Einsatz der Hochtemperatur-Photogrammetrie in der Messung der akkumulierten lokalen Verformungen und der Rissinitiierung

Translated title of the contribution: Analysis of accumulated strains and crack initiation by means of high temperature photogrammetry

Thomas Wlanis

Research output: ThesisDiploma Thesis

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Abstract

In hot forming processes undesirable cracks and strain localization can appear, which demands a proper analysis of the process, e.g. by a finite element analysis coupled with damage models. For these models parameters have to be determined and the forming process has to be analysed. A possibility for comparing the simulation with the real process is the use of a photogrammetry system. The implementation of such a system is describted in the literature at room temperature in detail, however, its applicability for the hot forming process was investigated in this thesis. For the evaluation of the usability of the photogrammetric system Aramis for hot forming experiments, nickel-based alloys and aluminium alloys have been tested. The compression tests were performed on a Servotest and the 1MN hydraulic press of the Chair of Metal Forming. For the interpretation of the images the specimens had to be prepared with a pattern. There are different methods to get such a pattern. The images were analysed by the Aramis software to get values for Mises strain, Tresca strain, displacement, major strain and minor strain and other values. Additionally, information about deformation characteristic and tool movement during the forming were gathered. Experiments showed that a photgrammetric system can be used for measuring strain localisation and crack initiation. During that evaluation some important aspects were disscused. An important factor was the quality of the pattern. For the crack analyses they have to appear in an evaluable area of the specimen. Many factors like image rate, exposure time, etc. depend on each other, which need additional investigations in future.
Translated title of the contributionAnalysis of accumulated strains and crack initiation by means of high temperature photogrammetry
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Sommitsch, Christof, Supervisor (internal)
Award date19 Dec 2008
Publication statusPublished - 2008

Bibliographical note

embargoed until null

Keywords

  • Photogrammetry hot forming crack initiation strain localisation compression test

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