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Abstract. This work presents the results from dynamic penetration experiments in which long rod projectiles were launched into Ottawa sand at velocities ranging from 90 m/s to 350 m/s. A unique aspect of these experiments was that the sand targets were visually accessible, which allowed for the penetration event recorded using high-speed digital photography. The images were processed using two different correlation methods. In addition, stress measurements of the transmitted waveforms were simultaneously collected from a piezoelectric load cell that was buried in the sand at various locations relative to the shot line. The results indicate that impact results in two waves: one similar to a detached bow shock and one near the projectile that forms force chains. Grains are damaged and broken by the force chains which allows the projectile to penetrate the target.

Submitted for the SHOCK09 Meeting of The American Physical Society Development of the Small-Scale Shock Sensitivity Test (SSST) JOSHUA FELTS, HAROLD SANDUSKY, RICHARD GRANHOLM, IHDIV, NSWC-This effort is to develop a small-scale test to measure shock sensitivity that only needs a half gram sample at most. The test will screen new energetic compositions before the need for costly scale-up. The concept is to merge aspects of the Small-Scale Shock Reactivity Test (SSRT) developed at IHDIV, NSWC with that of gap tests. The SSRT measures the shock reactivity (explosiveness) of samples well-below critical diameter without requiring a transition to detonation. Gap tests are used to gage shock sensitivity of explosives, but require a sample size large enough for steady or near-steady detonation. The new test arrangement will combine the shock-attenuating gap before the sample and the air gap after the sample found in gap tests with the small sample size and high confinement of the SSRT. Our results for two plastic-bonded explosives formulated with either a regular or insensitive RDX confirm the difference in sensitivities observed in gap tests. More samples need to be tested to fully characterize the new test and to develop relations with shock sensitivity data from gap tests.

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