Numerical Determination of Sheet Metal Forming Limit Based on a New Combined Model of M-K Theory and Shear Localization Criterion

A combined forming limit model of M-K theory and shear localization criterion is proposed in this paper to study the formability of 6016-T4 Aluminum alloy sheet, with the sheet material modeled by the Yld2000-2d yield function and two isotropic hardening models. The forming limit curve (FLC) of the material can be predicted well using the M-K model in the right region, and using the shear localization criterion in the left region. The critical plane strain of the material was computed using the M-K model and then used to determine the shear localization criterion. In fact, the combined model takes advantage of both of these theories. As a consequence, the results obtained from the proposed combined necking model seem to agree satisfactorily with those of the experiments.