Research On Numerical Simulation Method For Tube Hydroforming And Sheet Metal Hydraulic Drawing

The technology of tube hydroforming and sheet metal hydraulic drawing is rapid developed in recent decades. It becomes the main forming technology for most of the pipe and part of the complex sheet metal. It also lacks of sufficient experience as a new technology, and the forming process parameters such as pressure liquid, the axial supplements, the radial supplements and so on, is difficult to determine. To get the suitable process parameters, traditional methods is through large and repeated experiments, but cumbersome, not economic. This problem is mainly solved by the emergence of finite element method used in numerical simulation.This research is supported by NSF named as"The Independent Research of rapid Simulation and Optimal Process Design aiming at the Formability of Automobile Panel forming"and National 863 plans projects (No: 2006AA04Z140). An algorithm for tube hydroforming and sheet metal hydraulic drawing is recently presented which is based on the dynamical explicit method and BT element. And it is integrated into the software FASTAMP, which is developed by State Key Lab of Material Processing and Die & Mould Technology of Huazhong University of Science and Technology.A number of key technologies for dynamic explicit method in metal forming is in-depth study, including BT shell element from the mathematical model and the solutions about hourglass. The dynamic analysis explicit solution algorithm and the stability conditions are relatively simple introduced. Based on the dynamic explicit finite element methods and BT shell element, the algorithm of is presented. The liquid-pressure load curve, condition of contact between tube and mould, the axial supplements and the radial supplements in practice is focused on. The algorithm is integrated into the software FASTAMP. And the process of hydroforming on three-diameter shaft is explores. The precision of the algorithm are validated by compared with experimental result. Finally, to validate the practicability of the algorithm, the actual production of automobile tube is simulated, and the process parameters are optimized by the simulation result to improve the tube forming ability. Also some simple comparison with a similar algorithm is done.On the basis of the sheet metal stamping explicit method, the algorithm of sheet metal hydraulic drawing is presented. A number of key technologies: the identification of the scope of the liquid pressure influence, the distribution of fluid pressure, the binder holder force, the lubrication and contact between sheet metal and mould and so on. The algorithm is integrated into the software FASTAMP. The square box is simulated, and the accuracy of the algorithm is verified by compared with experimental data. Final the actual production of automobile panel, oil box is selected and simulated. Once again the algorithm accuracy and practicality is proved.