SIMULATION OF SHEET METAL FORMING PROCESSES-RECENT DEVELOPMENTS AND LIMITATIONS

摘要

Formed metal parts frequently occur in many everyday items from automobiles to cooking utensils. Due to the high cost of production tooling and time delays if the tooling fails to perform properly during tryout, there is an increasing interest in the numerical modelling of the forming process to determine formability. Over the last two decades the rapid development of finite element (FE) technology has made a significant contribution to the sheet metal forming industry. During the product development cycle, the FE analysis codes are playing an important role from quick qualitative check at the conceptual level, followed by quantitative validation at the tryout phase up to the final process validation and tuning. Typically, the design parameters to be determined are process variables such as, holding forces, friction, drawbead restraining, material properties, or geometric parameters like blank cutting pattern, radii (die, punch corner, etc...). However, numerical simulations often achieve less than satisfactory accuracy due to unknown mechanisms, inaccurate input data and the limits of the capability of computers. This paper summarises the state of the art of simulation technology and emphasises the new developments in material models, tribology system, and the methods of increasing the capability of computers, such as parallel processing methods and meshing strategy.