傳統圓筒加勁型壓力殼與多球加勁型壓力殼結構強度比較之研究

A Comparative Study of Structural Strength between Optimum Traditional Stiffened Cylindrical Pressure Hull and Optimum Advanced Multiple Intersecting Spheres Stiffened Pressure Hull

傳統圓筒加勁型壓力殼與多球加勁型壓力殼為先進國家較常採用的兩種構形，本論文之目的在進行水下載具傳統圓筒加勁型與先進多球加勁型壓力殼兩種構形之最佳化設計的比較分析。採用相同壓力殼材料、長度以及直徑作為兩者共同的設計基準，針對兩種不同構形壓力殼特有的設計理念，在不同潛深之靜水壓負荷下，滿足壓力殼材料及結構的強度要求，同時符合人因工程與空間需求限制，以整體壓力殼結構之最小浮力因子為設計目標，作為評估兩種構形整體壓力殼結構效率之性能指標。並採用線性外延內罰函數法（linear extended interior penalty function method, EIPF）結合DFP變尺度法（Davidon-Fletcher-Powellvariable metric method）作為兩種最佳化構形模式的求解法則。在各種不同的操作潛深下進行兩種不同壓力殼構形最佳結構效率設計之擇優評估，同時探討操作潛深對兩種不同壓力殼最佳結構強度因子效應之關係。由本論文之研究結果顯示，在壓力殼結構效率部分，最佳傳統圓筒加勁型壓力殼均較優於最佳多球加勁型壓力殼；在壓力殼結構初始破壞行為方面，傳統圓筒加勁型壓力殼結構初始發生之破壞模態為兩肋骨中間處之殼板降伏失效，而多球加勁型壓力殼結構初始發生之破壞模態為加強肋降伏失效；在壓力殼結構承受靜水壓負荷之設計考量上，傳統圓筒加勁型壓力殼結構較易發生肋骨挫曲、半球形殼挫曲以及殼板局部挫曲等破壞，而多球加勁型壓力殼結構則較易發生加強肋降伏、殼板局部挫曲等破壞。研究成果希能為潛艇壓力殼設計之參考。 Based on the same pressure hull material, length, and diameter for both cases as the design criteria, this paper concerns with optimum designs of traditional stiffened cylindrical pressure hull and advanced multiple intersecting spheres (MIS) stiffened pressure hull subjected to structural buckling strength constraint, material yielding strength constraint, spatial and human engineering requirement constraints under hydrostatic pressure. The present optimal design problem involves determining the best structural configuration to minimize the buoyancy factor of the pressure hull. A powerful optimization procedure combined the EIPF method with the DFP method to solve the present nonlinear constrained optimization design problems of the traditional stiffened cylindrical pressure hull and MIS pressure hull in this work. Results reveal that the structural efficiency of the traditional stiffened cylindrical pressure hull is superior to MIS pressure hull at any operating depth; the first failure mode of the stiffened cylindrical pressure hull is the shell plating yield at midbay and the first failure mode of the stiffened MIS pressure hull is the rib-ring yielding; the frame instability, the dome shell buckling, and the shell lobar buckling must be firstly considered on the optimum design of the stiffened cylindrical pressure hull and the rib-ring yielding, the shell lobar buckling must be primarily considered on the optimum design of the stiffened MIS pressure hull.