Modeling the dynamic fracture of concrete — A robust, efficient, and accurate mesoscale description

Dynamic loading of concrete often leads to excessive cracking and fragmentation. Since these processes are massively influenced by the underlying heterogeneity of the material, discrete modeling of the lower-scale features strongly improves the simulation results. At the same time, the computational effort is greatly increased. We therefore propose here a mesomechanical simulation approach which is efficient in terms of model generation and computational efforts even for large 3d models. Furthermore, it is robust by limiting the application of computationally less efficient cohesive zone elements to the weak transition boundary between matrix and inclusions. Intermatrix failure is considered by a smeared crack approach and element removal after a certain crack opening has been reached. We apply an improved version of the widely used RHT concrete model, which is enhanced with a principal stress criterion. The resulting approach leads to an accurate replication of experiments in terms of crack propagation and stress wave induced dynamic fragmentation.