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The simulation presents the 120mm STAFF shell's explosively formed penetrator impacting Kontakt-1 explosive reactive armour (ERA) on the roof of the T-72. The Smart Target-Activated Fire and Forget projectile was an American prototype munition developed for 120mm tank cannons in the late-20th century. The projectile could detect and track targets, then flying overhead and firing an EFP downwards onto the roof of the vehicle. The project was cancelled at the end of the 1990's, but the projectile has lived on in video games such as Battlefield. TO NOTE: Due to lack of information and computational constraints, certain aspects of the simulation had to be omitted or approximated, however these aspects should not have a large effect on the overall result: 1. The XM943 STAFF Projectile Internal diagrams could not be found, so everything inside the shell was approximated, including the EFP. However, seen as the projectile is 120mm in diameter, the EFP cannot be larger than this, so with the thickness of the shell and EFP walls, the diameter of the EFP liner is likely to be around 100mm (it is exactly 100mm in the simulation). The liner material and thickness also had to be assumed, but due to how small the EFP is, it is likely that everything was done to maximise performance, hence the choice of a 4mm Tantalum liner -one of the most ideal materials for an EFP, with a thickness/diameter ratio suiting its high density. The explosive used in the model is Octol, just because it is also found in the American CBU-97 cluster bomb EFPs. 2. Computational Constraints (Velocity and Casing omission) For the explosive material, a domain needs to be defined, however the mesh within it needs to be relatively fine so it doesnt seep through thin structures. So the explosive domain was only put in a small area around the EFP, and not the whole projectile to minimise the number of elements. However, as the walls of the shell around the EFP are very thin, this caused issues with seep-through and meant the simulation would take weeks to solve. The same issue would occur when the other parts of the projectile would move into the explosive domain (due to the projectile's velocity), hence why both the velocity and casing were omitted. This wouldnt make too much of a difference apart from the EFP coming in at a slight obliquity. 3. ERA The geometry of the Kontakt-1 was taken from the Soviet armour blog, and its acceleration defined by a variable pressure load based on the Gurney and Flis equations. It is uncertain if the ERA would even detonate when impacted by the EFP, as it is insensitive and mainly meant for shaped charge its much more interesting if it does detonate. Amazing Thumbnail artwork from: air-fox
