Design procedure for corrugated structures in cargo ships

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Volume Title
School of Engineering | Master's thesis
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Date
2012
Major/Subject
Laivanrakennusoppi
Mcode
Kul-24
Degree programme
Language
en
Pages
iv + 58 s. + liitt. 22
Series
Abstract
Corrugated bulkheads are commonly utilized structures in cargo ships. They can contribute up to 30% of the total steel weight of the cargo area constructions. Therefore, the design of the bulkheads is a vital issue in the concept design process. However, currently no efficient tool exists to guide this process. The classification society rule calculations for corrugated bulkheads have limited accuracy due to the varying rigidity offered by the surrounding structures. FEA is in general not used in the concept phase due to the large amount of work required for preparing an FE model. Thus, the designs are typically accomplished by referring to previously built vessels. In this thesis a method for designing and optimizing corrugated structures in pursuit of lower weight is derived. The optimization procedure is founded on direct strength analysis and constrained by CSR rules, defining initial scantlings limitations and FEA requirements. The optimization procedure development includes a study of the possibilities for conducting FEA on local structures in the concept design phase by utilizing an initial 3D product model. In addition, the feasibility of optimizing corrugated structures with algorithms available in the applied product model environment, i.e. optimizing with a deterministic algorithm (conjugate gradient algorithm) in relation to a probabilistic one (simulated annealing algorithm) is investigated.
Description
Supervisor
Romanoff, Jani
Thesis advisor
Ekqvist, Oskar
Naar, Hendrik
Keywords
corrugated bulkhead, concept design, FEA, optimization, CATIA
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