Plasticity-damage model for concrete under cyclic multiaxial loading

A model that combines plasticity and damage mechanics is developed to assess both multiaxial monotonic and cyclic behavior of concrete. The model adopts a bounding surface concept and combines plastic deformation with the deformation due to damage. Plastic strain components are calculated by using the plastic modulus that is a function of the distance from the current stress point to the bounding surface along the deviatoric stress direction S o. Similarly, damage growth rate is obtained by the hardening modulus, which is a function of the distance just defined. The hardening behavior of concrete is assumed herein to be controlled by both damage and plasticity, while the strain-softening regime is controlled by damage processes only. The simultaneous use of the plasticity surface and the damage surface, leads to a constitutive model that accounts for the essential features of concrete such as pressure sensitivity, shear compaction-dilatancy, stiffness degradation, and softening behavior. © ASCE.