations significantly. A model is proposed for determining qualitative and quantitative correlations between the corrosion-affecting parameters and the corrosion rate. Using a carbon steel (DC04), the minimal corrosion rate in sulphuric acid can be calculated and an appropriate processing route is suggested. The model can be adopted for other corrosion systems, which is shown for EN AW-1050/sulphuric acid.

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