Abstract: Two solving methods of Hill48 yield criterion based on stress anisotropy and deformation anisotropy, respectively, are analyzed in detail. The limitation of Hill48 yield criterion is discussed with presenting two kinds of expressions of the solving method of the anisotropic parameters. The uniaxial tensile tests of 5754O aluminum alloy sheet along different directions are carried out. With different solving methods of anisotropic parameters, the theoretical stress-strain curves and the deformation rule during the tension process along different directions are derived. By comparing the theoretical and experimental results, the effect of the solving method on the accuracy of the yield criterion is analyzed. Based on two kinds of solving methods of the parameters the finite element simulations of the deep drawing test of 5754O aluminum alloy sheet are carried out and the accuracy of different solving methods on describing the earing phenomenon is discussed. It is concluded that the solving problem based on stress anisotropy should be used for the research object mainly related to stress anisotropy, while that based on deformation anisotropy should be used for the research objecet mainly related to deformation anisotropy. This research has important reference value for the reasonable application of yield criterion on sheet metal forming.

Key words: Anisotropy, Plastic forming, Sheet metal, Yield criterion