The Dynamic Behaviour of the Floor of a Surrogate Vehicle Under Explosive Blast Loading

Nicolas Newell,Thanyani Pandelani,William G Proud,Spyros D Masouros,David Reinecke,William Neal

doi:10.5539/jmsr.v5n2p65

Abstract

<p class="1Body">Improvised Explosive Devices have been the signature weapon in the recent conflicts in Iraq and Afghanistan. High-rate axial forces exerted by the vehicle floor to the lower limbs of occupants have been the cause of severe injuries. In order to gain a greater understanding of the mechanisms of these injuries so that countermeasures can be developed, one is required to know how the vehicle floor behaves; therefore, the purpose of this study was to characterise the behaviour of a vehicle floor surrogate to a range of explosive loads. Explosive loads between 1 and 6 kg TNT were detonated beneath a vehicle floor surrogate resulting in peak floor velocities between 5.8 and 80.5 m/s reached in a time between 0.10 and 3.13 ms. The data can now be used to (a) test numerical models of blast and its interaction with structures for validity, and (b) ensure that the velocity profiles replicated in a laboratory environment to understand human tolerance to injury are relevant to the blast process. These will ensure that preventive measures are developed based on realistic physical and numerical models of injury.</p>

Highlights

The use of the improvised explosive device (IED) from insurgents against Coalition Troops and civilians has epitomised the recent conflicts in Iraq and Afghanistan
Instrumentation failures meant that Photonic Doppler Velocimetry (PDV) data was not obtained at any location for tests 1 and 6 (1 kg flush buried and 6 kg flush buried), and at the furthest location (650 mm from the centre) for test 4
There are a number of factors which may contribute to the longer time to peak velocity predicted by the numerical model; while their charge was similar in terms of size to the largest used in this study, it was buried by 88.1 mm compared to flush buried, it was not located directly beneath the centre of the floor of the vehicle and, since it was a model of an actual vehicle, the fixation points of the plate are different to those used in this study

Summary

Introduction

The use of the improvised explosive device (IED) from insurgents against Coalition Troops and civilians has epitomised the recent conflicts in Iraq and Afghanistan. A significant number of injuries have been sustained by vehicle occupants during under-vehicle explosions in which the deformation of the floor of the vehicle subjected the lower limb to high-rate axial loading (Ramasamy et al, 2011c). Following detonation a shock wave propagates through the explosive instigating an almost instantaneous chemical reaction which produces hot, high-pressure gas that forms behind the detonation wave. This gas expands rapidly, and, if the explosive is buried, pushes material outwards from the surface, throwing soil ejecta up into the vehicle. On interaction with the vehicle the blast wave causes rapid deformation of the floor, causing axial loading to the lower limbs of occupants inside

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