Localization properties of strain-softening gradient plasticity models. Part I: Strain-gradient theories

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:46

Article

Jirasek, Milan¹  Rolshoven, Simon² 

[1] Czech Tech Univ, Dept Mech, Fac Civil Engn, Prague 16629, Czech Republic

[2] Hilti Aktiengesell, Bu Anchor, FL-9494 Schaan, Liechtenstein

关键词: Plasticity;    Strain-gradient models;    Nonlocal models;    Localization;    Softening;   

DOI  :  10.1016/j.ijsolstr.2008.12.016

来源: Elsevier

【 摘 要 】

This paper compares and evaluates strain-gradient extensions of the conventional plasticity theory. Attention is focused on the ability of individual formulations to act as localization limiters, i.e., to regularize the boundary value problem in the presence of softening and to prevent localization of plastic strain increments into a set of zero measure. To keep the presentation simple and to highlight the essential properties of the investigated models, only the static, rate-independent response in the small-strain range and in the one-dimensional setting is considered. These restrictions permit an analytical or semi-analytical treatment of the problem, while the basic characteristics of the solutions remain valid in the general, multi-dimensional case. The onset of localization is characterized as a bifurcation from a uniform state. The subsequent evolution of the localized process zone and of the shape of the strain pro. le is studied numerically. It is shown that certain pathologies, e.g., expansion of the plastic region accompanied by stress locking, may arise at later stages of localization. A similar analysis of models with gradients of internal variables is presented in a companion paper. (C) 2008 Elsevier Ltd. All rights reserved.

【 授权许可】

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