Volume 105, Issue 2 e202401219
REVIEW

Selected issues in the upper bound theorem of plasticity

Sergei Alexandrov

Sergei Alexandrov

Laboratory for Technological Processes, Ishlinsky Institute for Problems in Mechanics RAS, Moscow, Russia

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Elena Lyamina

Elena Lyamina

Laboratory for Technological Processes, Ishlinsky Institute for Problems in Mechanics RAS, Moscow, Russia

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Yeau-Ren Jeng

Corresponding Author

Yeau-Ren Jeng

Academy of Innovative Semiconductor and Sustainable Manufacturing, National Cheng Kung University, Tainan, Taiwan

Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan

Correspondence

Yeau-Ren Jeng, Department of Biomedical Engineering, National Cheng Kung University, No. 1, University Road, East District, Tainan 70101, Taiwan.

Email: [email protected]

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First published: 24 February 2025

Abstract

The paper reviews the upper bound theorem in rigid plasticity, emphasizing its application to analyzing and designing metal forming processes. Two formulations of the theorem are considered. The peculiarities in applying the theorem to non-stationary and stationary processes are discussed. Special attention is devoted to friction boundary conditions. General methods of constructing trial velocity fields are presented. On the other hand, routine upper bound solutions based on the von Mises yield criterion are not reviewed, though their applied significance is not questionable. The article ends with a simple numerical example that illustrates all qualitative features of the theorem considered.

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