The coordinated deformation behavior in double-curved bending of pure titanium square/rectangular plate with multiple radius ratios

To extensively investigate the bi-directional bending behavior of sheet metal, double-curved bending experiments with radius ratios ranging from 1:1 to 6:1 were conducted based on TA3 titanium alloy square and rectangular sheets. In combination with finite element simulation, the evolution trend of the blank-die contact area and material flow rule were investigated. The results show that the radius combination and specimen shape both have a remarkable effect on the evolution of blank-die contact area and bending deformation mode. The evolution trend of the contact area is mainly dependent on the combination of the bending radius. Material flows from the centre to its surrounding area in a double curvature bending process. The greater the sheet bending radius ratio, the more apparent the flowing phenomenon is observed along the larger curvature direction. The finite element predicted results agree well with experimental results. The new findings in this paper not only expand the bending theoretical basis but also provide valuable reference for the double-curved parts.