Strain rate dependent hardening of DP600 sheet metal for large strains under in-plane biaxial loadings

Abstract

In this work, an in-plane biaxial tensile test of cruciform specimen is performed to identify the visco-plastic hardening behaviour of metallic sheets for both large strains and intermediate strain rates at room temperature. Firstly, an optimal shape of the specimen is suggested. Then, dynamic biaxial tensile tests are carried out for a dual phase DP600 steel sheet. Experimental forces on the two axes of the specimen are measured during the test and strains in the central area of the specimen are post-treated by means of Digital Image Correlation (DIC) technique. Finally, considering a Hill48 anisotropic yield criterion, two strain rate dependent hardening laws are identified thanks to an inverse procedure based on a Finite Element (FE) modelling of the biaxial tensile test and on the experimental data mentioned above. The identified biaxial flow curves are then compared with the ones from a classical uniaxial tensile test.