Critical details design for a deep-sea transparent manned cabin

Transparent polymethyl methacrylate (PMMA) cabins can provide superior observation capabilities for marine operations. However, conventional design standards, rooted in empirical methods inadequately address the challenges of interface deformation coordination at PMMA-metal penetration connections. This study undertakes an investigation into the critical design parameters that influence deformation coordination and structural reliability. A benchmark spherical PMMA cabin designed for 1000 m depth was analyzed, focusing explicitly on interface deformation coordination under varying design conditions, including gasket presence, gasket thickness angle variations (2.5°–6°), and friction coefficient variations (0.10–0.30). Results demonstrate that the incorporation of a nylon gasket significantly enhances the deformation compatibility between the PMMA cabin and metal penetrations, resulting in a reduction of peak maximum principal stresses approximately by 11.6 % and leading to a substantial decrease in interface damage accumulation following repeated deep-sea cycles. Increasing the thickness angle of the gasket from 2.5° to 6° further enhances deformation uniformity, reduces stress concentrations by nearly 9.6 %, and decreases cumulative fatigue damage by approximately 43 %. Furthermore, maintaining interface friction coefficients of less than 0.15 has been shown to facilitate microslip at the interface, thereby significantly mitigating fatigue damage by preventing severe shear stress localization. This study establishes that prioritizing deformation coordination through targeted interface design.