Semi-empirical calculation method for prediction of Forming Limit Curves based on mechanical properties

For characterisation purposes of sheet metal forming processes concerning feasibility of material mainly the Forming Limit Curve (FLC) is commonly used. This failure model can either be measured experimentally or can be predicted by using semi-empirical approaches. These mathematical approaches mainly are validated for Mild Steels. However, prediction of FLCs for modern High Strength Steels or Aluminium sheet alloys is not possible with acceptable accuracy today. This is why this contribution deals with a new semi-empirical approach for FLC prediction, which is valid for all sheet metal materials used in car body production. This approach uses a correlation of mechanical properties of uniaxial tensile test an experimentally determined limit strains.