Objectives This study investigates the implosion response characteristics and protective effects of deep-sea composite pressure-resistant spheres under various working conditions.

Methods  First, the arbitrary Lagrangian-Eulerian (ALE) method was employed to simulate the fluid-structure interaction process during the implosion of deep-sea composite pressure-resistant structures. The effectiveness of the numerical method was then validated by comparing the results with those from typical underwater implosion experiments. Subsequently, a parametric analysis was conducted to gain a more comprehensive understanding of the implosion response characteristics of the composite pressure-resistant structure. Numerical simulations were performed to study the implosion of composite pressure-resistant structures under various working depths, implosion trigger directions, and numbers of implosion triggers, with their influence patterns analyzed. The effect of wall thickness of the pressure-resistant structure on external conditions was also investigated. Finally, the similarities and differences in the impact of various factors on the response characteristics of ceramic and composite structures were compared.

Results The working depth has a significant impact on the implosion response characteristics of composite pressure-resistant structures. As the working depth decreases, both the intensity of the structural response and the peak value of the flow field pressure are notably reduced. At the pressure monitoring point located one radius from the center of the sphere, the peak values were reduced by 63.3% and 71.7%, respectively. For structures with relatively thin wall thickness, the degree of this reduction becomes less pronounced. The implosion trigger direction and the number of implosion triggers have a negligible effect on the implosion response of the composite pressure-resistant structure.

Conclusions This study reveals the implosion response characteristics of deep-sea composite pressure-resistant structures under varying external conditions. The findings provide valuable insights for the design of underwater implosion protection systems and their engineering applications.