Springback Compensation Based on Finite Element for Multi-Point Forming in Shipbuilding

Abstract

Flame bending has been widely used for forming hull plates of marine vessels, Since it is difficult to estimated the amount of residual deformation after applying the flame heat, flame bending has been carried out by skilled workers without automatic facility. A mechanical bending such as multiple-piston pressing forming has been studied as an alternative to the flame bending. However, springback is a major problem in the press forming process. Present paper presents a combination of FEM (Finite Element Method) and springback compensation algorithm to calculate the compensated stroke of pressing points. In order to calculate the springback, the process is modeled by an elastic plastic material and shell elements. Combination of global scale factor and local scale factors is suggested to adjust the amount of strokes through an iterated numerical calculation. In each iteration, shape deviation between object surface and processed shape is minimized to reach the designed shape. The shape deviations due to springback are compensated using the residual shape estimated by FEM.