MODELING AND OPTIMIZATION OF SPRINGBACK WITH CONTACT EVOLUTION IN SHEET METAL FORMING

Chen Lei  Yang Jichang  Chen Wei

(School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013)

Zhang Liwen

(School of Materials Science and Engineering, Dalian University of  Technology, Dalian 116023)

Abstract: Springback in sheet metal forming process is due to the elastic deformation of the part during unloading. The design optimization of springback in sheet metal forming process is to control the final shape of the workpiece. Accurate prediction of springback is essential for the design of tools used in sheet metal forming operations. The manufacturing process design difficulty is formulated to minimize the difference between the shape of the desired workpiece geometry and the final analysis result after elastic springback. A finite element model is used to predict springback with contact evolution between the sheet and dies. A relatively simple springback benchmark (unconstrained bending of NUMISHEET’02) is solved. Sensitivity analysis done using FEM demonstrated that the magnitude of springback and the overall accuracy are highly influenced by the integration points, element size and material model. A conventional optimization method combined with FEM is used to obtain optimum parameters that can predict springback more accurately than 90%. The solutions are validated with experimental data in the literature.

Key words: Springback  Unconstrained bending  FEM  Modeling  Optimization

CLC No: TG386.3

国家自然科学基金(50475125)和江苏省自然科学基金(BK2002009) 资助项目. Received 20040815, received in revised form 20050120