Abstract:In the hydraulic bulge tests, dies with both circular and elliptical apertures were used. A recently proposed methodology was used to determine the equivalent stress-strain curves by bulging through elliptical dies. This methodology combines an analytical approach with the experimental data measured by an ARAMIS system. In the hydraulic bulge test using elliptical dies, as the die ellipticity ratio decreases, the equivalent stress-strain curves tend to move away from the curve obtained from bulging through circular die. The forming limit diagram in the range of positive minor strain of a DC04 sheet steel is also determined by using bulge test.

Key words: hydraulic bulge test; stress-strain curves; forming limit diagram