Feasibility Study of a Fail-Safe Through Bulkhead Initiator

摘要

The design status of a through bulkhead initiator (TBI) is presented. The TBI design consists of a high explosive donor which when detonated transmits a shock wave through a metal bulkhead to initiate an acceptor explosive without destroying the integrity of the bulkhead. There are at least two potential applications for such a device. The combined requirements of the two applications are severe in several aspects, namely: fail-safe, small size, and controlled function time. The PETN donor output was characterized by velocity interferometer techniques. Two methods of controlling the output were demonstrated: (1) controlling the density of the donor and (2) controlling the length of the donor column (in relationship to the bulkhead thickness). The Type 304L stainless steel bulkhead was designed using a combination of experimental and analytical techniques to assure both function and integrity. The Type 304L provides a single shock rather than a multiple wave structure and exhibits high ductility. The PETN selected for the acceptor was chosen on the basis of shock sensitivity testing in which the morphology of the explosive and the wave shape of the stimulus entering the explosive played key roles. When tested with a short pulse (40 ns, rectangular), the small particle size PETN initiated at a lower pressure than did the large particle size PETN; when tested with a long pulse (280 ns, triangular), the large particle size PETN initiated at a lower pressure than did the small particle size PETN. (ERA citation 05:021119)