Influence of wood core on the mechanical performance of sandwich composite submersible pressure hulls

This investigation aimed to determine the feasibility of fabricating a pressure hull using wood-sandwich composites to achieve significant weight reduction compared to steel. Five wood types, bamboo, paulownia, balsa, mulberry, and engineered mulberry, were analyzed. A parametric study was conducted to minimize weight and enhance stability under hydrostatic loading. The design of the sandwiched composite pressure hull depends on laminate layers, fiber angles, material system, thickness of the face sheets and core. This task presents a parametric design analysis to find out the optimized design for a pressure hull submerged under hydrostatic pressure by means of Finite Element Analysis (FEA). Material failure criteria were used to examine the failure of composite face sheets. Overall stability was examined using the buckling factor and maximum stress (MS) failure criterion. Various composite materials face sheets were employed, and numerous kinds of woods were implemented as a core with angle configuration of [0_m/90_n] and [45_m/-45_n]. The angle configuration of [45₁₄/-45₁₄]₂₈ with Paulownia core and CFRP face sheet, shows the minimum weight of 11,338 kg, which is less than around 20,000 kg of conventional steel pressure hull. The values of FS_TW, FS_TH , and λ were recorded 3.20, 2.43, and 1.44 respectively, with a von Mises stress of 160.75 MPa. The thickness of each face sheet and core was obtained 56 mm and 140 mm respectively. Achieving a 40–45% weight reduction compared to a steel hull, while fully satisfying all safety requirements, thereby confirming the feasibility of using wood-core composites for deep-sea pressure hull applications.