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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

Magnesium - Einfluss der Textur auf das Umformverhalten /

Gehrmann, Robert. January 2004 (has links)
Zugl.: Aachen, Techn. Hochsch., Diss., 2003.
2

Festigkeits- und Schädigungsverhalten von Magnesiumfeinblech in experimenteller und numerischer Simulation

Henseler, Thorsten 17 June 2020 (has links)
Erstmalig wird das Forschungsziel, für Magnesiumfeinblech einen experimentell validierten, gefüge- und mechanismenbasierten Parametersatz für die numerische Verformungs- und Schädigungssimulation unter Berücksichtigung der anisotropen Verfestigung zu ermitteln, erreicht. Damit wird dem ansteigenden Bedarf anwendungsrelevanter Werkstoffmodelle für die Entwicklung von Mg-Blechbauteilen entgegengekommen. Besonders die Formulierung von gekoppelten Schädigungsmodellen scheitert bis jetzt an der lückenhaften experimentellen Ermittlung von Schädigungsparametern. Daher sieht die vorliegende Arbeit vor, ein numerisches Modell für die Anwendung in der FEM-Simulation zur Verfügung zu stellen. Es wurden speziell für Feinblech relevante Charakterisierungsmethoden für die Parametrisierung eines gekoppelten Schädigungsmodells unter Berücksichtigung der Orthotropie eingesetzt. Die Anwendung erfolgte anhand von 1,0 mm dünnem AZ31 Feinblech eines über das Gießwalzverfahren mit anschließendem Warmwalzprozess hergestellten Coils. / For the first time the research goal of determining an experimentally validated, microstructureand mechanism-based parameter set for the numerical deformation and damage simulation under consideration of anisotropic hardening has been achieved for magnesium thin sheet. This will meet the increasing demand for application-relevant material models for the development of Mg sheet metal components. In particular, the formulation of coupled damage models has so far failed due to the incomplete experimental determination of damage parameters. Therefore, the present thesis provides a numerical model for the application in FEM simulation. Characterization methods relevant for thin sheet metal were used for the parameterization of a coupled damage model under consideration of the orthotropy. The application was based on 1.0 mm thin AZ31 sheet metal of a coil produced by the twin-roll casting process with subsequent hot-rolling process.
3

Thermo-Mechanical Modelling of Wire-Arc Additive Manufacturing (WAAM) of Semi-Finished Products

Graf, Marcel, Hälsig, Andre, Höfer, Kevin, Awiszus, Birgit, Mayr, Peter 13 February 2019 (has links)
Additive manufacturing processes have been investigated for some years, and are commonly used industrially in the field of plastics for small- and medium-sized series. The use of metallic deposition material has been intensively studied on the laboratory scale, but the numerical prediction is not yet state of the art. This paper examines numerical approaches for predicting temperature fields, distortions, and mechanical properties using the Finite Element (FE) software MSC Marc. For process mapping, the filler materials G4Si1 (1.5130) for steel, and AZ31 for magnesium, were first characterized in terms of thermo-physical and thermo-mechanical properties with process-relevant cast microstructure. These material parameters are necessary for a detailed thermo-mechanical coupled Finite Element Method (FEM). The focus of the investigations was on the numerical analysis of the influence of the wire feed (2.5–5.0 m/min) and the weld path orientation (unidirectional or continuous) on the temperature evolution for multi-layered walls of miscellaneous materials. For the calibration of the numerical model, the real welding experiments were carried out using the gas-metal arc-welding process—cold metal transfer (CMT) technology. A uniform wall geometry can be produced with a continuous welding path, because a more homogeneous temperature distribution results.

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