Determination of the Forming Limit Stress Curve for Anisotropic Sheets

The aim of this study is to propose s calculation method based on Hill's yield criterium to determine the forming limit stress states for anisotropic sheets. First we determine experimentally the forming limit diagrams of a titanium sheet for various strain path shapes. From these diagrams, we calculate then the limit stress states. They are plotted on single curve of the plane σ xσ y. So this forming limit stress diagram is Independent of the strain path shape. Then we propose a reverse calculation to determine the forming limit diagrams for this limit stress curve whatever may be the strain paths. The calculated curves are in very good agreement with the experimental points.