Structural Optimisation of Submarine Pressure Hulls : Optimisation using Finite Element Method with respect to Weight, Cost, Fatigue and Buckling

Sammanfattning

This thesis covers the development of an optimisation method for submarine pressure hull structures using parameterised finite element models. The method combines fatigue and buckling constraints with mass or cost minimisation to identify optimised designs. The study shows how operational requirements, such as different diving profiles, influence the dimensions of the obtained optimal geometry and the governing failure mechanism. In many cases, buckling governs the design, while fatigue becomes more critical for higher strength steels and certain diving profiles. The response surface-based optimisation method sufficiently captures the design space and enables a fast evaluation of multiple design alternatives. Furthermore, the developed program is modular, allowing variation of base geometry and refinement of individual sub-methods, such as the fatigue or buckling evaluation without changing the overall optimisation routine.