Numerical study of compressive behavior of concrete at high strain rates

High strain rate unconfined compressional tests on concrete are simulated by a 3D discrete-element method. The laboratory data set was provided by three unconfined experiments on a split Hopkinson pressure bar apparatus at very high strain rates (350-700 s(-1)). This numerical method was chosen because it is well adapted to problems involving the characterization of fracturing and fragmentation in geomaterials. The simulations input data are the recorded experimental velocities, whereas the simulations output data are the computed forces that are compared with the experimental ones. The fit between the experimental and the numerical data is quite good. Based on this fit, it is shown that the strain rate dependency of the material strength can be explained by inertial effects.