skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Consistent Parameters for Plastic Anisotropy of Sheet Metal (Part 1-Uniaxial and Biaxial Tests)

Abstract

The anisotropy parameters for sheet metal used hitherto are mainly determined by uniaxial tensile tests. Such tests, however, do not give sufficient information about the yield locus and the forming behaviour in that range where the two principal tensile stresses are of similar magnitude like in stretch forming. The same applies for combined tensile and compressive stress like in deep-drawing. To fill these gaps, new parameters are defined. Their experimental determination is briefly discussed.The 'equibiaxial yield stress' and 'equibiaxial anisotropy' which refer to equibiaxial tensile stress can be determined by cross tensile tests. However, these require a special apparatus. Alternatively experiments for obtaining plane strain can be applied for determining the equibiaxial parameters indirectly. This is possible using conventional tensile testing machines. In this case also anisotropy parameters for plane-strain deformation, the 'semibiaxial anisotropy' in rolling and transverse direction, can be determined.

Authors:
;  [1];  [2];  [3]
  1. Institut fuer Statik und Dynamik der Luft -und Raumfahrtkonstruktionen, Universitaet Stuttgart, Pfaffenwaldring 27, D-70569 (Germany)
  2. Institut fuer Umformtechnik, Universitaet Stuttgart, Holzgartenstr. 17, D-70174 Stuttgart (Germany)
  3. Technical University of Cluj-Napoca, C. Daicoviciu nr. 15, 400020 Cluj-Napoca (Romania)
Publication Date:
OSTI Identifier:
21057037
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 907; Journal Issue: 1; Conference: 10. ESAFORM conference on material forming, Zaragoza (Spain), 18-20 Apr 2007; Other Information: DOI: 10.1063/1.2729542; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; ANISOTROPY; DEFORMATION; DRAWING; METALS; PLASTICITY; ROLLING; SHEETS; STRAINS; STRESSES; TENSILE PROPERTIES; TESTING

Citation Formats

Poehlandt, K., Schoeck, J., Lange, K., and Banabic, D. Consistent Parameters for Plastic Anisotropy of Sheet Metal (Part 1-Uniaxial and Biaxial Tests). United States: N. p., 2007. Web. doi:10.1063/1.2729542.
Poehlandt, K., Schoeck, J., Lange, K., & Banabic, D. Consistent Parameters for Plastic Anisotropy of Sheet Metal (Part 1-Uniaxial and Biaxial Tests). United States. doi:10.1063/1.2729542.
Poehlandt, K., Schoeck, J., Lange, K., and Banabic, D. 2007. "Consistent Parameters for Plastic Anisotropy of Sheet Metal (Part 1-Uniaxial and Biaxial Tests)". United States. doi:10.1063/1.2729542.
@article{osti_21057037,
title = {Consistent Parameters for Plastic Anisotropy of Sheet Metal (Part 1-Uniaxial and Biaxial Tests)},
author = {Poehlandt, K. and Schoeck, J. and Lange, K. and Banabic, D.},
abstractNote = {The anisotropy parameters for sheet metal used hitherto are mainly determined by uniaxial tensile tests. Such tests, however, do not give sufficient information about the yield locus and the forming behaviour in that range where the two principal tensile stresses are of similar magnitude like in stretch forming. The same applies for combined tensile and compressive stress like in deep-drawing. To fill these gaps, new parameters are defined. Their experimental determination is briefly discussed.The 'equibiaxial yield stress' and 'equibiaxial anisotropy' which refer to equibiaxial tensile stress can be determined by cross tensile tests. However, these require a special apparatus. Alternatively experiments for obtaining plane strain can be applied for determining the equibiaxial parameters indirectly. This is possible using conventional tensile testing machines. In this case also anisotropy parameters for plane-strain deformation, the 'semibiaxial anisotropy' in rolling and transverse direction, can be determined.},
doi = {10.1063/1.2729542},
journal = {AIP Conference Proceedings},
number = 1,
volume = 907,
place = {United States},
year = 2007,
month = 4
}
  • To include the case of deep-drawing (without blank-holder), states of combined tensile and compressive stress have to be considered whereby it is necessary to define two more anisotropy parameters. They are called 'tensile-compressive anisotropy' in rolling and transverse direction. Finally, a new consistent system of 'true' anisotropy parameters is presented. They are defined as the difference between the experimentally determined anisotropy parameters and the values which would be obtained in case of isotropy. They all are zero for isotropic materials.
  • Ion sculpting of ultrathin Fe/Ag(001) films induces the self-assembled formation of nanometric surface ripples oriented along the ion beam direction and the corresponding onset of an in-plane uniaxial contribution to magnetic anisotropy. The authors show that fine tuning of the ion dose impinging on the film allows to tailor the in-plane magnetic anisotropy of such films from purely biaxial in the as-grown state to purely uniaxial. The magnitude of magnetic anisotropy in the pure uniaxial state can be tailored by varying the Fe film thickness prior to irradiation.
  • The objective of the present work was to establish the effect of normal plastic anisotropy on the tensile behavior of sheet specimens. To this end, theoretical analyses were conducted in two major areas. In the first, the influence of r on the transverse stresses and the stress-correction factor during neck development were determined. In the second area of investigation, these results were implemented into a finite difference (direct-equilibrium) simulation of the sheet tension test to establish the effect of r on the stress-strain behavior and ductility.
  • A continuum mechanics model has been developed on the basis of Hill`s theory of orthogonal anisotropy for predicting global mechanical properties of sheets with a through-thickness texture gradient and strength gradient. By the present model, the global r value and yield and flow stresses of the entire sheet can be predicted from the local anisotropic parameters, yield and flow stresses which are given as arbitrary functions of the through-thickness position of the sheet.