Dr Rebecca Stephens
Senior Secondary Explosive Scientist
A Senior Secondary Explosive Scientist working for BAE Systems, Rebecca Stephens has over 10 years of experience in the energetics industry. Rebecca’s main area of interest is Polymer Bonded Explosives PBX where she has been involved with the formulation and processing of materials for applications including gun/tube launch and complex warheads.
A synthetic chemist by training Rebecca has recently reignited her passion for synthesis and has a keen interest in developing novel molecules that can be used to improve the performance of PBX both in process and in application.
The first generation of Polymer Bonded Explosives (PBX) were first developed in the 1950s, when technology that was first developed in rocket motors was incorporated into High Explosive applications. PBX has since found application in missile, torpedo and gun launch systems. They have enjoyed widespread use not only due to their end effect performance but also because of their ability to fulfil the requirement for Insensitive Munitions (IM). Since their inception PBX have seen limited evolution.
This is largely due to the processing methods available for munition filling. Traditionally PBX has been prepared using high shear planetary mixers then cast under vacuum. This process, particularly the casting, requires a mobile slurry that is easily poured. The criticality of the viscosity of the PBX slurry has limited the changes that could be made to improve its performance.
Any modification that results in a significant increase to slurry viscosity cannot be implemented as it will render the PBX unprocessable. As munitions manufacturers design systems to respond to new threats, the demands on PBX containing systems are becoming greater. In the area of missile technology, for example, there is a requirement for munitions to be able to survive in flight at high mach speeds.
There are concerns that the current PBX offerings will lack the mechanical strength to cope in such environments. Fortuitously, a new technology has been identified which could free PBX formulation from the constraints it has suffered under traditional processing regimes. Resonant Acoustic Mixing (RAM) is a technology with the potential to introduce an enduring change to the approach to mixing and filling of PBX. The ability to mix in the munitions casing (MIC), without the need form a mixing bowl or casting process has the potential to realise improvements to PBX performance that have previously been unattainable.