Examining explosives handling sensitivity of trinitrotoluene (TNT) with different particle sizes

Manner, Virginia W.; Tiemann, Clay G.; Yeager, John D.; Kay, Lisa M.; Lease, Nicholas; Cawkwell, Marc; Brown, Geoff W.; Anthony, Spencer P.; Montanari, Danielle

doi:10.1063/12.0001125

Cited by 9 publications

(20 citation statements)

References 10 publications

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“…The H 50 values were calculated using the Neyer D-Optimal method. The H 50 for TNT was obtained using samples prepared in ref . DAAF samples were obtained from LANL lot 500-45-36 .…”

Section: Resultsmentioning

confidence: 99%

“…This result implies that the changes to crystal morphology and internal defects that give rise to improved shock sensitivity play minor roles under the low strain rates of a drop-weight impact test. Similarly, a recent series of drop-weight tests using the Type 12 tool on recrystallized and melt-cast TNT samples with controlled particle size distributions showed no statistical differences in sensitivity as a function of particle shape or morphology …”

Section: Introductionmentioning

confidence: 91%

“…Similarly, a recent series of drop-weight tests using the Type 12 tool on recrystallized and melt-cast TNT samples with controlled particle size distributions showed no statistical differences in sensitivity as a function of particle shape or morphology. 32 Based on the mapping between H 50 and T* observed in ref 29, we have computed using quantum-based molecular dynamics simulations the rates at which condensed-phase secondary explosives containing only carbon, hydrogen, nitrogen, and oxygen will undergo thermal explosion. These simulations and the corresponding rates depend explicitly on both the chemical and structural properties of the energetic molecules as well as the entire spectrum of chemical reactions that take place during thermal explosion.…”

Section: ■ Introductionmentioning

confidence: 99%

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Ranking the Drop-Weight Impact Sensitivity of Common Explosives Using Arrhenius Chemical Rates Computed from Quantum Molecular Dynamics Simulations

Cawkwell

Manner

2019

J. Phys. Chem. A

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Drop-weight impact tests are used routinely to characterize the handling safety of explosives. Numerous studies have sought to connect various physical and chemical properties of the energetic molecules and materials to their measured impact sensitivities. Wenograd in the early 1960s demonstrated that there is a strong dependency of the drop-heights on the critical temperatures required for explosives to undergo prompt reactions. Reactive quantum molecular dynamics simulations with the lanl31 density functional tight binding model have been used to compute the delay time before the thermal explosion of the secondary explosives erythritol tetranitrate (ETN), pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine (HMX), trinitrotolune (TNT), and 3,3′-diamino-4,4′-azoxyfurazan (DAAF) as a function of the initial temperature and pressure. The delay time to explosion data are consistent with Arrhenius chemical kinetics, which is expected for thermally activated processes in materials and in accord with experimental measurements. The critical temperatures required for the materials to undergo prompt explosions display the same dependence on drop height as was observed by Wenograd. Hence, quantum-based reactive molecular dynamics simulations are potentially a tool for ranking the drop-weight impact sensitivity and handling safety of explosives.

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“…The H 50 values were calculated using the Neyer D-Optimal method. The H 50 for TNT was obtained using samples prepared in ref . DAAF samples were obtained from LANL lot 500-45-36 .…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ranking the Drop-Weight Impact Sensitivity of Common Explosives Using Arrhenius Chemical Rates Computed from Quantum Molecular Dynamics Simulations

Cawkwell

Manner

2019

J. Phys. Chem. A

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“…We used four TNT blendsnumbers 3, 6, 10, and 12from a previous work. 26 In addition to its low impact sensitivity, TNT typically exhibits higher variability during impact testing than PETN. Figure 4 shows that there is not as clear a separation in sound level for Go's and No-Go's, as there is for PETN (in Figure 3).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Sources of Variation in Drop-Weight Impact Sensitivity Testing of the Explosive Pentaerythritol Tetranitrate

Marrs

Manner

Burch

et al. 2021

Ind. Eng. Chem. Res.

