Bulletin of the American Physical Society
15th APS Topical Conference on Shock Compression of Condensed Matter
Volume 52, Number 8
Sunday–Friday, June 24–29, 2007; Kohala Coast, Hawaii
Session L6: Shock Initiation I |
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Chair: Robert E. Setchell, Sandia National Laboratories Room: Fairmont Orchid Hotel Promenade I/II |
Wednesday, June 27, 2007 8:00AM - 8:15AM |
L6.00001: Shock Initiation Experiments on PBX 9501 Explosive at Pressures Below 3 GPa with Associated Ignition and Growth Modeling Steven K. Chidester, Darla G. Thompson, Kevin S. Vandersall, Deanne J. Idar, Craig M. Tarver, Frank Garcia, Paul A. Urtiew Shock initiation experiments on the explosive PBX 9501 (95{\%} HMX, 2.5{\%} estane, and 2.5{\%} nitroplasticizer by weight) were performed at pressures below 3 GPa to obtain in-situ pressure gauge data, run-distance-to-detonation thresholds, and Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the PBX 9501 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 in the low-pressure regime (below 3 GPa) involving PBX 9501 explosive. 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] |
Wednesday, June 27, 2007 8:15AM - 8:30AM |
L6.00002: Shock Initiation Experiments on the HMX Based Explosives LX-07 and LX-10 with Associated Ignition and Growth Modeling Kevin S. Vandersall, Craig M. Tarver, Frank Garcia, Paul A. Urtiew, Steven K. Chidester Shock initiation experiments on the HMX based explosives LX-10 (95{\%} HMX, 5{\%} Viton by weight) and LX-07 (90{\%} HMX, 10{\%} Viton by weight) were performed to obtain in-situ pressure gauge data, run-distance-to-detonation thresholds, and Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the explosive samples with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments and prior experiments on another HMX based explosive LX-04 (85{\%} HMX, 15{\%} Viton by weight) will be shown, discussed, and compared as a function of the binder content. This parameter set will provide additional information to ensure accurate code predictions for safety scenarios involving HMX explosives with different percent binder content additions. 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] |
Wednesday, June 27, 2007 8:30AM - 8:45AM |
L6.00003: Extended run distance measurements of shock initiation in PBX 9502 Rick Gustavsen, Steve Sheffield, Rick Alcon We have completed a series shock initiation experiments on two lots of PBX 9502 (95 weight {\%} TATB, 5 weight {\%} Kel-F 800 binder). One PBX 9502 lot contained few fine particles (10 weight {\%} $<$ 20 microns) while the second lot contained many fines (38 weight {\%} $<$ 20 microns). Large, 71 mm diameter PBX 9502 samples were used and input pressures were 7.5 -- 8.5 GPa resulting in run distances to detonation of 25 -- 35 mm. These results extend previous work [J. Appl. Phys. 99, 114907 (2006)] in which we used 43 mm diameter samples, input pressures $>$ 10.5 GPa, and measured run distances $<$ 15 mm. Buildup to detonation was measured using embedded magnetic particle velocity gauges. An unusual feature of the work was the use of metallic impactors (316 stainless steel) in combination with magnetic gauges. It has previously been assumed that conducting impactors would badly perturb the magnetic gauge measurements; however, we observed no ill effects other than a nearly constant baseline shift of $\approx $ 10{\%}. Results include reaction rates at the impact surface and distance to detonation vs. initial pressure. No lot to lot differences in initiation behavior were observed. [Preview Abstract] |
Wednesday, June 27, 2007 8:45AM - 9:00AM |
L6.00004: Shock Reactivity of Non-Porous Mixtures of Manganese and Sulfur Francois-Xavier Jette, Samuel Goroshin, Andrew Higgins Stoichiometric mixtures of manganese powder and sulfur were melt-cast into solid pellets in order to study the mechanism of shock-enhanced reactivity in non-porous heterogeneous mixtures. This mixture was selected due to the large exothermic heat release of the manganese-sulfur reaction (214 kJ/mol), which causes the reaction to be self-sustaining once initiated. The test samples were placed in planar recovery ampoules and a strong shock was delivered via the detonation of a charge of amine-sensitized nitromethane. Various shock strengths were achieved by placing different thicknesses of PMMA attenuator between the explosive charge and the ampoule. The results confirmed that shock-induced reactions can be produced in the absence of porosity. Indeed, the critical shock pressure that caused ignition of the mixture in the ampoule was found to be in the range 2.2 - 3.8 GPa (pressures were estimated using LS-DYNA simulations). In the cases where the shock was too weak to cause ignition in the ampoule, the sample was extracted and its ignition temperature was determined using a differential thermal analyzer. [Preview Abstract] |
