A simplified stress-based forming limit criterion for advanced high strength steel (AHSS)

International Deep Drawing Research Group 37th Annual Conference

Hance, B.M.^1 ; Huang, L.^1

United States Steel Corporation, 5850 New King Court, Troy

MI

48098, United States^1

关键词: Advanced high strength steel;    Experimental strains;    Forming limit curve;    Isotropic materials;    Linear relationships;    Metastable austenite;    Standard tension tests;    Work hardening behaviors;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/418/1/012037/pdf
DOI  :  10.1088/1757-899X/418/1/012037

来源: IOP

【 摘 要 】

A methodology for stress-based forming limit analysis has been developed for advanced high strength steel (AHSS). It was proposed that localized necking occurs when a critical normal stress condition is met. Using a basic, isotropic material model (von Mises, power law hardening), the criterion was applied to various 980 Class AHSS. In most cases the simplified criterion adequately described the experimental strain-based forming limit curve (FLC). For AHSS with substantial volume fractions of metastable austenite, a more sophisticated material model and/or an adapted failure criterion will be required. A strong linear relationship was found between the critical normal stress and the measured true stress at maximum load in tension. This empirical functionality applies over a large range of strength levels and may form the basis for a methodology by which FLCs may be estimated from standard tension tests. Finally, in the context of the proposed failure criterion, the effects of work hardening behavior on the "shape" of the strain-based FLC are explored.