A Refined Model of Three-roller Elastoplastic Asymmetrical Pre-bending of Plate

The geometry of plate after edge pre-bending mode is Compared with that after roll-bending mode and the relationship among edge pre-bending angle, pre-bending edge length, and cylindrical desired radius is presented for a three-roller plate bender with bottom rollers adjustable horizontally. The analytical moment-curvature model and springback model for pure bending are established, assuming that the stress-strain relationship of material is linear, and the material is in plain strain and yields according to Mises yield criterion. The mathematical model for three-roller edge pre-bending of plate is developed considering the effect of pre-bending edge length, bottom roller radius, friction between plate and roller, etc. The plate tensile test and plate bending test are done and the numerical results agree well with the test data. The results are shown graphically and analyzed in the following aspects: (1) the error between numerical results and test data of top roller force; (2) the influence of bottom roller radius, relative curvature, and bending arc length on springback angle; (3) the relationship between springback ratio and edge pre-bending angle.