Effect of asymmetry forming technology on longitude curvature radius of 3D curved part in continuous flexible rolling process

Continuous flexible rolling is a novel plastic forming process for 3D curved parts. In this work, asymmetry forming technology was firstly applied in continuous flexible rolling process, which can effectively compensate the lack of longitude bending deformation caused by work hardening. In the process of asymmetry forming technology, by changing the relative longitude elongation between the tensile surface and compressive surface of the sheet metal, the adjusting of longitudinal bending deformation is achieved. In this paper, the finite element model with different friction ratio was designed; the effect of asymmetry forming technology on longitude curvature radius of 3D curved parts was studied. As results demonstrate that: When the friction ratio between the upper (compressive) and lower (tensile) surface are 0.2:0.2, 0.2:0.15, 0.2:0.10, 0.2:0.05 and 0.2:0.2, 0.15:0.2, 0.10:0.2, 0.05:0.2 in turn, the corresponding longitude curvature radiuses of convex curved parts are 226 mm, 236 mm, 254 mm, 272 mm and 226 mm, 219 mm, 207 mm, 199 mm in turn. When the friction ratio between the upper (tensile) and lower (compressive) surface are 0.2:0.2, 0.2:0.16, 0.2:0.12, 0.2:0.08 and 0.2:0.2, 0.16:0.2, 0.12:0.2, 0.08:0.2 in turn, the corresponding longitude curvature radius of saddle curved parts are 330 mm, 321 mm, 315 mm, 306 mm and 330 mm, 339 mm, 345 mm, 350 mm in turn. The longitude bending deformation of sheet metal can be effectively adjusted in the asymmetry forming technology, so the feasibility of this technology is verified.