Fracture energy based bi-dissipative damage model for concrete

An isotropic damage model for concrete is presented. The main features of the model are: limited number of constitutive parameters required; independent modelling of tension and compression behaviour by means of two damage variables and two separate activation criteria (bi-dissipative model); independent definition of tension and compression fracture energies by means of constitutive parameters which do not affect the pre-peak behaviour; consistent modelling of the unilateral effect upon transition from tension to compression. To overcome the problem of mesh dependence in the softening regime, the effectiveness of a fracture energy based regularisation strategy is shown and the conditions for its correct application are defined. Comparisons of numerical simulations with experimental tests reveal the good accuracy and the robustness of the proposed model.