Impact-induced friction ignition of an explosive: Infrared observations and modeling

Perry, W. Lee; Gunderson, Jake Alfred; Balkey, M. M.; Dickson, Peter

doi:10.1063/1.3487932

Cited by 28 publications

(24 citation statements)

References 10 publications

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“…While other methods of initiation in energetic materials such as pore collapse [28,29] and frictional heating with grit [6,30,31] are also possible, shear banding appears to be dominant impact initiation mechanism for the AlFA composite system in this study. Through our simulations we have shown the shear bands to take on ring and crescent structures that compare well with the experimentally determined ignition locations and path of preferential spreading within the sample at the impact face.…”

Section: Modeling Results and Discussionmentioning

confidence: 97%

“…Examining the impact face itself requires an entirely different setup involving a transparent window that can act as a rigid anvil, while also allowing for the head-on impacts to be interrogated [5][6][7]. In previous work by Crouse et al [8,9], an aluminized fluorinated acrylate-based polymer composite (AlFA), reinforced with nano-sized particles, has been shown to be highly reactive over a large range of aluminum particle reinforcement levels.…”

Section: Introductionmentioning

confidence: 99%

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Impact Initiation of Reactive Aluminized Fluorinated Acrylic Nanocomposites

White

Crouse

Spowart

et al. 2016

J. dynamic behavior mater.

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The initiation of aluminized fluorinated acrylic (AlFA) nanocomposites during modified Taylor impact tests was investigated. Samples were impacted against a steel or sapphire anvil at a nominal velocity of 150 m/s. A framing camera was used to capture head-on and sideprofile impact images for the sapphire window and steel plate rigid anvils, respectively. Correlations were drawn between both experimental setups to determine the initiation locations and reaction times. Reactions were found to initiate at an intermediate radius on the impact face of the pellet at a time near full compaction. From simulations, the highest strains and temperatures were found at radii similar to those observed in experiments at the time of ignition. Off-normal impacts produced higher localized straining and temperatures on one-half of the pellet. The copper projectile, used for delivery, was revealed to aid in a shear assisted reaction by helping to drive the pellet material outward as the projectile deformed radially.

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Section: Modeling Results and Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Impact Initiation of Reactive Aluminized Fluorinated Acrylic Nanocomposites

White

Crouse

Spowart

et al. 2016

J. dynamic behavior mater.

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“…Experiments shown initiation only when grits were used meaning that higher velocity and pressure are needed to ignite the explosive when sliding occurs on grit-free surfaces. This analysis was experimentally confirmed for PBX 9501 [10][11][12][13]. If an impact on a target made of glass does not show reactive event, the addition of free-grits on the surface of the target can result in light and explosion.…”

Section: Introductionmentioning

confidence: 78%

“…As a consequence of these finite element simulations, neither friction nor plastic shear can ignite our HMX-based explosive compositions. The influence of the abrasive paper on our experimental results and its interaction (friction) on the steel plate must to be reconsidered in the future as highlighted in previous researches [9][10][11][12][13].…”

Section: Finite Element Evaluation Of the Heatingmentioning

confidence: 99%

“…If an impact on a target made of glass does not show reactive event, the addition of free-grits on the surface of the target can result in light and explosion. Authors of [9][10][11][12][13] proposed the following interpretation: the sand grits having higher melting temperature than the PBX, their friction to the glass increases their temperature, then the grits acting as fixed "hot-spots" for the explosive part.…”

Section: Introductionmentioning

confidence: 99%

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Oblique Impacts and Friction of HMX and/or TATB‐based PBXs

Picart

Junqua-Moullet

2017

Propellants Explo Pyrotec

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Transportation, handling, vibrations can lead to dynamic loadings requiring the characterization of the safety of plastic‐bonded explosives (PBX). One of the addressed situations is the fall of explosive on a surface. Knowing that initiation can occur at a lower height during a vertical fall of a projectile on an inclined target than on a horizontal one, devices were developed to determine the critical thresholds. In this paper, data obtained on four HMX and/or TATB‐based PBXs using pendulum drop configurations are detailed. Two analytical models are compared to estimate the heat released by friction at the interface. The model proposed in this paper yields the better agreement with data, and with finite element numerical simulations of the oblique impact on a given PBX. Lastly, the mechanical dissipation at the interface is estimated using this model and the simulations. This paper confirms that PBX/target friction cannot be the heating mechanism leading to initiation during oblique impacts.

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Variation of Methods in Small‐Scale Safety and Thermal Testing of Improvised Explosives

Sandstrom

Brown

Preston

et al. 2014

Propellants Explo Pyrotec

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One of the first steps in establishing safe handling procedures for explosives is small‐scale safety and thermal (SSST) testing. To better understand the response of homemade or improvised explosives (HMEs) to SSST testing, 16 HME materials were compared to three standard military explosives in a proficiency‐type round robin study among five laboratories, two U.S. Department of Defense and three U.S. Department of Energy, sponsored by the Department of Homeland Security, Science & Technology Directorate, Explosives Division. The testing included impact, friction, electrostatic discharge (ESD) and thermal. The testing matrix was designed to address problems encountered with improvised materials: powder mixtures, liquid suspensions, partially wetted solids, immiscible liquids, and reactive materials. All testing materials and/or precursors came from the same batch distributed to each of the participants and were handled, pretreated, and mixed by standardized procedures. For this proficiency test, the participants had similar equipment, usually differing by vintage. This allowed for a direct comparison of the results from each participant to the average of the results from all the participants. Some general trends observed for each series of tests were: (1) Drop hammer – LLNL usually found the materials less sensitive than the average with materials that have high sensitivity to impact and LANL usually found the materials less sensitive than the average with materials that have high sensitivity to impact; (2) friction – LLNL found the materials less sensitive than the average; (3) and ESD – IHD usually found the materials less sensitive than the average. In this report, the proficiency test data from all the participants is compared and contrasted for impact, selected friction, and ESD testing. Other friction and thermal data will be addressed elsewhere as well as the statistical analysis of several repeated measurements on the proficiency test standards.

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Impact-induced friction ignition of an explosive: Infrared observations and modeling

Cited by 28 publications

References 10 publications

Impact Initiation of Reactive Aluminized Fluorinated Acrylic Nanocomposites

Impact Initiation of Reactive Aluminized Fluorinated Acrylic Nanocomposites

Oblique Impacts and Friction of HMX and/or TATB‐based PBXs

Variation of Methods in Small‐Scale Safety and Thermal Testing of Improvised Explosives

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