Determination of characteristic values of materials for sheet metal forming

Head

Researcher

Funding period:

Permanent

Abstract

Material testing is used to determine characteristic values which are needed as input parameters in finite element simulations. The material values can be determined with a multitude of tests, e.g. tension tests, compression tests, Nakajima tests, shear tests and bending tests as well as tests with load reversal. Modern and complex yield criteria, for example the Barlat 2000 criterion, require the yield point under biaxial loading. The biaxial tensile test can therefore be used to achieve an additional data point in the first quadrant of the yield locus, which describes the point of plastic yielding under different loading conditions. At the LFT, a testing device was developed, in which the arms of a cruciform specimen can be subjected to a tensile load. Equibiaxial tension is achieved if the tensile forces at the end of the cruciform specimen are chosen equally. There are also other balances of forces possible. The strain distribution in the middle of the specimen is detected with an optical strain measurement system using a CCD camera.


Cruciform specimen and testing device for biaxial tensile test (developed at the LFT)

Research groups

Publications

2015

Merklein, M.; Tsoupis, I.; Gnibl, T.; Lechner, M.:
Innovative manufacturing solutions for the efficient production of car bodies.
In: Schmeing, K. (Hrsg.): Forming in Car Body Engineering 2015, Vincentz Network GmbH & Co. KG, Hannover, 2015, S. 67-86

2013

Hotz, W.; Merklein, M.; Kuppert, A.; Friebe, H.; Klein, M.:
Time dependent FLC determination – Comparison of different algorithms to detect the onset of unstable necking before fracture.
Key Eng. Mater. 549(2013), S. 397-404

2012

Merklein, M.; Suttner, S.; Hofmann, M.; Kuppert, A.:
Über die Blechprüfung von heute.
In: M. Borsutzki, G. Moninger (Hrsg.): Tagungsband Werkstoffprüfung, Stahleisen, 2012, S. 1-6

2010

Kuppert, A.; Merklein, M.:
Enhanced Investigation of Flow and Necking Behavior of Sheet Metal within Layer Compression and Tensile Tests.
In: DIMITROV, D. (Hrsg.): Proc. of COMA 10, 2010, S. 147-152

Merklein, M.; Kuppert, A.; Geiger, M.:
Time dependent determination of forming limit diagrams.
Annals of the CIRP 59-1(2010), S. 295-298

Merklein, M.; Kuppert, A.; Mütze, S.; Geffert, A.:
New Time Dependent Method for Determination of Forming Limit Curves Applied to SZBS800.
In: Kolleck, R. (Hrsg.): Proc. 50th Conference of IDDRG 2010, Verlag der Technischen Universität Graz, 2010, S. 489-498

2009

Merklein, M.; Kuppert, A.:
A Method for the Layer Compression Test Considering the Anisotropic Material Behavior.
In: (Hrsg.): International Journal of Material Forming, Springer, 2009, S. 483-486

2008

Kuppert, A.; Merklein, M.:
Ermittlung temperaturabhängiger Werkstoffkennwerte für die Auslegung von Halbwarm- und Warmumformprozessen.
Metall – Magazin für die metallverarbeitende Wirtschaft 05.2008(2008)05, S. 22-25

2007

Merklein, M.; Hußnätter, W.; Staud, D.; Kuppert, A.:
Charakterisierung der Umformeigenschaften von Blechwerkstoffen – Trends und Möglichkeiten der Prüftechnik.
In: Pohl, M. (Hrsg.): Tagungsband Werkstoffprüfung 2007, Stahleisen GmbH, 2007, S. 201-210

2004

Liebertz, H.; Duwel, A.; Illig, R.; Hotz, W.; Keller, S.; Koehler, A.; Kröff, A.; Merklein, M.; Rauer, J.; Staubwasser, L.; Steinbeck, G.; Vegter, H.:
Guideline for the determination of forming limit curves.
In: (Hrsg.): Proceedings of IDDRG 2004, 2004, S. 216-224

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