Preform optimal design of H-shaped forging based on bi-directional evolutionary structural optimization

Preform design is one of the most important aspects in forging process design. An automatic method of preform optimal design based on the bi-directional evolutionary structural optimization is presented in this paper. The complete filling of die cavity with less flash and uniform deformation of material are the goals of the preform optimal design. A new criterion of element addition/deletion is proposed. The new criterion is associated with objective functions. The technique of element information tracking and transferring is introduced and the variables can be transmitted from the final mesh of the forging to the background grid that represents the preform. The method of boundary smooth fitting of the preform using the B-Spline curve is given. The preform optimal design for an H-shaped forging is carried out to demonstrate the effectiveness of the proposed method. A near net-shape forming is achieved meanwhile the uniform deformation is obtained.