Metal rupture from near-field underwater explosive bubble jetting at high hydrostatic pressure

The interaction between a gas bubble resulting from an underwater explosion event and a nearby structure under high hydrostatic pressure has been explored experimentally and computationally to assess the damage potential of such events on submerged structures. This study analyzed two flat plates with differing material properties: a relatively rigid steel plate and a more compliant thin aluminum plate, under varying explosive standoff distances and hydrostatic pressures. Standoff distances were selected relative to the explosive bubble’s maximum radius at the specified hydrostatic pressure to standardize interaction dynamics. High-speed photography was utilized to capture the interaction between the bubble and plate specimens and document the ensuing structural deformation for subsequent analysis using three-dimensional digital image correlation techniques. Computational simulations were conducted using the fully coupled Eulerian-Lagrangian fluid-structure interaction code, DYSMAS, which was pivotal in complementing the experimental findings. These simulations predicted the complex jetting dynamics of the bubble, including its shape, migration, and jetting behavior, as well as quantifying the resultant deformation and damage to the studied structures. The results reveal that variables such as the explosive standoff distance, plate rigidity, and hydrostatic pressure critically influence the bubble’s behavior, and the extent of damage inflicted on the nearby structure. Specifically, the study underscores the explosive bubble’s collapse and the accompanying jetting phenomena as primary contributors to the observed structural damage, including rupture, under the examined parameters. This study offers a deeper understanding of the mechanisms driving damage in submerged structures subjected to near-field UNDEX events.