A Visco-Damage-Plastic Model to Analyze the Impact Loading Response in Synthetic Rock

In the present study, a coupled damage-plastic constitutive model is proposed for capturing the rate-dependent response of intact rocks under dynamic loading conditions. A thermo-mechanically consistent continuum damage model is utilized for this study. The strain rate effect is introduced through viscoplasticity by enhancing the flow rule using the Perzyna type overstressed function. A fully implicit stress integration scheme is used for the numerical implementation of the model. The model response is calibrated based on the in-house dynamic experiments on synthetic rock specimens under Split Hopkinson Pressure Bar (SHPB). The model qualitatively predicts the variation in dynamic response, especially the peak stress and post-peak softening for different strain rates in the range of 50–150/s.