Finite element modeling of large radius bending operation

Abstract

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 minimise the calculation time. A new law for the approximation of the hardening behaviour of high-strength steels is introduced and further used for the minimisation 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 modelling of large radius air bending, due to an instable behaviour 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. [Submitted 21 August 2018; Accepted 27 January 2019]