Anisotropic Hardening of HC420 Steel Sheet: Experiments and Analytical Modeling

Choosing the appropriate yield function is essential to precisely predicting the anisotropic hardening behavior of steel metals considering general loading directions. This research investigates the anisotropic hardening behavior of HC420 steel sheet by combining experimental and analytical modeling. Experiments are conducted for uniaxial tensile tests according to the three different directions and bulging tests to obtain hardening data. The experimental findings show that the loading direction affects the anisotropic behavior of HC420 steel’s strength and plastic deformation. The Chen-coupled quadratic and non-quadratic (Chen-CQN) approach is used to ensure the convexity of the HC420 steel. By comparing the Chen-CQN approach with the Yld2000-2d and Stoughton-Yoon’2009 yield functions, the Chen-CQN approach shows superiority in predicting the hardening behavior of the HC420 sheet, exhibiting a more straightforward numerical implementation and enhanced accuracy in yield stress predictions under different loading directions. Results from experimental hardening tests reveal that the Chen-CQN function precisely and flexibly characterizes the yield surface of HC420 steel, with a constant variation of within 2% from its predictions.