A collaborative grading optimization method of rib-reinforced ultra-thick composite pressure hull

With the service environment of underwater vehicles gradually moving to the deep sea, the high load-bearing requirements lead to an increase in the thickness of the composite pressure hull, which not only reduces the molding quality but also increases the difficulty of design. Thus, in order to improve the design efficiency, a collaborative grading optimization method for geometry and layup of rib-reinforced ultra-thick composite pressure hull is proposed. Firstly, the sensitivity analysis of geometric parameters on weight, stability and strength of the pressure hull are conducted based on approximate model technology, and the reinforcement efficiency of different configurations under different length to diameter (L/D) ratios of hull is compared. Secondly, based on geometric factors and approximate model techniques, the complex ultra-thick layup optimization is gradually decomposed into bearing characteristics analysis, optimization of ply ratio, ply thickness and ply sequence. Finally, the results show that when the L/D ratio of the hull is less than 3, the hat-shaped rib has the best reinforcement efficiency, while the total thickness of the hull is large. Otherwise, the I-shaped rib is better. Compared with the mono-shell, the buoyancy factor of the optimized rib-reinforced configuration is reduced by 41%.