Predicting the formability of aluminum autobody sheet alloys

The tensile behavior of a series of Al alloys for automotive body panels was analyzed, and the data was used to predict the forming limit curve over a range of strain states. Using a modified form of the Voce work-hardening model, a Marciniak-Kuczinski simulation was constructed and used to predict the forming limit curve minimum (FLC₀). The comparison of predicted and measured forming limit curve data indicated that the model can be used to predict mechanical behavior under a state of plane strain using uniaxial tensile data. Correlations between the slope of the work-hardening curve and the FLC₀ provide an inexpensive method of comparing the formability of new alloy variants by thoroughly exploiting the data concealed in the full uniaxial tensile curve.