Review of the Upper Bound Method for Application to Metal Forming Processes

In this paper, we review the upper bound method in plasticity with special reference to metal forming processes. We focus on the method itself, solution methods, and restrictions of the upper bound method. Particular upper bound solutions are not considered. The upper bound theorem is formulated using the work function, which is different from conventional proofs. This approach allows for a unified formulation for several types of rigid plastic materials. The solution methods include upper bound elemental techniques, streamline-based methods, and singular solutions. The major restrictions are related to stationary processes and friction laws. © 2022 by the authors.