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 D2: Energetic Materials II |
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Chair: Douglas Tasker, Los Alamos National Laboratory Room: Hyatt Regency Constellation C |
Monday, August 1, 2005 1:30PM - 1:45PM |
D2.00001: Isentropic Compression of Nitroplastized Estane to 40 KBAR on the Sandia Z-Machine Rick Gustavsen, Dan Hooks, Bruce Orler, Dana Dattelbaum, Rick Alcon, Clint Hall, Mel Baer Nitroplasticized Estane is the plastic binder used to hold HMX grains together in the plastic bonded explosive PBX 9501. As part of an effort to characterize PBX 9501, we isentropically compressed the explosive and its constituents to $\sim $ 40 kbar on the Sandia Z-Machine. Nitroplasticized Estane binder samples were prepared as follows: A mixture of 49 wt. {\%} Estane$^{\mbox{{\textregistered}}}$5703 (BF Goodrich), 49 wt. {\%} Nitroplasticizer (a 50/50 eutectic mixture of bis(2,2-dinitropropyl)formal and bis(2,2 dinitropropyl)acetal), and 2 wt. {\%} Irganox$^{\mbox{{\textregistered}}}$ 1010 stabilizer was prepared as for PBX 9501 binder. Samples were compression molded into 0.1 -- 2 mm thick films at 110$^{o}$C. These were then mounted between 6061 Aluminum Z panels and PMMA or LiF VISAR widows. PMMA washers between the panel and window stabilized the binder thickness. Profiles of ramp waves transmitted through several sample thicknesses were measured and compared with a reference profile. A simple analysis of the results indicates that the binder behavior can be described using the Universal Liquid Hugoniot with an ambient sound speed of 1.7 km/s. [Preview Abstract] |
Monday, August 1, 2005 1:45PM - 2:00PM |
D2.00002: Isentropic Compression Experiments for Mesoscale Studies of Energetic Composites Melvin Baer, Clint Hall, Rick Gustavsen, Daniel Hooks, Steve Sheffield New experimental diagnostics and computational modeling provides an unprecedented means of greatly improving understanding of energetic material behavior at the mesoscale (grain or crystal level). Mesoscale simulations have revealed that mechanical loading produces wave fields are three-dimensional and unsteady and materials strongly interact in localized regions to control the sensitivity of initiation and sustained reaction. Key to this modeling is the determination of appropriate constitutive and EOS property data at extremely high stress-strain states. The Sandia Z accelerator and associated diagnostics provides new insight into the mechanical response of energetic composites via isentropic ramp-wave compression loading. In this presentation we describe a method to investigate ramp loading using Eulerian CTH shock physics analysis of the ICE experiments. This approach is applied to investigate the constituent response of PBX9501 subjected to $\sim $42 Kbar ramp with 300 ns duration. VISAR data reveals the averaged response of the composite material in comparison to the individual constituents including the effects of anisotropy of HMX crystals and the interactions of fine crystallites with the binder materials. [Preview Abstract] |
Monday, August 1, 2005 2:00PM - 2:15PM |
D2.00003: Ramp-wave Experiments to Measure Dispersiveness in Explosives James Kennedy, Blaine Asay, Kien-Yin Lee, David Oschwald, Keith Thomas, Bryan Henson, Laura Smilowitz Composite explosives such as PBX-9404\footnote{J. W. Nunziato, E. K. Walsh and J. E. Kennedy, \textit{Intl. J. Eng. Sci. }\textbf{\textit{16}}, 637, 1978.} and PBX-9501\footnote{J. J. Dick, A. R. Martinez and R. S. Hixson, \textit{Eleventh Intl. Detonation Symp}., p. 317, ONR 33300-5, 1998.} are known to disperse shock waves into ramp waves at stresses of 1.2 GPa or less. Thus a shock wave cannot propagate in those explosives at such low stresses. Ramp-wave experiments have been performed on PBX-9501 to determine the minimum stress level at which shocking up occurs. Gas-gun experiments involved impact of a projectile onto a fused-silica plate, which developed a ramp wave that was transmitted through the explosive sample. The shape of the wave exiting from the sample was measured with VISAR. The compression level at which the ramp steepens into a shock indicates the limit of the dispersive behavior. This is of interest particularly because the ramping-out behavior may reduce the vigor of response of an explosive to hazard circumstances that ignite deflagration, and thus forestall DDT. [Preview Abstract] |
Monday, August 1, 2005 2:15PM - 2:30PM |
D2.00004: A study of the effect of electrical energy input on detonation failure in wedges of the TATB based explosive EDC35. Darren Salisbury, Ron Winter, Lester Biddle Experiments have been conducted to investigate detonation failure in wedges of the Insensitive High Explosive EDC35 (95/5 TATB/Kel-F) with and without addition of external energy via an applied electrical field. The thickness of the plane wedges varied from 6mm to 1mm along a 100mm length with a height of 50mm. The wedge was initiated along a line at its thick edge. Streak photography was used to record the progression of the detonation wave from the thick end of the wedge and its subsequent failure towards the thin end of the wedge. Three experiments were conducted: 1) with no external electrical energy, 2) with input of 1.25 kJ from a 25kV pulsed power source applied to electrodes mounted in contact with the 50mm x 100mm faces of the wedge and 3) with input of 5kJ applied to the electrodes. Analysis of the streak records suggests that failure thickness was reduced. [Preview Abstract] |
Monday, August 1, 2005 2:30PM - 2:45PM |
D2.00005: Unreacted Hugoniots of Three Plastic Bonded Explosives A.M. Milne, N.K. Bourne, J.C.F. Millett There is a continuing interest in determining the detonation characteristics of loaded plastic-bonded explosives (PBXs). The UK licensing agency for explosives, DOSG, wishes to better understand the response of insensitive high explosives. This has required more detailed investigation of the transit of reaction from the unreacted state to products. The starting condition, before application of a kinetic scheme to describe reaction, is thus the unreacted Hugoniot for the material. In this work three PBXs, manufactured by BAE Landsystems, are investigated and modelled. All contain RDX in differing quantities in an HTPB binder. One of them contains aluminium. Two of the materials have the same weight percentage of filler and binder but differ in the grain size distribution entrained. The experimental Hugoniots are presented, and a composite equation of state is derived using an engineering model and shown to describe the measurements well. Further applications of the technique are described and future application is outlined. [Preview Abstract] |
Monday, August 1, 2005 2:45PM - 3:00PM |
D2.00006: The Shock Response and Microstructural Determination of an Inert Simulant S.A. MacDonald, N.K. Bourne, P.J. Withers, J.C.F. Millett, A.M. Milne The resolution of details of the microstructure in a polymer matrix composite has important applications in addressing safety issues in energetic materials. The generation of three-dimensional microstructure, using a non-invasive method of high resolution will advance knowledge in a range of fields. A series of inert composites have been studied with microstructure analogous to that of plastic bonded explosives (PBXs). The experimental aims of this study lay in several areas. Firstly, adequately defining the bulk morphology. Secondly in determining the geometry of defects that might lead to sites for accidental ignition within the material. Finally in demonstrating a direct linkage into the finite element prediction of mechanical response. The study included investigation of materials selected to firstly test the resolution limits of the X-ray microtomography equipment, but also since a parallel series of shock experiments (with associated modelling) was conducted. This work is the first step in providing a coordinated capability to understand accidental ignition within insensitive high explosives (IHEs). [Preview Abstract] |
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