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 prediction of forming limit curve (FLC) for aluminum sheet is studied. Due to importance of FLC in sheet metal forming, concentration on effective parameters must be considered exactly in order to have better theoretical prediction comparing experimental results. Yield function is one of the factors which are improved by adding new coefficients that follows the behaviour of material with good approximation, so applying different yield functions can change shape and level of FLCs. In this study the yield criteria which are used in determination of forming limit curves, are Hill48, Hosford, BBC2008, Soare2008, Plunkett2008 and YLD2011. The YLD2011 yield function is more appropriate than the other yield function 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.