Investigation and Characterization of Dynamic Energy Absorbed by Shale Materials

This work investigates the dynamic energy absorbed by a shale material, which is generally classified as transversely isotropic, as a function of bedding orientations using experimental and analytical analysis. Experimentally, circular disks or Brazilian specimens of shale are tested under a high-impact diametral compression load in the split Hopkinson pressure bar, SHPB. Analytically, fundamentals of uniaxial stress and elastic wave propagation theory are utilized to derive the dynamic energy absorbed by the material. Thus, the experimental output data is used as input to the analytical damage model. The model was applied to two different orientations of shale related to the bedding directions. The experimental setup and the analytical analysis are presented. In general, results display a significant difference in the total absorbed energy and peak values that are required for exciting and increasing the cumulative micro and macro cracks in shale. The average strain and local energy results are presented and discussed.