Bulletin of the American Physical Society
16th APS Topical Conference on Shock Compression of Condensed Matter
Volume 54, Number 8
Sunday–Friday, June 28–July 3 2009; Nashville, Tennessee
Session E1: EM-4: Sensitivity and Initiation |
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Chair: Philip Church, QinetiQ Room: Tennessee Ballroom |
Monday, June 29, 2009 3:30PM - 3:45PM |
E1.00001: Non-Shock Initiation Model for Plastic Bonded Explosive PBXN-5 and Cast Explosive: Experimental Results Mark Anderson, Steven Todd, Terry Caipen, Charlie Jensen, Chance Hughs A \underline {d}a\underline {m}a\underline {g}e \underline {i}nitiated \underline {r}eaction (DMGIR) computational model is being developed for the CTH shock physics code to predict the response of an explosive to non-shock mechanical insults. The distinguishing feature of this model is the introduction of a damage variable, which relates the evolution of damage to the initiation of reaction in the explosive, and its growth to detonation. The DMGIR model is a complement to the History Variable Reactive Burn (HVRB) model embedded in the current CTH code. Specifically designed experiments are supporting the development, implementation, and validation of the DMGIR numerical approach. PBXN-5 was the initial explosive material used experimentally to develop the DMGIR model. This explosive represents a family of plastically bonded explosives with good mechanical strength and rigid body properties. The model has been extended to cast explosives represented by Composition B. Furthermore, the DMGIR model will extended to predict results of non-shock mechanical insults for moldable plastic explosives such as C4 and PrimaSheet. [Preview Abstract] |
Monday, June 29, 2009 3:45PM - 4:00PM |
E1.00002: Non-Shock Initiation Model for Plastic Bonded Explosive PBXN-5 and Cast Explosive Steven Todd, Terry Caipen, Dennis Grady, Mark Anderson A \underline {d}a\underline {m}a\underline {g}e \underline {i}nitiated \underline {r}eaction (DMGIR) computational model is being developed for the CTH shock physics code to predict the response of an explosive to non-shock mechanical insults. The distinguishing feature of this model is the introduction of a damage variable, which relates the evolution of damage to the initiation of reaction in the explosive, and its growth to detonation. The DMGIR model is a complement to the History Variable Reactive Burn (HVRB) model embedded in the current CTH code. Specifically designed experiments are supporting the development, implementation, and validation of the DMGIR numerical approach. PBXN-5 was the initial explosive material used experimentally to develop the DMGIR model. This explosive represents a family of plastically bonded explosives with good mechanical strength and rigid body properties. The model has been extended to cast explosives represented by Composition B. Furthermore, the DMGIR model will extended to predict results of non-shock mechanical insults for moldable plastic explosives such as C4 and PrimaSheet. [Preview Abstract] |
Monday, June 29, 2009 4:00PM - 4:15PM |
E1.00003: Autocatalytic Decomposition Mechanisms in Energetic Molecular Crystals Maija Kuklja, Sergey Rashkeev Atomic scale mechanisms of the initiation of chemical processes in energetic molecular crystals, which lead to the decomposition and ultimately to an explosive chain reaction, are still far from being understood. In this work, we investigate the onset of the initiation processes in two high explosive crystals - diamino-dinitroethylene (DADNE) and triamino- trinitrobenzene (TATB). We found that an autocatalytic decomposition mechanism is likely to take place in DADNE crystal that consists of corrugated, dashboard-shaped molecular layers. The presence of a dissociated NO2 group in the interstitial space between two layers induces a significant shear-strain between these layers, which, in turn, facilitates the further dissociation of NO2 groups from surrounding molecules through lowering the C-NO2 decomposition barrier. Unlike this, in TATB (that consists of flat, graphite-like molecular layers), an interstitial NO2 group positioned between two layers tends to produce a tensile stress (rather than a shear-strain), which leads to local molecular disorder in these layers without any significant modification of the C-NO2 decomposition barrier. The observed differences between the two materials are discussed in terms of their structural, electronic, and chemical properties. [Preview Abstract] |
Monday, June 29, 2009 4:15PM - 4:30PM |
E1.00004: Modeling of large scale and expanded large scale gap tests using the CTH hydrocode Gerrit Sutherland CTH calculations are performed to calculate the shock and particle velocities in the Plexiglas (PMMA) gap of large and expanded scale gap tests to determine which PMMA and Pentolite material models best replicate measured calibration data. This effort is in support of simulations in which the reactive response of the test explosive is calculated. A gap test consists of a Pentolite donor explosive charge that drives a shock wave into a PMMA attenuator or gap and then into a test explosive acceptor charge. A thicker attenuator will mean that less pressure and energy is put into the explosive. The greater the PMMA gap, the more sensitive the test explosive. To model the response of the test explosive, the simulations must first accurately determine the magnitude and shape of the shock wave driven into the gap by the donor explosive and the subsequent shock attenuation in the PMMA gap. Material models looked at include a tabular Pentolite equation of state generated by the PANDA thermo chemical code, viscoelastic models for PMMA and pressure dependent strength models for PMMA. [Preview Abstract] |
Monday, June 29, 2009 4:30PM - 4:45PM |
E1.00005: Explosive Train Scale Safety Testing of Candidate Booster Materials Andrew Stoodley, Mark Wright, Gareth Flegg, Tracey Vine A concern for initiation train design is that the use of relatively sensitive explosives to initiate an IHE could degrade its inherent safety properties. In order to understand the effect of a more sensitive explosive on an IHE, it is important to characterise the candidate explosive train materials as they would be utilised. To support the safety assessment of candidate booster explosives, a collaboration was established to evaluate the response of various formulations of interest (UF-TATB, LLM- 105, FOX-7, HMX and TATB) in the Explosive Train Scale Safety tests developed by QinetiQ. This report describes the three experimental configurations (slow and fast cook-off and shock sensitivity) and the results for the aforementioned materials. All of the materials displayed good safety characteristics in the fast cook-off, resulting in low order deflagrations. The TATB based, LLM-105 and most of the HMX based materials also displayed a similar response in the slow cook-off tests, yielding a low order event. The shock sensitivity experiments ranked the materials in the expected order, with UF-TATB yielding the least sensitive result recorded in the XTSS tests to date. [Preview Abstract] |
Monday, June 29, 2009 4:45PM - 5:00PM |
E1.00006: ABSTRACT WITHDRAWN |
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