An electro-explosively actuated mini-flyer launcher

Xu, Cong; Zhu, Peng; Wang, Ke; Xin, Qin; Zhang, Qiu; Yang, Zhi; Shen, Ruiqi

doi:10.1016/j.sna.2019.03.027

Cited by 14 publications

(9 citation statements)

References 16 publications

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“…Compared with the measured flyer velocity (4400 m/s) in Ref. [16], calculated flyer velocity agrees well when assuming the bridge foil is totally ionized (namely the energy deposited into bridge foil is the sum of melting, vaporization and ionization), which indicates that the assumption of the instantaneous explosion is appropriate. Besides, it can be seen that actual flyer velocity has reach to T ~1000 m/s at t = 0 in calculated flyer velocity, which was also observed by the experimental method [13].…”

Section: Flyer Acceleration Processsupporting

confidence: 66%

“…Besides, calculated parylene CÀ Cu flyer velocity is slightly higher than the experimental data (2367 m/s) in Ref. [16], possibly because of the impedance of copper layer intensifies the energy dissipation on ablation of parylene C [27].…”

Section: Flyer Acceleration Processmentioning

confidence: 56%

“…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%

“…On the other hand, it's well-known that metal film deposited on plastic flyer can enhance shock pressure since the former has higher wave impedance [14][15]. In 2019, C. Xu studied the velocity characteristics of parylene CÀ Cu flyer with the thickness of 25 μm-3.6 μm under a series of operation voltages and found that the firing threshold that can initiate HNS-IV is 1100 V when high voltage capacitor is 0.22 μF [16]. Before that, C. Xu also studied 25 μm-thick parylene C flyer, and the critical flyer velocty that initiate HNS-IV was obtained at 0.22 μF/1400 V [12].…”

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: Flyer Acceleration Processsupporting

confidence: 66%

Section: Flyer Acceleration Processmentioning

confidence: 56%

Section: Mathematical Modelmentioning

confidence: 99%

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

Self Cite

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“…In 2018, Wang Runyu et al [19] used an improved manufacturing process to replace the wet etching process to prepare a miniature metal bridge foil explosive planar switch, and studied the influence of the thickness of the adhesive layer and the insulation method on the insulation effect in the switch insulation treatment. In 2020, Xu Cong et al designed three trigger modes: the Schottky diode [20], pn junction diode [21], and micro bridge foil [22,23] based on the planar dielectric explosion high voltage switch of the Schottky diode, such as the Baginski TA flat dielectric high voltage switch. The electrical characteristics of the three switches are preliminarily studied, and the results show that, among the three trigger mode switches, the micro-foil planar dielectric switch can obtain the highest peak current and the shortest rise time at a lower operating voltage.…”

Section: Introductionmentioning

confidence: 99%

Research on Characteristics of Copper Foil Three-Electrode Planar Spark Gap High Voltage Switch Integrated with EFI

et al. 2022

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In view of the low-energy explosion foil detonation system’s requirements for the integration technology of high-voltage switches and technical overload resistance technology, a magnetron sputtering coater is used to sputter copper film on the surface of the substrate. The thickness is 4.0 μm, the radius of the main electrode is 4 mm, the trigger electrode is 0.6 mm and 0.8 mm, and the main gaps are 0.8 mm, 1.0 mm, 1.2 mm mm, 1.8 mm, 2.0 mm, 2.2 mm, and 2.6 mm. Copper foil three-electrode planar spark gap high voltage switches are designed and manufactured; and the static self-breakdown characteristics, dynamic operating characteristics, and discharge life characteristics of the three-electrode planar spark gap high voltage switch based on copper foil are studied in this paper. The test results show that with the increase of the main electrode gap from 0.8 mm to 2.6 mm, the self-breakdown voltage of the planar spark gap switch increases, and the working voltage also increases. When the main electrode gap is a maximum of 2.6 mm, the self-breakdown voltage of the switch can reach 3480 V, which indicates that the maximum operating voltage of the switch is 3480 V. When the charging voltage is 2.0 kV, with the increase of the main electrode gap from 0.8 mm to 2.6 mm, the minimum trigger voltage value of the planar spark gap switch increases from 677 V to 1783 V (a = 0.6 mm), and from 685 V to 1766 V (a = 0.8 mm), the switch on time is 16 ns, 22 ns, 28 ns, 48 ns, 64 ns, 77 ns, 93 ns (a = 0.6 mm), and 26 ns, 34 ns, 51 ns, 67 ns, 81 ns, 102 ns (a = 0.6 mm). With the increase of the gap between the two main electrodes of the switch, the maximum static working voltage of the three-electrode plane spark gap high-voltage switch increases, the minimum trigger voltage value also increases, and the on-time of the switch gradually becomes longer. The peak current of the discharge circuit decreases and the dynamic impedance and inductive reactance of the switch also increase; as the width of the trigger electrode increases, the minimum trigger voltage decreases, the dynamic impedance and inductance decrease, and the switch operating voltage with the same parameters is higher. The easier the switch is to turn on, the lower the minimum trigger voltage. The electrode thickness of the three-electrode plane spark gap switch has a certain influence on the field strength and the service life of the switch. The results of this study provide useful references for promoting the research and development of LEEFIs.

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Optimizing cure temperature of polyimide flyer for exploding foil initiator applications

Sun

Zhan

et al. 2022

J of Applied Polymer Sci

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Polyimide (PI) is an ideal flyer material commonly used for exploding foil initiator (EFI) systems. The material properties of PI influence the flight ability of the flyer. Curing temperature during the preparation process of PI is one of the key factors influencing the material properties. In this study, we investigated the effect of the PI film curing temperature on the material properties and the flight ability by characterizing IR transmittance, XPS, and nano-hardness. The results show that the flight ability of the flyer is highly dependent on the curing temperature. Curing at 250 C is beneficial for the flyer to have an optimal flight velocity, which was attributed to the good chemical and mechanical behavior of the material. Increase in curing temperature would weaken the material properties to some extent.High-temperature cure (e.g., 400 C), would break the molecular chain and carbonize the material, causing significant drop in flight velocity of the flyer. The study is expected to contribute to the development of high-performance flyer for EFI applications.

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An electro-explosively actuated mini-flyer launcher

Cited by 14 publications

References 16 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

Research on Characteristics of Copper Foil Three-Electrode Planar Spark Gap High Voltage Switch Integrated with EFI

Optimizing cure temperature of polyimide flyer for exploding foil initiator applications

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