Bulletin of the American Physical Society
2005 14th APS Topical Conference on Shock Compression of Condensed Matter
Sunday–Friday, July 31–August 5 2005; Baltimore, MD
Session U1: Energetic Materials VII |
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Chair: Richard Gustavsen, Los Alamos National Laboratory Room: Hyatt Regency Constellation B |
Thursday, August 4, 2005 3:00PM - 3:15PM |
U1.00001: Shock Intiation Experiments on PBX9501 Explosive at 150$^{\circ}$C for Ignition and Growth Modeling Kevin S. Vandersall, Craig M. Tarver, Frank Garcia, Paul A. Urtiew Shock initiation experiments on the explosive PBX9501 (95{\%} HMX, 2.5{\%} estane, and 2.5{\%} nitroplasticizer by weight) were performed at 150\r{ }C to obtain in-situ pressure gauge data and Ignition and Growth modeling parameters. A 100 mm diameter propellant driven gas gun was utilized to initiate the PBX9501 explosive with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments showed agreement with previously published data and Ignition and Growth modeling parameters were obtained with a good fit to the experimental data. This parameter set will allow accurate code predictions to be calculated for safety scenarios involving PBX9501 explosives at temperatures close to 150\r{ }C. This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. [Preview Abstract] |
Thursday, August 4, 2005 3:15PM - 3:30PM |
U1.00002: Evaluation of Aluminum Participation in the Development of Reactive Waves in Shock Compressed HMX Robert Pahl, Wayne Trott, Shane Snedigar, Jaime Castaneda A series of gas gun tests has been performed to examine contributions to energy release from micron-sized and nanometric aluminum powder added to sieved (212-300$\mu $m) HMX. In the absence of added metal, 4-mm-thick, low-density (64-68{\%} of theoretical maximum density) pressings of the sieved HMX respond to modest shock loading by developing distinctive reactive waves that exhibit both temporal and mesoscale spatial fluctuations. The complex transmitted wave profiles have been recorded using both single-point VISAR and a line-imaging optically recording velocity interferometer system. Parallel tests have been performed on samples containing 10{\%} (by mass) aluminum in two particle sizes: 2-$\mu $m and 123-nm mean particle diameter, respectively. Observed effects of these materials in reactive wave development will be discussed. [Preview Abstract] |
Thursday, August 4, 2005 3:30PM - 3:45PM |
U1.00003: Experimental Study of Grit Particle Enhancement in Non-Shock Ignition of PBX 9501 Paul Peterson, Richard Browning, Edward Roemer, Michael Oldenborg, Darla Thompson, Racci Deluca The drop weight impact test is the most commonly used configuration for evaluating sensitivity of explosives to non-shock ignition.~ Although developed 60 years ago and widely used both as a material compression test and as a test bed for understanding the ignition process itself, little is known about the flow mechanisms or involvement of grit particles as sensitizing agents.~ In this paper we present the results of a series of experiments designed to study the flow mechanisms and events leading up to ignition.~ The experimental configuration used involves two pellet sizes, 3 and 5 mm in diameter, tested in three conditions, (1) with smooth steel anvils, (2) with standard flint sandpaper, and (3) with shed grit particles loaded between the steel anvils and the pellet faces.~ Diagnostics include optical micrographs, and scanning electron micrographs.~ Un-reacted samples show a variety of morphologies, including what appear to be quenched reaction sites, even at very low drop heights.~ Quasi-static crushing experiments were also done to quantify load-time histories. [Preview Abstract] |
Thursday, August 4, 2005 3:45PM - 4:00PM |
U1.00004: Detonation and Shock Reactivity Properties of Explosives Containing RDX and Reduced Sensitivity RDX Gerrit Sutherland, John O'Connor, Eric Schlegel, Alan Zakraysek The detonation and shock reactivity properties of two monomodal research explosives were measured to assess how these properties change when different quality RDX is used. One explosive contained class 1 (coarse) RDX and HTPB binder; the other explosive contained reduced sensitivity (high quality) class 1 RDX (I-RDX) and HTPB binder. Experiments preformed included wave curvature, rate stick and flyer plate experiments. Wave curvature and rate stick experiments indicate that the reaction zone length is shorter for the explosive containing RDX. Our results show that decrement and wave curvature results are bounded by the results of Moulard and coworkers$^{1,2}$ for similar explosives containing fine and very coarse RDX particles. We will also present work of ongoing shock reactivity experiments. In these experiments, a flyer impacts an explosive sample containing multiple embedded pressure gauges. Analyses of the pressure gauge records allow us to determine shock reactivity trends for each explosive. $^{1}$Moulard, H., Kury, J.W., Delclos, A., Proceedings of Eighth Symposium (International) on Detonation, Albuquerque, NM, 1985, pg. 902-913. $^{2}$ Moulard, H., Proceedings of the Ninth Symposium (International) on Detonation, Portland, Oregon, 1989, pg. 18-24. [Preview Abstract] |
Thursday, August 4, 2005 4:00PM - 4:15PM |
U1.00005: The Effect of Precursor Shocks on Growth to Detonation of HMX based Explosives Susan Sorber, Ron Winter The response of the HMX-based explosive EDC37 to shock loading has been studied using electromagnetic particle-velocity gauges. One of the aims of the work was to determine the effect of a relatively weak pre-shock on the growth to detonation of a following, stronger, shock. Ideally this requires a comparison between the response of the sample when shocked by a simple sustained shock with that generated by a shock of the same amplitude, but preceded by a weaker pre-shock. Although our limited results do not allow a direct comparison, a normalisation technique has been developed which allows us to interpolate the growth-of-reaction curves for any chosen input shock. Comparison then allows the effective origin of the main shock in the pre-shock experiments, that is the plane at which the reaction starts to grow, to be located. It is found that this growth origin is located slightly before the plane at which the main, and the slower-moving pre-cursor shocks, coalescence. The distance between the effective growth origin of the main shock and the coalescence point depends on the stress of the pre-cursor shock. [Preview Abstract] |
Thursday, August 4, 2005 4:15PM - 4:30PM |
U1.00006: Lagrangian analysis of velocity-gauge data to determine reaction-rate histories in EDC37 Caroline Handley The Lagrangian analysis technique was applied to EDC37, an HMX- based explosive. The method was tested against an analytic model before being used to analyse particle-velocity-gauge data from two sustained-shock gas-gun experiments. This work provides evidence that the first stages of reaction in EDC37 are endothermic, as well as indicating that reaction-rate histories in explosives are bell-shaped. [Preview Abstract] |
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