A simplified isotropic damage model for concrete under bi-axial stress states

This paper presents a concrete model that is capable of describing the response of concrete under bi-axial loading, with the features of simplicity and avoidance of convergence problems, often seen in plasticity based models. The proposed model incorporates the failure of concrete into a conventional continuum damage mechanics framework, where particular emphasises are placed on highlighting the different responses of concrete under tension and compression, as well as the different contributions of hydrostatic and deviatoric stress components on concrete damage. A weighted damage parameter and a damage multiplier are introduced to eliminate potential convergence problems and to reduce the effect of hydrostatic pressure on damage, respectively. Finally, several examples are provided and compared with experimental data.