Multiple-scale Analysis of Impact Fracture

We present a multiple-scale approach for the analysis of tensile failure of concrete under impact loading. A phenomenological rate dependent constitutive model is applied at the macroscopic level. Viscosity terms are included to represent the strengthening effect associated with the microstructural moisture and inertial effects of micro-cracking. A partial length scale effect is extracted from mesoscopic analyses and linked to the viscosity terms in the macroscopic model. The kinetic law in the macroscopic and mesoscopic models controlling the strength increase is linked to physical processes at a microscopic level. Experimental results using the Split Hopkinson Bar test are reproduced with the multiple-scale model.