International Journal of
Solids and Structures, 43 (2006), 7166-7196.
DAMAGE-PLASTIC MODEL FOR CONCRETE FAILURE
Peter
Grassl
University of Glasgow, Scotland
and
Milan
Jirásek
Czech Technical University in
Prague,
Czech Republic
Abstract
The present paper deals with the combination of plasticity and damage
applied to modeling of concrete failure. First, the local uniqueness
conditions of two types of combinations of stress-based plasticity and
strain-driven scalar damage are studied. Then a triaxial damage-plastic
model for the failure of concrete is presented. The plasticity part is
based on the effective stress and the damage model is driven by the
plastic strain. The implementation of the model in the form of a fully
implicit integration scheme is discussed and the corresponding
algorithmic stiffness matrix is derived. The constitutive response is
compared to a wide range of experimental results. Finally, the model is
applied to the structural analysis of reinforced concrete columns. A
regularized version of this model with weighted spatial averaging of
the damage-driving variable is published in a separate
paper.
Conclusions
The present study on the combination of stress-based plasticity and
isotropic damage for modeling concrete failure has led to the following
conclusions:
- For damage-plastic models with the plastic part based on the
effective stress, local uniqueness is always guaranteed (provided that
it is guaranteed for the plastic part only). This is not always the
case for models with the plastic part based on the nominal stress.
- The combination of plasticity based on the effective stress and
isotropic damage driven by the plastic strain has been shown to be
suitable for predicting the failure of concrete in a wide range of
loading cases from uniaxial tension to triaxial compression.
- The damage-plastic model can partially capture the reduction of
shear stiffness due to previous compressive loading.
- The model is thermodynamically consistent and the algorithmic
stiffness matrix is available.
- The model is suitable for three-dimensional structural
applications and seems to predict reasonably well the response of
reinforced concrete columns under eccentric compression.
If you wish to receive the complete paper, just send me an e-mail.
CVUT / 13 October 2006 / milan.jirasek@fsv.cvut.cz