A simulation-based prediction model of the restraining and normal force of draw-beads with a normalization method

This paper proposes a simulation-based prediction model to predict the restraining and normal force of drawbeads for the sheet metal forming process. A reliable prediction model is constructed for the equivalent drawbead by a modified DOE (Design of Experiment) method, which consists of the Box-Behnken design and a simplified full factorial design. To construct prediction models of draw-bead forces, draw-bead forces are first calculated by finite element analysis and confirmed by experiments followed by an approximation with second order regression equations in various design cases. To increase the accuracy of prediction models, normalization of draw-bead forces is conducted based on the effectiveness ratio of design variables in a regression analysis. The normalized draw-bead forces are then approximated by second order regression equations again. The accuracy of the prediction models constructed is verified by comparing the prediction results with the simulation results in the entire design space.