Experimental and numerical investigation of a hollow cylindrical water based barrier against internal blast induced fragment loading

A hollow cylindrical water-based barrier was applied to dispose of an improvized explosive device (IED), and the mitigation effects of the barrier on the multi-fragment loading were experimentally and numerically investigated. Seven in-situ internal explosion tests were performed on the barriers based on pure water or water and fiber layer by detonating an IED containing a 500 g TNT and 454 g steel spherical fragments. The effects of blast loading on the anti-fragment performance and dynamic response of the barrier were studied by changing the barrier's inner diameter or adding a water cover. Numerical models for a water barrier corresponding to the experiments were established and validated. More extensive parametric studies were carried out using these models. The blast loading weakened the anti-fragment performance of the barrier, especially for an on-ground detonation, corresponding to an increase in the fragment residual velocity of up to 20%. However, on an equal mass basis, the anti-fragment performance of the barrier benefits from a smaller inner diameter because the increase of the wall thickness had stronger effects than the enhanced blast loading, consistent with the experimental findings. Both the experiments and simulations demonstrated that adding a water cover on the barrier barely affected the anti-fragment performance because the blast wave reflected by the cover loaded the barrier from the barrier's top to its base, which led to a significant increase in the kinetic energy of the barrier after it was perforated by most of the fragments.