The effect of surface heterogeneities in exploding metal foils

Neal, William; Sanchez, Nathaniel; Jensen, Brian J.; Gibson, John R.; Romero, J.W.; Martinez, M. E.; Owens, Charles; Jaramillo, Dennis; Iverson, A. J.; Carlson, Carl A.; Teel, Matthew G.; Derry, Alex; Rigg, P. A.

doi:10.1063/1.5045040

Cited by 7 publications

(2 citation statements)

References 7 publications

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“…The increased resistivity, and therefore heating, of locations across the wire lead to a variety of thermodynamic states throughout the entirety of the wire. This phenomenon has also been witnessed in real detonator components; both EBWs [25] and EFI detonators [26,27]. Figure 8 and Figure 9 show the results of these EFI and EBW studies respectively and it can be seen in both that the density varies dramatically during explosion as a result of ETI.…”

Section: Electrothermal Instabilitiessupporting

confidence: 62%

PETN Exploding Bridgewire (EBW) Detonators: A Review

Neal

2020

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Exploding bridgewire (EBW) detonators have been used in weapon systems since the 1940s but there is huge debate surrounding how energy is transferred throughout the EBW firing system and the mechanism by which the exploding wire leads explosive detonation. This report summarizes the underpinning technologies and physical processes that are currently understood and reviews the various efforts to quantify the mechanism by which the PETN is initiated. The behavior of the firing system is very well understood and predictable. The energy delivered to the wire has been empirically modelled but further investigation is required to understand the role of material heterogeneities and their effect on initiation. The energy delivered by the exploding wire has been quantified in many studies but it is not possible to correlate these to a particular design or firing regime and thus definitive conclusions are impossible. The energy absorbed by the PETN is also not well understood. Therefore, the initiation mechanism within the PETN EBWs has not been determined for EBW detonators. There is strong evidence that a shock-todetonation (SDT) mechanism is not the sole cause of initiation. There is insufficient understanding of how electrical sparks transmit energy to PETN to make any judgement regarding the role gas ionization plays. Deflagration-to-detonation (DDT) seems like the most likely candidate for initiation but there is still a great lack of evidence for the presence of this mechanism.

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Section: Electrothermal Instabilitiessupporting

confidence: 62%

PETN Exploding Bridgewire (EBW) Detonators: A Review

Neal

2020

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“…Magnetron sputtering and photolithography are commonly employed processes for fabricating blast foil transducer elements [8][9][10]. During the fabrication of metal bridge foils, various defects of different shapes and depths such as blind holes, through-holes, and scratches can arise on the surface of the exploded foil transducer element due to factors such as holes, pits, burrs, foreign particulate matter, and target droplets on the substrate surface [11][12][13][14][15]. Eliminating film defects entirely is challenging [16], and even when films are deposited using HiPIMS, an advanced physical deposition method, a significant number of defects can still occur [17].…”

Section: Introductionmentioning

confidence: 99%

Impact of Through-Hole Defects on the Electro-Explosive Properties of Exploding Foil Transducers

Wang¹,

Wang

et al. 2023

Micromachines

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This study examines the impact of surface defects on the electro-explosive properties of metal explosive foil transducers. Specifically, it focuses on the effects of defects in the bridge foil and their influence on the electrical explosion time and transduction efficiency. To analyze these effects, a current-voltage simulation model is developed to simulate the behavior of a defective bridge foil. The simulation results are validated through experimental current-voltage measurements at both ends of the bridge area. The findings reveal that the presence of through-hole defects on the surface of the bridge foil leads to an advancement in the electrical explosion time and a reduction in the transduction efficiency of the bridge foil. A performance comparison is made between the defective bridge foil and a defect-free copper foil. As observed, a through-hole defect with a radius of 20 μm results in a 1 ns advance in the blast time and a 1.52% decrease in energy conversion efficiency. Similarly, a through-hole defect with a radius of 50 μm causes a 51 ns advancement in the blast time and a 13.96% reduction in the energy conversion efficiency. These findings underscore the detrimental effects of surface defects on the electro-explosive properties, emphasizing the importance of minimizing defects to enhance their performance.

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