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Visualization and penetration by Tennessee

The stress-strain relationship of particulate/granular materials is complex and depends on the initial state of packing, past stress history, and the applied stress path (compression, shear, extension, or its combination). The deformation behavior is largely governed by its mesoscale corresponding to individual and a small group of particles, their connectivity represented by force chains, potential for particle breakage governed by the morphology, local void size distribution, and degree for fluid saturation. Recent advanced experimental characterization techniques for crystalline solids using advanced photon and neutron sources offer much potential to describe the mesoscale behavior quantitatively to realize the potential of predictive material science for granular materials. In the most simplistic form, one can assume that the metallic samples (crystalline metals or amorphous glasses) are a special form of granular media having very small pore space, thus demonstrating the broader impact of such research.

Comparative measurements using an advanced microfocus-based X-ray system, and in parallel, using a high-resolution neutron imaging setup provide now information both on solid (particle phase) and pore air and pore water phase clearly. The water phase information is coming from the neutron image only, and sand and air phase is coming from the X-ray image after images were registered.

High-resolution neutron image of sand target prior to impact

Active Investigator 

Dayakar Penumadu [link]