Reduction of Springback in V-Bending by a Reverse Bend Approach

The deformation mechanics of springback phenomenon in the V-bending of sheets was investigated by the finite element analysis. The axial stress distribution in the bent sheet was classified into three zones: the bending zone under the punch corner (zone I), unbending zone next to the bending zone (zone II), and the stress-free zone (zone III). The effects of the stress distributions in these three zones on the springback were examined in detail, and it was found that the stress distribution in zone 2 plays an important role in reducing the springback. A reverse bend approach was also proposed to reduce the springback in the V-bending process. The efficiency of the proposed approach was demonstrated by the finite element simulations, and was validated as well by the experiments conducted in the present study.