ANALYSIS AND ASSESSMENT OF THE SPRING-BACK EFFECT OF STEEL SHEET METAL UNDER BENDING OPERATIONS

The accurate prediction of the spring-back effect is a major issue in the design of metal forming tools and operations. A bad prediction of the spring-back effect will cause geometrical and quality deviations from the designed part, together with the associated cost impacts. In this paper the analysis and evaluation of the spring-back effect of steel sheet metal under bending operations is presented. The aim of the work is twofold: 1) to assess how accurate the spring- back effect can be predicted by the finite element method (FEM) and theoretical approaches, and 2) to evaluate the effect of process parameters on the spring-back effect. To accomplish this, two case studies corresponding to L-bending and V-bending operations of steel sheet metal were selected. The spring-back effect for these case studies was then analysed and estimated using theoretical approaches and FEM. Several values of the process parameters were also considered in the evaluation. Finally, the results were compared with the experimental values and the prediction error for each approach was estimated. The results have suggested that the FEM approach can predict with accuracy the spring- back effect; however, the solution is very sensitive to the simulation and process parameters.