Numerical analysis of damage and failure behavior of concrete

The paper discusses an anisotropic continuum damage model for concrete and its numerical implementation into a finite element program to provide an efficient approach suitable for boundary-value problems analyzing nonlinear concrete behavior. The phenomenological continuum approach is based on kinematic description of damage. Irreversible deformation behavior as well as volume increase of material samples even under compression loading are simulated by a damage strain rate tensor. The elastic constitutive equations are affected by damage strain tensors modeling decrease of elastic material parameters. The numerical procedure is based on the damage predictor-elastic corrector technique and the corresponding consistent tangent modulus is presented. Different experiments have been performed and deformation fields are analyzed by digital image correlation technique. Numerical simulations of the experiments show good agreement of the results and elucidate stress and damage states in the specimens. They allow prediction of failure modes of the tested specimens agreeing well with photographs of fractured cylinders and cubes. They also demonstrate the efficiency and the applicability of the proposed continuum damage model.