Local plastic deformation prediction of spherical and cylindrical pressure hulls subject to underwater shock loading

Abstract

Pressure hulls of underwater vehicles, typically configured as spherical or cylindrical structures, are vulnerable to localized damage when subjected to shock loads from underwater explosions. This study establishes theoretical models for deformation patterns and deformation center deflection of such hulls under underwater shock by integrating fluid–structure interaction theory, localized deformation mechanics, and structural dynamics. Systematic investigations are conducted to evaluate the influence of hull thickness $h$, diameter $D$, length $L$, shock factor $I$, and hydrostatic pressure $p_{\infty }$. The deformation center deflection $w_0$ is found to scale as $w_0\propto h^{-2}$ with thickness, $w_0\propto \sqrt{D}$ with diameter, $w_0\propto L^{-0.5}$ with length, $w_0/D\propto I^2$ with shock factor, and $w_0/D\propto p_{\infty }$ with hydrostatic pressure. Results show that spherical hulls of equal diameter exhibit superior shock resistance, and hull thickness plays a particularly significant role in mitigating shock effects. The proposed deformation patterns and deflection metrics provide a practical basis for evaluating shock resistance and assessing pressure-bearing capacity and implosion risks in damaged underwater hulls.