Wednesday, June 27, 2007 9:00AM - 9:15AM |
L6.00005: Time-Resolved Temperature Measurements of Shock Initiation in a Manganese-Sulfur Mixture Francois-Xavier Jette, Samuel Goroshin, Andrew Higgins Previous tests carried out in planar recovery capsules showed that strong (3-8 GPa) shock waves, generated by a charge of amine-sensitized nitromethane and attenuated by a PMMA layer, can initiate reactions in non-porous stoichiometric mixtures of manganese and sulfur. The current study focused on the onset of these reactions using time-resolved temperature measurements. A photomultiplier-based two-color pyrometer was used to record sample temperatures shortly after the passage of the shock while a thermocouple was used to record temperatures over longer time scales. An experimental complication encountered when studying shock-induced reactions in porous energetic materials using pyrometry, i.e. intense light due to large localized heating, can be mostly eliminated if a non-porous sample is studied. Further, in order to increase the reliability of the pyrometry results, the reactive test mixture (Mn+S) was chosen to have a high heat of reaction (214 kJ/mol) and thus a high reaction temperature, and baseline tests were performed with inert melt-cast mixtures of WS2 and sulfur. [Preview Abstract] |
Wednesday, June 27, 2007 9:15AM - 9:30AM |
L6.00006: ABSTRACT WITHDRAWN |
Wednesday, June 27, 2007 9:30AM - 9:45AM |
L6.00007: Observations of shock-induced partial reactions in high explosive Shiro Kubota, Yuji Ogata, Yuji Wada, Tei Saburi, Kunihito Nagayama The high speed photography, pressure measurements and numerical simulation of gap test of the high explosive have been carried out. The height of donor is 50 mm and acceptor is 40 mm with 26 mm inner diameter. When the gap length is 23 mm or large, the sympathetic detonation was not confirmed. Although the detonation does not occur, the gas expansion from the acceptor appears as the results of remarkable decomposition if the gap length approaches 23 mm. Those phenomena are very important on the point of view of the safety engineering. Finally, the parameters of initiation model which could reproduce the behaviors of high explosive around the critical condition were constructed. [Preview Abstract] |
Wednesday, June 27, 2007 9:45AM - 10:00AM |
L6.00008: Large Area and Short Pulsed Shock Initiation of A TATB/HMX Mixed Explosive Guiji Wang, Chengwei Sun, Jun Chen, Cangli Liu, Fuli Tan, Ning Zhang The large area and short pulsed shock initiation experiment on a plastic bonded mixed explosive of TATB(80{\%}) and HMX(15{\%}) has been performed with an electric gun where a mylar flyer of 19mm in diameter and 0.05$\sim $0.30mm in thickness is launched by an electrically exploding metallic bridge foil. The cylindrical explosive specimens (\textit{$\Phi $}16mm $\times $ 8mm in size) were initiated by the mylar flyers in thickness of 0.07$\sim $0.20mm, which induced shock pressure in specimen was of duration ranging 0.029$\sim $0.109$\mu $s. The experimental data were treated with the DRM(Delayed Robbins-Monro) procedure and to provide the threshold of shock pressure $P$ 13.73$\sim $5.23GPa. The shock initiation criterion of the explosive specimen is ($P$/GPa)$^{1.451}(\tau/\mu$s) = 1.2. Meanwhile the criterion in 100{\%} probability in the experiment is ($P$/GPa)$^{1.8}(\tau/\mu$s) = 2.63. In addition, the 30$^{\circ}$ wedged specimen was tested and the shock to detonation transition (SDT) process emerging on its inclined surface was diagnosed with a device consisting of multiple optical fiber probe, optoelectronic transducer and digital oscilloscope. The POP plot of the explosive has been gained from above SDT data. [Preview Abstract] |
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