Material parameterization including damage for predicting diver lung underwater explosion (UNDEX) injury

A computational framework for predicting the mechanical response of the lung to underwater explosions (UNDEX) is presented that integrates anatomically informed finite-element geometry with carefully chosen constitutive descriptions and parameterization strategies. Consistent with the limited fidelity for the employed diver torso model which includes the lungs, diaphragm, and abdomen, but not the ribcage, emphasis is placed on creating a parameterization methodology for capturing the hyperelastic and hyperviscoelastic tissue behavior including damage. In order to circumvent the need for direct experimental testing on biological specimens, alternative parameter identification approaches are employed. Representative material properties are compiled from the literature and selectively refit to existing experimental datasets. Where data gaps exist, physically plausible values are adopted to preserve predictive utility. Injury and damage are quantified through asserted, quantitative mappings that relate clinically defined injury severities to spatial regions or percentages of affected lung tissue, enabling parameterized damage fields to be incorporated into blast simulations. Model validation is sought through available datasets. The resulting modeling capability is intended to inform operational protocols, stand-off distance criteria, risk assessments, post-event forensic analyses, and environmental impact evaluations (including marine mammal exposure) for a broad range of underwater blast and hydrodynamically propagated shock scenarios.