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When new explosives are synthesized and developed, handling sensitivity must be measured in a consistent way to dictate safety protocols. Drop-weight impact tests, which represent explosive material sensitivity with the drop height required for a sample to react with 50% probability, are the most common method for understanding and quantifying explosive sensitivity. However, results from impact tests are influenced not only by the explosive material tested but also by the testing conditions and experimental setup. Examples of these testing conditions are the laboratory where the test was performed, the methods for choosing drop height levels and computing sensitivity, and whether grit paper was used to promote the initiation of reactions. We compile a historical data set with over 450 impact test results of the explosive standard pentaerythritol tetranitrate (PETN) from 1959 to 2020. We model the sensitivity of PETN as a function of the test laboratory, the test method, and the use of grit paper and find that all have a significant effect on the measured sensitivity of PETN. We validate the predictions from the fitted model with several new impact tests performed at Los Alamos National Laboratory.

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“…Despite multiple tests and investigations, the mesoscale processes that allow an ignition to propagate into a violent outcome are still not fully understood. While it has generally been agreed since the 1940’s that ignition under drop hammer conditions requires the formation of localized ignition sites, − followed by visco-plastic shear heating, − there is lack of consensus concerning the adiabatic heating of gas bubbles entrained in the explosive, the role of melting during the event, the effect of the material particle size, , and the presence or absence of grit during testing. − Furthermore, when dealing with less sensitive materials, e.g., 2,4,6-trinitrotoluene (TNT), the determination of a “go” can be more difficult because substantial material remains after the test despite an audible “go” . As a result, the test is recommended for ranking explosives within one laboratory and is not generally utilized for the in-depth analysis of the ignition and propagation behavior of explosives.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Ignition Sites for the Explosives 3,3′-Diamino-4,4′-azoxyfurazan (DAAF) and 1,3,5,7-Tetranitro-1,3,5,7-tetrazoctane (HMX) Using Crush Gun Impact Testing

et al. 2021

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The handling safety characteristics of energetic materials must be measured in order to ensure the safe transport and use of explosives. Drop-weight impact sensitivity measurements are one of the first standardized tests performed for energetics. They utilize a small amount of the explosive sample and a standard weight, which is dropped on the material from various heights to determine its sensitivity. While multiple laboratories have used the impact sensitivity test as an initial screening tool for explosive sensitivity for the past 60 years, variability exists due to the use of different instruments, different methods to determine the initiation, and the scatter commonly associated with less-sensitive explosives. For example, standard explosives such as 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX) initiate reliably and consistently on the drop-weight impact test, whereas insensitive explosives such as 3,3′-diamino-4,4′-azoxyfurazan (DAAF) exhibit variability in sound levels and the expended material. Herein we investigate the impact sensitivity of DAAF and HMX along with a more detailed investigation of ignition sites using a novel “crush gun” apparatus: a pneumatically powered drop-weight tower with advanced diagnostics, including high-speed visual and infrared cameras. Using this crush gun assembly, the ignition sites in HMX and DAAF were analyzed with respect to the effects of particle size and the presence of a source of grit. The formation of ignition sites was observed in both explosives; however, only HMX showed ignition sites that propagated to a deflagration at lower firing speeds. Finally, the presence of grit particles was shown to increase the occurrence of ignition sites in DAAF at lower firing speeds, though propagation to a full reaction was not observed on the time scale of the test. These results enable a better understanding of how ignition and propagation occurs during the impact testing of DAAF.

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Examining explosives handling sensitivity of trinitrotoluene (TNT) with different particle sizes

Cited by 9 publications

References 10 publications

Ranking the Drop-Weight Impact Sensitivity of Common Explosives Using Arrhenius Chemical Rates Computed from Quantum Molecular Dynamics Simulations

Ranking the Drop-Weight Impact Sensitivity of Common Explosives Using Arrhenius Chemical Rates Computed from Quantum Molecular Dynamics Simulations

Sources of Variation in Drop-Weight Impact Sensitivity Testing of the Explosive Pentaerythritol Tetranitrate

Analysis of Ignition Sites for the Explosives 3,3′-Diamino-4,4′-azoxyfurazan (DAAF) and 1,3,5,7-Tetranitro-1,3,5,7-tetrazoctane (HMX) Using Crush Gun Impact Testing

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