Four impulse noise auditory injury criteria adopted by NATO countries, namely, the MIL-STD-1474D (USA), Pfander (Germany), Smoorenburg (Netherlands), and L(Aeq8) (France), are evaluated against human volunteer data. Data from subjects wearing single-hearing protection exposed to increasing blast overpressure effects were obtained from tests sponsored by the US Army Medical Research and Material Command. Using logistic regression, the four criteria were each correlated with the test data. The analysis shows that all four criteria are overly conservative by 9.6-21.2 dB for the subjects as tested. The MIL-STD-1474D for single-hearing protection is 9.6 dB lower than the observed injury threshold for 95% protection with 95% confidence for this particular group of subjects as tested. Similar conclusions can be drawn for the other three criteria.

The complex interaction between underwater explosion bubbles and nearby structures is studied using two-fluid computational fluid dynamics. Gravitational effects on bubble jetting are significantly different between jet-up and jet-down orientations. This paper presents computational results of underwater explosion bubble dynamics near a disk and a sphere. The results show that the bubble jetting and collapse phenomena and the consequent pressure loading are affected by the structure’s shape, the orientation of the bubble to the structure, and the bubble depth. A unifying notion emerges connecting jet strength at impact to bubble curvature at the time of jet formation. [S0098-2202(00)01804-6]

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