Blank Shape Design Based on Inverse Finite Element Method Using Ideal Forming Theory and a Modified Kinematics Formulation

For stamping of sheet metals and converting them to specific product shapes without failure, the initial blanks should be correctly designed. Otherwise, final products will not be sound. So initial blank design is a critical step in stamping design procedure. In the present paper for calculating the total deformation gradient and its relation to each step’s deformation gradient tensor (F), a modified kinematics formulation will be introduced. This formulation has been used in connection with the ideal forming theory for predicting the initial blank shape of the specified products with defined blank thickness. In the ideal forming theory, each material element is prescribed to deform in a minimum plastic work path and ideal process is obtained when the deformations are most evenly distributed in the final products. The later has been assumed for developing a FEM code to predict the blank shape and size in one step, which has been applied for three different kinds of stampings, cylindrical, square and clover shape cups. The results show the capability of the new algorithm in designing the initial blank shape for stamping products.