Implosion impact behavior and damage mechanism of titanium alloy pressure hulls under deep-sea conditions at submerged plate boundaries

When the deep-sea pressure hull is subjected to hydrostatic pressure exceeding its ultimate bearing capacity, it experiences a catastrophic underwater implosion. The resulting implosion shock wave exhibits an extremely high peak value and releases a significant amount of energy, posing a serious threat to the structural integrity of the entire submersible. It is essential to investigate the pressure hull implosion at the boundaries of adjacent structures in deep-sea environments. First, an experiment investigating the underwater implosion of a spherical pressure hull at a submerged plate boundary is conducted. Then, the arbitrary Lagrangian–Eulerian method is developed to study the implosion fluid-structure interaction characteristics of titanium alloy spherical pressure hulls under both variable-spacing and variable-thickness plate boundary conditions. The dynamic deformation and failure mechanisms of spherical pressure hull implosion, along with the impact behavior and damage mechanisms of submerged circular plates, are analyzed. The extent of the fracture in the spherical pressure hull decreases as the distance from the boundary increases. In addition, when the spherical pressure hull implodes at variable-spacing circular plate boundaries, the implosion center exhibits a significant migration effect.