Effect of Different Yield Functions on Computations of Forming Limit Curves For Aluminum Alloy Sheets

In this article, the effect of different yield functions on the prediction of forming limit diagram (fld) for the aluminum sheet is studied. due to the importance of fld in sheet metal forming, concentration on effective parameters must be considered precisely to have better theoretical prediction comparing experimental results. yield function is one of the factors that can be improved by adding new coefficients and consequently follows the behaviour of material with good approximation. therefor applying different yield functions can change shape and level of flds. in this study the yield criteria which are used in the determination of forming limit curves, are hill48, hosford, bbc2008, soare2008, plunkett2008 and yld2011. the yld2011 yield function is more appropriate than the other yield functions for prediction of the fld of aluminum alloy. the well- known marciniak-kuczynski (m-k) theory and voce hardening law have also been used. to verify the numerical results, the obtained results have been compared with available experimental data.