Direct Upper-Bound Solution and Finite Element Approach to Round-To-Square Drawing

Abstract
The paper presents a direct comparison between two modeling techniques of metal forming processes, in the present case wire drawing. The two methods have the same basic approach in using the Upper-Bound Theorem but the solution methods are fundamentally different. One method is a direct analytical solution requiring the knowledge of a kinematically admissible velocity field, the other method uses a finite element approach and calculation of the velocities at the nodes of the mesh. Both methods minimize the power required. The theoretical fundamentals of the two methods, the solution approaches and the results are presented and compared. The advantages and disadvantages of both methods are also analysed.