Modeling Microfabricated Multipoint Fuze Initiators Part 1: Pre-Melting Behavior

Report No. ARL-TR-4371
Authors: Christopher J. Morris, Eugene Zakar, Brian Mary, Edward Shaffer, Paul Amirtharaj, and Madan Dubey
Date/Pages: January 2008; 34 pages
Abstract: Future combat systems require warheads with multi-point initiators to produce precise simultaneous detonations. Semiconductor fabrication methods, combined with MEMS-enabling process technologies at ARL, enable geometrically accurate conductorsbridge wire for such multi-point initiators. To understand how our device design, material deposition, and post processing influence bridge wire performance and ultimately simultaneity, we have simulated the behavior of an exploding metal bridge. In this report we present results focusing on the thermal-electric problem of heating up to the bridge wire melting point. The results in terms of time for the center of the exploding foil to reach the material melting temperature was within 2% of a similar, published modeling study, and approximately within 20% of the experimentally-observed time-to-burst for specific geometries fabricated at ARL. We also performed a sensitivity study and found the melting time to be most sensitive to bridge wire thickness, and all material properties except thermal conductivity. Simple, analytical arguments explain these results. Finally, we detail a path forward to eventually result in a predictive model allowing direct comparison between model outputs and experimental data. Such a model will greatly enhance our ability to design better bridge wire devices.
Distribution: Approved for public release
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Last Update / Reviewed: January 1, 2008