Sheet metal anisotropy and optimal non-round blank design in high-speed multi-step forming of AA3104-H19 aluminium alloy can body

A new anisotropic yield function which accurately describes the complex anisotropy of aluminium alloy sheet metal is proposed in this paper. A non-linear least square method is used to determine the coefficients of this yield function based on the experimental results. By employing the back-Euler stress integration algorithm, this anisotropic constitutive model has been successfully implemented in commercial FEM software ABAQUS via user material subroutine UMAT to predict earing profile of AA3104-H19 deep-drawn and redrawn cups. Good agreement was found in the predicted earing profiles and those obtained in experimental deep-drawn and redrawn cups. The FE model was used in an iteration optimisation process to determine the optimal shape of non-round blanks to obtain the ear-free deep-redrawn cups, and non-round tooling was designed accordingly. Results showed the height of the ears is significantly reduced in the cup formed using this non-round blank compared with that of a conventional round blank which is important for smooth running of high-speed multi-step forming of aluminium can body.