XPT (eXplosion Protection Technology) can most simply be described a 'stone sponge'. Its inherent porosity allows the blast shockwave to enter its structure. There, thousands of small air chambers slow the blast wave down, trapping it and then making it expend it itself by breaking up the structure of the XPT.
There are a number of different stages in the breakdown of XPT and it takes a very severe blast loading to get through all of them. Each stage, through its specific mechanism, takes more energy out the blast, protecting the structure or object behind it and also reducing the energy reflected off it.
XPT is a practical engineering material. Panels or mouldings can be cast into many shapes, requiring only simple and inexpensive mould tools. It has excellent fire resistance, reduces ambient noise and helps in the retardation of the fragments often generated in an explosion.
In Spring 2010 a series of tests was undertaken to demonstrate the performance of the XPT system.
A question often posed by vehicle armourers is why they shouldn't just use thicker steel rather than apply the XPT material to their protective system. These test set out to answer that question.
The existing test data to support the case for XPT was gathered during customer projects and so was proprietary. What was needed was a clear demonstration that could be openly discussed and made freely available.
Using the facilities and test team at Ordnance Test Solutions, a series of explosive tests was performed to compare plain 8mm thick armour steel structures against 4mm thick armour steel with a 20mm thick XPT facing. These material thicknesses resulted in weight-matched structures making it easier to compare material performance.
This simple, generic structure also served to remove a lot of the complexities that would arise using actual wheel arch sections.
For the onset of weld cracking the XPT faced material had a limit of 1.66 higher than the plain steel and for failure of the welds this performance difference had increased to a factor of 1.75. These results exceeded expectations and clearly demonstrate that the application of XPT is advantageous compared to just using thicker steel for such confined conditions.
For a copy of the full report please contact SJH Projects using the enquiry form.