A fragmentation assessment method for submerged charges

Explosive ordnance poses a threat to human life, local ecosystems and infrastructure. During the detonation of cased munitions, the rapid energy release from the chemical process is transferred to the surrounding material, resulting in fragmentation. This can cause additional damage on top of the air blast. During land ordnance disposal, these two hazard mechanisms are considered to ensure safe working distances of operatives and infrastructure. However, underwater ordnance clearance often omits or ignores the risk of fragmentation. This method may be justified when clearing ordnance in deeper seas, as fragmentation can only propagate so far within water. Nevertheless, most explosive ordnance disposal operations take place in shallow waters, close to shorelines or near critical maritime infrastructure - meaning a likelihood of fragmentation damage. This paper presents a series of experimental trials that compare both air and underwater cased explosive charges at various depths to investigate the characteristics and distribution of the associated fragmentation. Both high-speed videography and witness panels were employed to capture in-flight velocities and fragment distribution to improve safe working procedures for naval ordnance operations.