Study on the dynamic response mechanism of fluid-structure interaction in deep-sea titanium alloy pressure-resistant structures during underwater implosion
The outer surface of deep-sea titanium alloy pressure-resistant structures is subjected to high-pressure hydrostatic loads. When the structure undergoes damage or failure, a short-duration underwater implosion phenomenon with an extremely high shock wave peak can occur. Based on the arbitrary Lagrangian-Eulerian (ALE) method combined with the Johnson-Cook constitutive and failure models, this study investigates the fluid-structure interaction process and damage characteristics of the underwater implosion of deep-sea titanium alloy pressure-resistant structures. The accuracy of the numerical method is first validated by comparing the shock wave loads and collapse modes from underwater implosion experiments. Subsequently, the fluid-structure interaction mechanism, dynamic structural response, and energy evolution during the implosion of a titanium alloy spherical pressure-resistant shell are analyzed, revealing the physical mechanisms of structural failure under extreme-depth loading due to ultimate strength failure. Results indicate that the titanium alloy spherical pressure-resistant shell is completely destroyed into large fragments and small debris after implosion. The peak shock wave value at the same distance increases linearly with the hydrostatic pressure, but the growth rate gradually decreases with increasing distance.
