Determination of Stress-Strain Curves of Sheet Metals by Hydraulic Bulge Test

The paper is focused on the determination of the biaxial stress - strain curves by hydraulic bulging tests with circular die using a new methodology. This methodology is based on a modified version of Kruglov's formula for the calculation of the polar thickness that takes into account the non-uniformity of the strain distribution on the dome surface. In order to validate the methodology, the authors have performed both stepwise and continuous bulging experiments using the optical measurement system ARAMIS. The comparison with experimental data shows an improved accuracy of the modified Kruglov's formula.