| Summary: | 博士 === 國防大學中正理工學院 === 國防科學研究所 === 93 === Since ancient times, man has had the desire and the need to penetrate aquatic environments for military, scientific, and recreational purposes. In pursuit of these activities, he has developed an amazing array of underwater vehicles. The hull with the lowest weight to buoyancy ratio for a given depth is advantageous since the remaining weight can be applied to increase payload, diving depth, propulsion, endurance, and meet pressure hull structure’s safety. Accordingly, the purposes of this thesis are to investigate a novel multiple intersecting spheres (MIS) pressure hull.
This study investigates the optimum design of a MIS deep-submerged pressure hull subjected to hydrostatic pressure, using a powerful optimization procedure combined the extended interior penalty function method (EIPF) with the Davidon-Fletcher-Powell (DFP) method, structural failure, spatial and human engineering requirements are considered to minimize the buoyancy factor.
The results reveal that the shell thickness is most important to lobar buckling strength, and that rib-ring width, rib-ring inner radius and spherical shell intersection angle are most important to rib-ring hoop strength. However, for the HY80, HY100, HY140 and Ti-6Al-4V alloy optimal MIS pressure hulls, the higher weight/volume ratio implies a larger diving depth and the higher yielding strength/density ratio implies a better structural efficiency. Based on the same pressure hull material, length, and diameter for both cases as the design criteria, results reveal that the structural efficiency of the traditional stiffened cylindrical pressure hull is superior to MIS pressure hull at any operating depth.
Design approaches and results presented in this thesis not only provide a valuable reference for design of future underwater vehicles but also will be applied to the design of submarine structures in future.
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