Multi-level modelling of mechanical anisotropy of commercial pure aluminium plate: Crystal plasticity models, advanced yield functions and parameter identification. (March 2015)

• Record Type: Journal Article
• Authors: Zhang, K.; Holmedal, B.; Hopperstad, O.S.; Dumoulin, S.; Gawad, J.; Van Bael, A.; Van Houtte, P.
• Is Part Of: International journal of plasticity. Volume 66(2015:Mar.)
• Page Start: 3
• Page End: 30
• Publication Date: 2015-03
• Subjects: A. Yield condition -- B. Crystal plasticity -- B. Anisotropic material -- C. Analytic functions -- Multi-level modelling; Plasticity -- Periodicals; Plasticité -- Périodiques; Plasticity; Periodicals; 620.11233
• DOI: 10.1016/j.ijplas.2014.02.003
• Languages: English
• ISSNs: 0749-6419

Abstract

Abstract: The mechanical anisotropy of an AA1050 aluminium plate is studied by the use of five crystal plasticity models and two advanced yield functions. In-plane uniaxial tension properties of the plate were predicted by the full-constraint Taylor model, the advanced Lamel model (Van Houtte et al., 2005) and a modified version of this model (Mánik and Holmedal, 2013), the viscoplastic self-consistent model and a crystal plasticity finite element method (CPFEM). Results are compared with data from tensile tests at every 15° from the rolling direction (RD) to the transverse direction (TD) in the plate. Furthermore, all the models, except CPFEM, were used to provide stress points in the five-dimensional deviatoric stress space at yielding for 201 plastic strain-rate directions. The Facet yield surface was calibrated using these 201 stress points and compared to in-plane yield loci and the planar anisotropy which were calculated by the crystal plasticity models. The anisotropic yield function Yld2004-18p (Barlat et al., 2005) was calibrated by three methods: using uniaxial tension data, using the 201 virtual yield points in stress space, and using a combination of experimental data and virtual yield points (i.e. a hybrid method). Optimal yield-surface exponents were found for each of the crystal plasticity models, based on calibration to calculated stress points at yielding for a random texture, and used in the latter two calibration methods. It is found that the last hybrid calibration method can capture the experimental results and at the same time ensure a good fit to the anisotropy in the full stress space predicted by the crystal plasticity models.