Finite element modelling of large radius bending operation

The finite element method is the default choice for the prediction of complex forming processes. In this work, this method is applied to the prediction of large radius air bending of high-strength steels. Three distinct formulations are used for the prediction: plane, shell, and solid. Appropriate mesh parameters and material implementation are used in order to obtain high prediction accuracy and to minimize the calculation time. A new law for the approximation of the hardening behavior of high-strength steels is introduced and further used for the minimization of the prediction error. Contact points position, springback, bending force and bend allowance are used for the comparison between experimental and simulation data. Obtained results show that the plane model is not a suitable option for the modeling of large radius air bending, due to an instable behavior with respect to the number of elements through the thickness. Shell and solid formulations, however, provide high accuracy prediction for the considered bending characteristics with comparable predictive quality.