基于虚场法的铝合金各向异性屈服及硬化属性参数同步表征

Wrought aluminum alloy sheets are widely applied in aeronautic and astronautic industries thanks to their lightweight, high specific strength and high specific rigidity. They exhibit notable anisotropic plasticity due to the rolling fabrication process, which can significantly influence the mechanical behavior of the sheets, but also bring complexity to the analytical and numerical study of various forming processes. Currently, the conventional identification methods for the anisotropic yield and hardening properties usually involve multiple homogeneous tests and complex testing machines. They are also constrained by various limitations. In order to simplify the identification procedures, the full-field deformation measurement and the virtual fields method are coupled to identify the anisotropic yield and hardening constitutive parameters simultaneously from the same cyclic tension-compression tests on the bridge-like 2024 aluminum alloy sheet specimens. The results show that using the current test configuration the Hill1948 anisotropic yield parameters can be identified successfully with stable results when the two tension stages in the rolling and the transverse directions are combined and the multiple virtual fields constraints applied. As for the nonlinear kinematic hardening parameters, loading in a single material direction and a single set of virtual fields can guarantee a reliable identification result. The current work provides useful material information and a convenient identification tool for the aluminum sheet metal forming industry.