Innovative measurement technique to determine equibiaxial flow curves of sheet metals using a modified Nakajima test

Since an inhomogeneous punch pressure distribution occurs in the Nakajima test, equibiaxial flow curves have been determined solely in the hydraulic bulge test so far. By using an innovative measurement technique, it is possible to determine both the punch pressure and strains that occur in the Nakajima test. In this paper, a calibration and realization strategy is presented that allows to determine accurate equibiaxial flow curves for sheet metal materials using a modified Nakajima test without inverse parameter identification. This setup is suitable to substitute the expensive and time-consuming hydraulic bulge test by a simple and common experimental setup.