The effect of strain rate sensitivity on the prediction of the formability of advanced high strength steels

This paper analyzes the effect of strain rate sensitivity on the prediction of formability of advanced high-strength steels (AHSS). Three conventional dual-phase (DP) steels, 590DP, 980DP and 1180DP, and two third-generation AHSS grades with ultimate tensile strengths of 980 MPa and 1180 MPa are selected as reference materials. The onset of localized necking is simulated using the Marciniak-Kuczynski model, with the Yld2000-2d yield criterion defining the initial yield locus. The Swift strain-hardening power law, with and without strain rate sensitivity, is used to describe the material hardening behavior. A comparative analysis is carried out to assess the accuracy of forming limit predictions, with a particular focus on the influence of strain rate sensitivity. The results show that the Yld2000-2d yield criterion, combined with the Swift hardening law incorporating strain rate sensitivity, achieves the best agreement with experimental data. This study highlights the necessity of accounting for strain rate sensitivity in the Marciniak-Kuczynski model to improve the accuracy of forming limit predictions for advanced high-strength steels.