Modeling of plain concrete structures based on an anisotropic damage formulation

In this contribution, a strain-based constitutive law for concrete within the framework of continuum damage mechanics is proposed. The model allows for the multi-axial simulation of predominantly tensile loaded plain concrete structures. A second-order integrity tensor is chosen as the internal damage variable to consider the phenomenon of load-induced anisotropy. The model is implemented in the finite element method. Hence, a fracture-energy based regularization approach is included to overcome the mesh-dependence of the computational results. The proposed model is applied to the simulation of well-known experiments with plain concrete specimens, which are often used to demonstrate the applicability of damage constitutive laws. In this context, attention is focused especially on problems regarding the accurate implementation of the complex loading and boundary conditions. Oversimplifications are discussed and proposals for a more realistic involvement of the test setups in finite element models are submitted.