Simulation of concrete tensile failure under high loading rates using three-dimensional irregular lattice models

The material properties and failure modes of concrete depend on loading rate. For realistic simulation of concrete behavior under dynamic loading, it is essential that this rate dependency be considered. This paper proposes a three-dimensional lattice model—formed from rigid-body-spring elements—that incorporates the rate dependency of concrete strength, elastic modulus, and fracture energy. This is achieved by introducing a visco-elasto-plastic damage unit (formed from a combination of dashpots and Coulomb friction devices) into the rigid-body-spring elements. The results of simulations of elastic wave propagation and comparisons with experimental results reported in the literature validate the model for basic load patterns. Further, changes in the dynamic failure mode with differing loading rates, studied through simulation of the Split Hopkinson Pressure Bar test, are shown to be in agreement with experimental results obtained with respect to strength and fracture locations.