Effect of stand-off on near-field blast mitigation provided by water-filled containers

Water-filled containers placed externally on an armored vehicle offer a potentially low cost, light-weight, and simple technique to mitigate near-field explosive blast, although the use of a gap or standoff between the container and target has not been studied. This paper uses experimental testing and numerical simulations to characterize the influence of this container standoff on the mitigation of near-field blast effects. The addition of the container standoff was not found to generally increase the blast mitigation effect provided by water-filled containers on the deformation caused to a steel target plate. While the container standoff was found to enhance the spreading and shadowing blast mitigation mechanisms provided by the water-filled container, this was offset by an increase in blast loading due to the container being closer to the explosive charge. A new mitigation mechanism was identified as the time delay between the initial loading of the steel plate by the blast wave and the subsequent impact of water ejected from the container. The results from this work provide engineers guidance into the design of water-filled containers for near-field blast protection of armored vehicles.