Modelling of Cohesive-Frictional Materials, Proc. CDM-2004, ed. by P.A.Vermeer et al.,
A.A.Balkema Publishers, Leiden, The Netherlands, pp. 323-337
NONLOCAL PLASTIC MODEL FOR COHESIVE-FRICTIONAL MATERIALS
Milan
Jirásek
Czech Technical University in Prague, Czech Republic
and
Peter Grassl
Swiss Federal Institute of
Technology at Lausanne, Switzerland
Abstract
Two classes of nonlocal models for softening materials with
nonassociated plastic flow are described and their localization
properties are analyzed. Models of the first class are based on
standard plasticity and use a hardening-softening law dependent on both
local and nonlocal cumulative plastic strain. Models of the second
class are based on combination of plasticity and damage mechanics and
use a damage evolution law dependent again on local and nonlocal
cumulative plastic strain. Conditions for continuous and discontinuous
bifurcations from a uniform state in an infinite medium are derived,
and the evolution of localized plastic zone is illustrated by simple
one- and two-dimensional examples.
Conclusions
We have shown that there is a close relationship between the critical
plastic modulus obtained by classical localization analysis based on
the acoustic tensor of a local model and the conditions of
bifurcation from a uniform state for the nonlocal extension of that
model based on nonlocal hardening law or nonlocal damage evolution law.
The results serve as a basis for the development of a regularized model
for concrete that can capture both tensile and compressive failure
modes.
If you wish to receive the complete paper, just send me an e-mail.
CVUT / 19 November 2004 / milan.jirasek@fsv.cvut.cz