Bounds on the elastic threshold for problems of dissipative strain-gradient plasticity. (October 2020)

• Record Type: Journal Article
• Authors: Reddy, B.D.; Sysala, S.
• Is Part Of: Journal of the mechanics and physics of solids. Volume 143(2020)
• Publication Date: 2020-10
• Subjects: Dissipative strain-gradient plasticity -- Elastic threshold -- Duality -- Lower and upper bounds -- Penalization method -- Finite element method; Mechanics, Applied -- Periodicals; Solids -- Periodicals; Mechanics -- Periodicals; Mécanique appliquée -- Périodiques; Solides -- Périodiques; Mechanics, Applied; Solids; Periodicals; 531.05
• DOI: 10.1016/j.jmps.2020.104089
• Languages: English
• ISSNs: 0022-5096

Abstract

Abstract: This work is concerned with the purely dissipative version of a well-established model of rate-independent strain-gradient plasticity. In the conventional theory of plasticity the approach to determining plastic flow is local, and based on the stress distribution in the body. For the dissipative problem of strain-gradient plasticity such an approach is not valid as the yield function depends on microstresses that are not known in the elastic region. Instead, yield and plastic flow must be considered at the global level. This work addresses the problem of determining the elastic threshold by formulating primal and dual versions of the global problem and, motivated by techniques used in limit analysis for perfect plasticity, establishing conditions for lower and upper bounds to the threshold. The general approach is applied to two examples: of a plate under plane stress, and subjected to a prescribed displacement; and of a bar subjected to torsion.