High fidelity studies of exploding foil initiator bridges, Part 1: Experimental method

Bowden, Mike; Neal, William

doi:10.1063/1.4971576

Cited by 12 publications

(7 citation statements)

References 2 publications

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“…Therefore, minus sign (À ) was taken in equation (6). Since p J is much larger than p 0 , so the latter is negligible, and D J equals to D 0 , then equation ( 6) was deduced as (7) Introducing a parameter ξ, the equations of weak detonation were simplified as (8) If assuming the electro-explosion of exploding foil is realized in a moment, namely D!∞, then ξ equals to 1, and equation ( 8) was reduced to (9) Compared with typical explosives, polytropic exponent of metal vapor is no longer equals to 3, Riemann constant must be considered: (10) Due to α ¼ 6 u + c, shock pressure and sound speed were written as (11) (12) According to Newton's Second Law, equation of motion can be described as (13) where m f , s f are the mass and effective area of flyer, respectively. Inserting equation ( 11) and ( 12) into equation ( 13), it will be transformed as (14) Joining with initial conditions u(0) = 0 and x(0) = l, the relationship between flyer velocity and time can be obtained by integral calculus as (15) Meanwhile, the flight trajectory x(t) can be obtained as (16) where h b is the thickness of the bridge foil.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…In an EFI, it is clear that plastic flyer plays an important role, which transfers the energy from metal vapors to secondary explosives. Traditionally, polyimide film was used as a flyer, because of its excellent mechanical properties, thermal stability, and dielectric strength [7][8][9]. In recent years, parylene C is becoming a potential choice.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Analysis on Acceleration Process and Shock Initiation of Parylene C−Cu Flyer in Exploding Foil Initiator

Liu

2022

Propellants Explo Pyrotec

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Parylene C flyer coated with copper film was often used to shock and initiate insensitive explosives in exploding foil initiator (EFI). However, there were few studies on the acceleration process of parylene C−Cu flyer and the shock initiation induced by parylene C−Cu flyer. In this paper, exploding bridge foil was treated as a kind of special explosive to launch parylene C−Cu flyer, and an instantaneous explosion model was established to describe the acceleration process mathematically. Then, two‐dimensional numerical simulations were carried out using ANSYS/AUTODYN software to analyse the flight history and morphology of parylene C−Cu flyer, as well as the effect of copper film on flyer velocity. Finally, shock initiation of parylene C−Cu flyer impacting ultrafine hexanitrostilbene (HNS‐IV) was also simulated, and the initiation threshold was determined by adjusting the flyer velocity at the collision moment. Compared with previous work, calculated results exhibit good agreement with the experimental data, that is addition of Cu film can indeed improve the shock pressure but leads to lower flyer velocity. For parylene C−Cu flyer with the thickness of 25 μm–3.6 μm, its flyer velocity drops to half of parylene C flyer under same operation conditions, and the initiation threshold that can initiate the HNS‐IV pellet is 2300 m/s. All the results demonstrate that the numerical approach will be useful for the optimization of parylene C−Cu flyer, even any kind of multi‐layer flyer.

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Section: Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Analysis on Acceleration Process and Shock Initiation of Parylene C−Cu Flyer in Exploding Foil Initiator

Liu

2022

Propellants Explo Pyrotec

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“…Both were pressed into the column and then fixed on the barrel of the McEFI with the tape. The pellet's density was 1.60 g/cm 3 , with a size of 4 mm (Φ) × 3 mm (H). Figure 8 displays the firing device the CDU used to initiate the HNS.…”

Section: Initiation Testmentioning

confidence: 99%

“…With an increasingly harsh operating environment, higher requirements are placed on the safety and reliability of pyrotechnic devices. The exploding foil initiator (EFI) has more advantages over traditional ignition and initiation devices on reliability and safety, since there are no primary explosives in the initiation sequence [1][2][3][4]. The EFI, as a part of the pulse power unit or capacitor discharge unit (CDU), plays an important role in electronic safety and arming device (ESAD) [5].…”

Section: Introductionmentioning

confidence: 99%

Firing Performance of Microchip Exploding Foil Initiator Triggered by Metal-Oxide-Semiconductor Controlled Thyristor

