A material model for warm forming of aluminium sheet

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Abstract

A material model has been developed to simulate the warm forming of Al–Mg sheet. Both the hardening behaviour, including temperature and strain rate effects, and the biaxial stress–strain response of the sheet are considered. A physically-based hardening model according to Bergström is used. This model incorporates the influence of the temperature and strain rate on the flow stress and on the hardening rate based on dynamic recovery. For deformations at constant temperature and strain rate, the Bergström model reduces to the well known Voce hardening model. The Bergström/Voce models can be fitted quite well to the results of monotonic tensile tests of an AA 5754-O alloy. The biaxial stress–strain response of the material is experimentally determined by uniaxial, plane strain, simple shear and equi-biaxial stress tests. It is demonstrated that the widely used Hill ’48 yield locus is inappropriate for simulation of deformation of aluminium. The low Rvalues for aluminium lead to a significant underestimation of the equi-biaxial yield stress. In the simulation of the deep drawing of a cylindrical cup this results in a much too thin bottom of the cup. The Vegter yield criterion is sufficiently flexible to accurately represent the shape of the yield locus and the anisotropy. 1
Original languageEnglish
Title of host publication7th International Conference on Computational Plasticity, COMPLAS VII
EditorsE. Onate, D.R.J. Owen
Place of PublicationBarcelona
PublisherCIMNE Barcelona
Number of pages17
ISBN (Print)84-9599922-6
Publication statusPublished - 2003
Event7th International Conference on Computational Plasticity, COMPLAS 2003 - Barcelona, Spain
Duration: 7 Apr 200310 Apr 2003
Conference number: 7

Conference

Conference7th International Conference on Computational Plasticity, COMPLAS 2003
Abbreviated titleCOMPLAS VII
CountrySpain
CityBarcelona
Period7/04/0310/04/03

Fingerprint

Aluminum sheet
Hardening
Strain rate
Aluminum
Deep drawing
Plastic flow
Yield stress
Recovery
Temperature

Keywords

  • Warm forming
  • Aluminium
  • Finite elements
  • Material model

Cite this

van den Boogaard, A. H., & Bolt, P. J. (2003). A material model for warm forming of aluminium sheet. In E. Onate, & D. R. J. Owen (Eds.), 7th International Conference on Computational Plasticity, COMPLAS VII Barcelona: CIMNE Barcelona.
van den Boogaard, A.H. ; Bolt, P.J. / A material model for warm forming of aluminium sheet. 7th International Conference on Computational Plasticity, COMPLAS VII. editor / E. Onate ; D.R.J. Owen. Barcelona : CIMNE Barcelona, 2003.
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abstract = "A material model has been developed to simulate the warm forming of Al–Mg sheet. Both the hardening behaviour, including temperature and strain rate effects, and the biaxial stress–strain response of the sheet are considered. A physically-based hardening model according to Bergstr{\"o}m is used. This model incorporates the influence of the temperature and strain rate on the flow stress and on the hardening rate based on dynamic recovery. For deformations at constant temperature and strain rate, the Bergstr{\"o}m model reduces to the well known Voce hardening model. The Bergstr{\"o}m/Voce models can be fitted quite well to the results of monotonic tensile tests of an AA 5754-O alloy. The biaxial stress–strain response of the material is experimentally determined by uniaxial, plane strain, simple shear and equi-biaxial stress tests. It is demonstrated that the widely used Hill ’48 yield locus is inappropriate for simulation of deformation of aluminium. The low Rvalues for aluminium lead to a significant underestimation of the equi-biaxial yield stress. In the simulation of the deep drawing of a cylindrical cup this results in a much too thin bottom of the cup. The Vegter yield criterion is sufficiently flexible to accurately represent the shape of the yield locus and the anisotropy. 1",
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van den Boogaard, AH & Bolt, PJ 2003, A material model for warm forming of aluminium sheet. in E Onate & DRJ Owen (eds), 7th International Conference on Computational Plasticity, COMPLAS VII. CIMNE Barcelona, Barcelona, 7th International Conference on Computational Plasticity, COMPLAS 2003, Barcelona, Spain, 7/04/03.

A material model for warm forming of aluminium sheet. / van den Boogaard, A.H.; Bolt, P.J.

7th International Conference on Computational Plasticity, COMPLAS VII. ed. / E. Onate; D.R.J. Owen. Barcelona : CIMNE Barcelona, 2003.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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AU - Bolt, P.J.

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N2 - A material model has been developed to simulate the warm forming of Al–Mg sheet. Both the hardening behaviour, including temperature and strain rate effects, and the biaxial stress–strain response of the sheet are considered. A physically-based hardening model according to Bergström is used. This model incorporates the influence of the temperature and strain rate on the flow stress and on the hardening rate based on dynamic recovery. For deformations at constant temperature and strain rate, the Bergström model reduces to the well known Voce hardening model. The Bergström/Voce models can be fitted quite well to the results of monotonic tensile tests of an AA 5754-O alloy. The biaxial stress–strain response of the material is experimentally determined by uniaxial, plane strain, simple shear and equi-biaxial stress tests. It is demonstrated that the widely used Hill ’48 yield locus is inappropriate for simulation of deformation of aluminium. The low Rvalues for aluminium lead to a significant underestimation of the equi-biaxial yield stress. In the simulation of the deep drawing of a cylindrical cup this results in a much too thin bottom of the cup. The Vegter yield criterion is sufficiently flexible to accurately represent the shape of the yield locus and the anisotropy. 1

AB - A material model has been developed to simulate the warm forming of Al–Mg sheet. Both the hardening behaviour, including temperature and strain rate effects, and the biaxial stress–strain response of the sheet are considered. A physically-based hardening model according to Bergström is used. This model incorporates the influence of the temperature and strain rate on the flow stress and on the hardening rate based on dynamic recovery. For deformations at constant temperature and strain rate, the Bergström model reduces to the well known Voce hardening model. The Bergström/Voce models can be fitted quite well to the results of monotonic tensile tests of an AA 5754-O alloy. The biaxial stress–strain response of the material is experimentally determined by uniaxial, plane strain, simple shear and equi-biaxial stress tests. It is demonstrated that the widely used Hill ’48 yield locus is inappropriate for simulation of deformation of aluminium. The low Rvalues for aluminium lead to a significant underestimation of the equi-biaxial yield stress. In the simulation of the deep drawing of a cylindrical cup this results in a much too thin bottom of the cup. The Vegter yield criterion is sufficiently flexible to accurately represent the shape of the yield locus and the anisotropy. 1

KW - Warm forming

KW - Aluminium

KW - Finite elements

KW - Material model

M3 - Conference contribution

SN - 84-9599922-6

BT - 7th International Conference on Computational Plasticity, COMPLAS VII

A2 - Onate, E.

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van den Boogaard AH, Bolt PJ. A material model for warm forming of aluminium sheet. In Onate E, Owen DRJ, editors, 7th International Conference on Computational Plasticity, COMPLAS VII. Barcelona: CIMNE Barcelona. 2003