ANFO and TNT anti-vehicle mine blast: Experimental and numerical observations

Anti-vehicle (AV) mines and Improvised Explosive Devices (IEDs) pose a major threat in recent and current missions. In the latest operational theatres of Iraq and Afghanistan they have been responsible for a significant proportion of all casualties. Understanding both the characteristics and strength of the blast loading from these devices is essential for both the design and evaluation of mine-blast resistant vehicles. As part of this process TNO evaluated a range of TNT and ANFO buried charges. Selected results from these tests are reported here. Whilst TNT is a common military explosive, ANFO is readily available to insurgents and forms the actual threat. A buried charge will focus the blast towards the vehicle due to the explosive interaction with the soil. The loading characteristic from the detonated charge is a combination of the power (brisance) and strength (heave effect) of the explosive. Whilst TNT is more powerful than ANFO with a higher brisance, ANFO has a higher observed strength than TNT with a higher heaving effect. The ANFO and TNT experimental results are being used to develop and validate the TNO Mine Blast Model [1] implemented into the commercial code LSDYNA. This provides a numerically efficient and robust method for simulating a buried mine blast.