An Optimized Configuration of an Enclosure Structure for Safe Containment of Internal Blasts,
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Large deflection elastic-plastic response of a hemispherical containment shell configuration clamped to a horizontal rigid foundation and subjected to an internal blast was analyzed using a finite-difference structural response code PETROS 3 5. The reflected overpressure peak was estimated from a scaled distance of the wall from the point of detonation based on a conservative cube root scaling law and an exponential decay given by the modified Friedlander equation. The residual quasi-static overpressure was obtained from an equation developed by Kinney and Sewell based on the ratio of the available vent area and the internal volume. The results indicated the initiation of flexural waves at the boundary propagating towards the pole and converging thereby altering the spherically symmetric breathing mode of response of the centrally loaded hemisphere. The peak deflection predicted by the code occurred at the pole and permanent deflection was found to be quite small after releasing the load. Transient strain components at the inner and outer surfaces near the clamped edge due to largely elastic oscillations showed the effect of bending deformation superposed on the membrane components. In conclusion the protective structure was found to be efficient and cost effective and capable of blast containment with an adequate margin of safety.