Wang

Zhu

et al. 2020

Micromachines

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In this paper, microchip exploding foil initiators were fabricated by micro-electro-mechanical system scale fabrication methods, such as magnetron sputtering, photolithography, and chemical vapor deposition. A small-scale capacitor discharge unit based on the metal-oxide-semiconductor controlled thyristor was designed and produced to study the performance of the microchip exploding foil initiator. The discharge performance of the capacitor discharge unit without load and the effect of protection devices on the metal-oxide-semiconductor controlled thyristor were studied by the short-circuit discharge test. Then, the electric explosion characteristic of the microchip exploding foil initiator was also conducted to study the circuit current, peak power, deposited energy, and other parameters. Hexanitrostilbene refined by ball-milling and microfluidic technology was adopted to verify the initiation capability of the microchip exploding foil initiator triggered by the metal-oxide-semiconductor controlled thyristor. The results showed that the average inductance and resistance of the capacitor discharge circuit were 22.07 nH and 72.55 mΩ, respectively. The circuit peak current reached 1.96 kA with a rise time of 143.96 ns at 1200 V/0.22 μF. Hexanitrostilbene fabricated by ball-milling and microfluidic technology was successfully initiated at 1200 V/0.22 μF and 1100 V/0.22 μF, respectively.

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“…An exploding foil initiator (EFIS) is a short-pulse electric signal ignition device, and its core component is an explosive metal foil. Under the action of a high pulse current, the explosive metal foil completes the transformation of solid, liquid, gas and plasma in a very short time, forming a high-temperature and high-pressure plasma, thus promoting a flyer to impact and detonate the explosive [1][2][3][4][5]. Due to the high safety of impact plate detonators, since their introduction in a report from Lawrence Livermore National Laboratory in the United States, exploding metal foil initiators have rapidly become a popular research topic [6].…”

Section: Introductionmentioning

confidence: 99%

Study on Electrical Explosion Properties of Cu/Ni Multilayer Exploding Foil Prepared by Magnetron Sputtering and Electroplating

et al. 2020

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The purpose of this study was to investigate the effects of the microstructure and properties of Cu/Ni multilayer films prepared by magnetron sputtering and electroplating on the electrical explosion performance of the films. In this study, Cu/Ni multilayer films of the same thickness were prepared by electroplating (EP) and magnetron sputtering (MS), and their morphology and crystal structure were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD was used to observe the crystal structure and size of the samples. In addition, the Cu/Ni multilayer film was etched into the shape of a bridge, and the electric explosion phenomenon in the same discharge circuit of the multilayer foil obtained by the two preparation processes was tested by an electric explosion performance test system. The resistance–time curve and the energy–resistance curve during the electric explosion process were analyzed and calculated. The results showed that compared with the multilayer film prepared by the MS method, the crystal size of the multilayer film prepared by the EP method is smaller and the interface of Cu/Ni is clearer. In the electric explosion experiment, the MS samples had earlier burst times, larger peak resistances, smaller peak energies and higher ionization voltages. Through observation of the morphology of the samples after the electric explosion and combination with gas ionization theory, the internal influencing factors of the peak voltage and the relative resistance of the two samples were analyzed. The influence of the multilayer film mixing layer thickness on the sample energy conversion efficiency was analyzed by modeling the microstructure of the multilayer film exploding foil and electric heating. The results show that the thicker the mixing layer is, the more energy is distributed on the Ni, the faster the resistance increases, and the higher the energy conversion efficiency.

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High fidelity studies of exploding foil initiator bridges, Part 1: Experimental method

Cited by 12 publications

References 2 publications

Numerical Analysis on Acceleration Process and Shock Initiation of Parylene C−Cu Flyer in Exploding Foil Initiator

Numerical Analysis on Acceleration Process and Shock Initiation of Parylene C−Cu Flyer in Exploding Foil Initiator

Firing Performance of Microchip Exploding Foil Initiator Triggered by Metal-Oxide-Semiconductor Controlled Thyristor

Study on Electrical Explosion Properties of Cu/Ni Multilayer Exploding Foil Prepared by Magnetron Sputtering and Electroplating

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