Study of sheet metal failure mechanisms based on stress-state conditions

Forming limit curves obtainable following the Swift, Hill, Marciniak-Kuczynski and Sing-Rao methods have been converted to stress states, and then compared with the plastic potential based on Hill's anisotropic yield criterion. Also, the influence of the variation of material properties such as anisotropy (R) and the hardening-exponent (n) on the prediction of the forming limit curve and the forming limit stress curve has been analysed critically, with appropriate comparisons with some published experimental data. The advantage of deriving a forming limit curve for a material directly from the material properties and the plastic potential is discussed. © 1997 Elsevier Science S.A.