Finite element analysis of spring-back characteristics on asymmetrical Z-shape parts in wiping Z-bending process

In recent years, the Z-bending process was rarely investigated, especially for the asymmetrical Z-shape bending process. This causes the lacks of understanding on bending mechanism and spring-back characteristics and results in the difficulty in die design and process control for the spring-back characteristics. In the present research, therefore, the wiping asymmetrical Z-bending process was examined by using the finite element method (FEM) and laboratory experiments. On the basis of the stress distribution analysis, the different of spring-back characteristics between the symmetrical and asymmetrical wiping Z-bending processes were investigated and clearly identified. In addition, the effects of working process parameters, including bend angle and tool radius on spring-back characteristics were investigated and clearly identified via the changes of stress distribution analysis as well. To verify the accuracy of the FEM-simulation results, the laboratory experiments were carried out. The experiments were carried out to validate the FEM simulation results. The FEM simulation results showed a good agreement with the experimental results with reference to the bend angles.