A. Assempour - Mechanical Engineering, Sharif University of Technology
M. Ganjiani - Mechanical Engineering, Sharif University of Technology

Forming Limit Diagrams are useful tools for evaluation of formability in the sheet metals. In this paper the effects of yield criteria on predictions of the right and left-hand sides of forming limit diagrams (FLDs) are investigated. In prediction of FLD, Hosford ۱۹۷۹, “Karafillis-Boyce” (K-B) and BBC۲۰۰۰ anisotropy yield functions have been applied. Whereas the prediction of FLD is based on the “Marciniak and Kuczynski” model, thus a numerical approach using the Newton-Raphson method has been used. Forming Limit Diagrams have been obtained for Al ۶۱۱۱-T۴ and AA۵XXX alloys and results have been compared with published experimental data. Results indicate that predictions of FLD are very sensitive to selection of yield criterion. Also it was found that the FLD of K-B yield function has a better agreement than that by other yield criteria.

Marciniak and Kuczynski Model, Karafillis and Boyce, Hosford ۱۹۷۹, BBC۲۰۰۰, Yield Function, Newton, Raphson Method