Performance characterization of a miniaturized exploding foil initiator via modified VISAR interferometer and shock wave analysis

Abstract

A pyrotechnic device that consists of a donor/acceptor pair separated by a gap or a bulkhead relies on the shock attenuation characteristics of the gap material and the shock sensitivity of the donor and acceptor explosives. In this study, a miniaturized exploding foil initiator, based on high pulsed electrical power generator, was designed to launch a micro Kapton® flyer for impact initiation of a high explosive in order to understand its performance characteristics. Here, the explosive substance was replaced with a witness plate because the flyer poses various flight motions of rotation, bend, and fragmentation due to its extreme thinness. By using a Velocity Interferometer System for Any Reflector and ANSYS Explicit Dynamics, the averaged velocity of a flyer is measured, which then allows for the calculation of the shock pressure and the duration imparted to the explosive for an initiation. Subsequently, the relationship between the flyer velocity, the amplitude, and the width of impact loading can be used to assess the performance of the designed exploding foil initiator of a micro pyro-mechanical device.

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

“…The initiation energy of the McEFI not only depends on the particle size of the HNS, but also the flyer speed. Flyer kinetic energy or speed is the most important indicator to assess whether the HNS can be initiated [28]. According to the P-τ theory, the dynamic pulse high pressure generated by the flyer impacting the HNS leads to the initiation of the HNS [29,30].…”

Ignition sensitivity study of an energetic train configuration using experiments and simulation

“…The compressible Navier-Stokes equations in a twodimensional coordinate system reflect the conservation of mass, momentum and energy as shown in Eqs. (1), (2), and…”

“…Ignition sensitivity study of an energetic train configuration using experiments and simulation Bohoon Kim, 1 Hyeonju Yu, 2 and Jack J. Yoh 1,a) 1 Seoul National University, Seoul 151-742, South Korea A full scale hydrodynamic simulation intended for the accurate description of shock-induced detonation transition was conducted as a part of an ignition sensitivity analysis of an energetic component system. The system is composed of an exploding foil initiator (EFI), a donor explosive unit, a stainless steel gap, and an acceptor explosive.…”

Investigation of Electrically Heated Exploding Foils in Reactive Al/Ni Multilayer

“…When high current pulse is passing through metallic foil or wire in short time, the state of foil or wire changes from solid to vapor rapidly, resulting plasma with high temperature and pressure by ionized vapor. The plasma created by metallic foil or wire has many applications in electrical guns (EGs) [1][2][3][4], exploding foil initiator (EFIs) [5][6][7][8][9], exploding wire initiator. The high pressure generated by plasma can accelerate plastic flyers to km/s, which can initiate explosion or investigate impacting performance of materials.…”