Numerical Biaxial Tensile Test of Aluminum Alloy Sheets Using Crystal Plasticity Model Implemented in Commercial FEM Software

To improve the accuracy of forming simulations for sheet metal, the use of material models calibrated by multiaxial material tests is essential. Adequate material models can be calibrated on the basis of the contours of equal plastic work obtained by multiaxial material tests. However, because the tests often require special experimental equipment, they are not widely used by the industry. This paper proposes a methodology for a numerical biaxial tensile test that uses ABAQUS, a popular commercial software package for finite element analysis. In numerical tests, an open-source user-defined material model (UMAT) is used to implement crystal plasticity models. In order to validate our methodology, we performed a numerical biaxial tensile test on a 6000-series aluminum alloy sheet, and the results were compared with those of biaxial tensile tests with a cruciform specimen. The results demonstrated that the proposed numerical biaxial tensile test provides a reasonable prediction of stress-strain curves and the contours of equal plastic work.