Abstract To evaluate the formability of sheet metal, the forming limit diagram (FLD) has been widely utilized. However, obtaining an FLD experimentally is time-consuming and costly. Consequently, there has been an increasing demand for the development an appropriate plasticity model to assess the FLD. In this study, the Marciniak-Kuczyński (MK) theory was applied to a recently developed incremental elasto-visco-plastic self-consistent model to evaluate the FLD of AA6061-T6, and its validity was verified by comparing it with experimental results. The initial texture was characterized using an orientation distribution function (ODF) obtained from electron backscatter diffraction (EBSD) measurement. The parameters describing the hardening behavior were optimized based on uniaxial tensile and bulge test results. To experimentally obtain the FLD, Nakajima test was conducted using five specimens of different geometries, enabling the determination of forming limit strains under various strain paths.
Lee et al. (Mon,) studied this question.