Abstract: The influences of punch velocity to simulation time and results in automobile sheet metal forming simulation are studied at the view of sheet deforming and energy, a method is put forward to define the punch’s velocity basing on the ratio of kinetic energy versus total energy and the change of sheet deforming ratio. The definition method on punch velocity in forming simulation of the sheet metal can avoid grid aberration caused with inertia effects and reduce simulation time efficiently in computer simulation. As to Bao Gang ST16 material, if the ratio of kinetic energy versus total energy is ensured within less than 19%, and the change of sheet deforming ratio less than 3%, the punch velocity is elevated as high as possible, the simulation time will be efficiently shortened, and the simulation result will also satisfy engineering demands. The definition method on punch velocity in forming simulation of the sheet metal is applied to an oil-tank forming simulation and makes a good effect.

Key words: Energy, Explicit calculation, Punch velocity, Sheet forming