Numerical Analysis of Cyclically Loaded Concrete Under Large Tensile Strains by the Plastic-Damage Model


Department of Civil and Environmental Engineering,Amirkabir University of Technology


Within the framework of plasticity-based constitutive laws, a plastic-damage model is
developed in a complete form for analysis of damaged structures under large tensile strains which is
suitable for concrete subjected to cyclic loadings. This is based on the plastic-damage model proposed
by Lee and Fenves, which utilizes two separate damage variables for tension and compression and also
a scalar degradation simulating damage on sti ness. Implementation of the model is coded for threedimensional
space in a special purpose nite element program to analyze the behavior of concrete subjected
to large tensile cracking, which is inevitable in plain concrete structures. In order to include large crack
opening/closing displacements in the model, the excessive increase in plastic strain causing unrealistic
results in cyclic behaviors is prevented when the tensile plastic-damage variable controlling the evolution
of tensile damage is larger than a critical value. To expedite the convergence rate for the overall equilibrium
iterations, the consistent algorithmic tangent sti ness tensor is also derived, in detail, for large cracking
states. The paper is completed with some numerical examples demonstrating the capability of the extended
model in reproducing the behavior of cyclically loaded plain concrete subjected to large tensile strains.