Stress wave-induced damage of sandstone for dry and wet conditions

We present meso-scale modeling of impact recovery experiments on sandstone using a hybrid Smooth Particle Hydrodynamic (SPH) and Discrete Element Method (DEM) approach. Each grain is represented with clusters of particles providing explicit representation of the grain/pore structure obtained from scanning electron microscope (SEM) or synthetic images. Modeling accounts for the influence of pore fluid and illustrates how grain/pore heterogeneity under dry and saturated States affects the evolution of grain damage. Results exhibit characteristics that are observed in impact recovery experiments. An increase in-grain damage is associated with an increase in stress level. Grains in dry samples are extremely and irregularly fragmented and show extensively reduced porosity, while less grain damage and higher porosity are observed in saturated samples. Pore fluid mitigates the interaction between grains, thus reducing fragmentation damage. This modeling approach in concert with experiments offers a unique way to understand dynamic compaction of brittle porous materials.