Susceptibility of Electro-Explosive Devices to high pulsed electric fields

Abstract

Commercially available Electro-Explosive Devices (EEDs), such as blasting caps, use electrical current to initiate a primary charge. Various detonators including bridge wire, match-type, exploding bridge wire, and slapper. The basic operating principle of the match-type device is to heat the ignition element to the ignition temperature of the primary explosive. The normal operation current profiles, both constant current and pulsed excitation, are well known, as is the ignition temperature. However, as safety and reliability are of great concern, both in the operation and storage of EEDs, the susceptibility of these devices to transient or spurious fields is of interest. The susceptibility of match-type EEDs to high pulsed electric fields is examined. A Finite Element Method (FEM) simulation is performed using COMSOL to determine the induced current in the bridgewire due to applied electric fields and the resulting Joule heating of the wire. Several situations are investigated including the EED in conductive and non-conductive media and leads open or terminated representing operational and storage conditions.