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In this work a series of experiments were carried out in which right-circular cylinders were launched into sand targets at velocities ranging from 70 to 150 m/s. The projectiles were launched along a view window in order to record the penetration event with high-speed photography. Stress measurements of the transmitted wave forms were simultaneously collected from a piezoelectric load cells buried in the sand. A particle image velocimetry (PIV) technique, which extracted information from the photographic images, was used to resolve transmitted wave profiles. A two wave structure was observed. The first wave, a compaction wave, moves at the bulk sound speed of the sand. The second is an attached fracture wave which is stationary relative to the projectile. Together these experiments further our understanding of high-speed granular penetration events. [ABSTRACT FROM AUTHOR]

Digital Speckle Radiography (DSR) is a technique allowing full field displacement maps in a plan within an opaque material to be determined. The displacements are determined by tracking the motions of small sub-sections of a deforming speckle pattern, produced by seeding an internal layer of lead and taking flash x-ray images. An improved DSR algorithm is discussed which can improve the often poor contrast in DSR images, such that the mean and variance of the speckle pattern is uniform. This considerably improves the correlation success relative to other similar algorithms for DSR experiments. A series of experiments involving the penetration of granular media by long-rod projectiles, and the improved correlation achieved using this new algorithm, are discussed. [ABSTRACT FROM AUTHOR]