Abstract
Miniaturization of exploding foil initiator (EFI) system with micron-sized bridge foil (～200×200 µm2) may provide substantial improvement on detonator reliability and safety as well as manufacturing cost by lowering all-fire operational voltage and relieving many constraints on system design and fireset components. This numerical modeling study presents thermomechanical modeling on plastic flyer acceleration after bridge foil burst by pulsed energy input and high-speed flyer impact detonation initiation of HNS-IV explosive charges in such microscale EFI systems and low-energy fireset circuit. The compensation of deviation from linear bridge vapor expansion is introduced and detonation initiation criteria is recalibrated based on firing test results with thin flyer thickness in present modeling. The computational results on flyer velocity is well validated against the firing test measurements of EFI system with copper bridge foil and polyimide flyer. The influences of bridge and flyer thicknesses on detonation threshold are thoroughly investigated and the combined range of bridge and flyer thicknesses could be suggested for optimal EFI design of micron-sized bridge foil in terms of minimization of threshold charging voltage.
