Numerical analysis of the bulge test in temperature for the EN AW 6061-T6 sheet

Abstract

The equibiaxial expansion test allows the evaluation of the mechanical behaviour of materials on a large strain range. In this context, a bulge test device was developed which enables a fast heating stage, a uniform heating of the specimen, and the control of the temperature during the expansion phase. Although during the test, the temperature is uniform at the pole of the cap, the contact with the tools imposes a gradient along its radius. Therefore, a thermo-mechanical model of the bulge test was built in order to improve knowledge about the influence of the temperature gradient in the evaluation of the hardening behaviour at the pole of the cap. Numerical simulations of the bulge test were performed considering both isothermal and anisothermal conditions. The anisothermal conditions considered reproduce the temperature gradient observed experimentally. This enables the analysis of the impact of the thermal gradient in the stress versus strain evolution at the pole of the cap and the comparison with experimental results.