Numerical solution of press amount of roller in flexible roller stretch forming

Utilizing the geometrical relationship of flexible roller stretch forming, the minimum press amount of roller and the corresponding minimum sheet elongation were calculated in the case of completer sheet-die joint. Noting that the elongations of a sheet in stretching direction are equal in different cross sections, the relationship of the maximum press amount and elongation was established. The forming processes of 08AL saddle-shaped and spherical parts were simulated by displacement loading method, and the result was compared with the analytical result of the force loading. It reveals that the distributions of both the equivalent stress and equivalent plastic strain of the curvature parts obtained by the displacement loading method are more uniform, and the forming quality more stable. The saddle-shaped and spherical parts were formed by a flexible roller stretch forming device, and the experiment shows that the numerical solution to displacement loading is feasible. The required displacement of each roller corresponding to different elongations can be quickly calculated with shorter force load debugging period. The proposed method could be applied to debugging the parameters of flexible roller stretch forming process.