Localization analysis of nonlocal models with damage-dependent nonlocal interaction

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:174

Article

Jirasek, Milan¹  Desmorat, Rodrigue² 

[1] Czech Tech Univ, Fac Civil Engn, Dept Mech, Thakurova 7, Prague 16629 6, Czech Republic

[2] Univ Paris Saclay, LMT, ENS Paris Saclay, CNRS, 61 Ave President Wilson, F-94235 Cachan, France

关键词: Damage mechanics;    Plasticity;    Strain localization;    Softening;    Nonlocal models;   

DOI  :  10.1016/j.ijsolstr.2019.06.011

来源: Elsevier

【 摘 要 】

This paper systematically evaluates (in the one-dimensional setting) the performance of a new type of integral nonlocal averaging scheme, initially motivated by the idea of internal time that reflects the reduction of the elastic wave speed in a damaged material. The formulation dealing with internal time is replaced by the equivalent concept of a modified spatial metric leading to a damage-dependent interaction distance. This modification has a favorable effect on the evolution of the active part of damage zone and leads to its gradual shrinking, which naturally describes the transition from a thin process zone to a fully localized crack. However, when a pure damage model (with no permanent strain) is considered, the resulting load-displacement diagrams exhibit dramatic snapbacks and excessively brittle behavior in the final stages of failure. The concept of damage-dependent interaction distances is therefore extended to damage-plastic models and damage models with inelastic (permanent) strain. It is shown that, for formulations that consider a part of the strain as irreversible, the overall stress-displacement response becomes realistic for quasi-brittle materials such as concrete, for which the diagram typically exhibits a long tail. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

Free