Improvements to Build Techniques for Cylinder Tests & Gas-Gun Trials

The Cylinder Expansion (CylEx) test is a key tool for obtaining detonation product equation of state information. Build tolerances generally cause small air gaps between the explosive charge and the surrounding copper liner. These gaps cause the jetting phenomena observed in front-curvature measurements of the charge end. Jetting appears as bright “horn-like” features that run ahead of the detonation wave. A previous solution replaced air in the gap with a gel lubricant. Here we present a new method for consistent application of gel, and an initial study into the different potential gap-filling options, including water and silicone-based lubricants. This assessment was performed using an inert-material assembly. The effectiveness at preventing air gaps was assessed by visual methods and considered against both material compatibility and ease-of-assembly. Dynamic testing of the selected fillers is planned. Complimentary work is also presented, which investigates different techniques for applying a thin and even glue layer in gas-gun target builds. These were tested using a representative setup, and characterised using a white-light interferometer.

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