In English

Use of Corrugated Shell Plating in Semi-submersible Offshore Platforms - Study on exploring strength, weight and manufacturing implications of replacing the stiffened shell plating with corrugated panels

Md Asaduzzaman Sarder ; Hüseyin Sağlam
Göteborg : Chalmers tekniska högskola, 2011. 81 s. Report. X - Department of Shipping and Marine Technology, Chalmers University of Technology, Göteborg, Sweden; 251, 2011.
[Examensarbete på avancerad nivå]

The deck load capacity of new offshore platforms is increasing as these marine structures continue to increase in size. As a consequence, the structural weight has become a concern. The current investigation contributes to a solution of a more weight-effective structural design of shell-plated marine structures. The structural weight of a shell-plated structure can be reduced in various ways. In the current investigation, an alternative design is presented by means of a corrugated structure. By the introduction of corrugated panels, a structure may be constructed lighter and cheaper compared to traditional structures with stiffened panels. The welding work during manufacturing can also be reduced substantially. Even though the idea of using corrugated shell plating has been practiced in various applications for a long time, such as in corrugated bulkhead and deck plating, it is yet unexplored in shell structures. Thus, the aim with this study is to compare corrugated shell plating with conventional stiffened panels with respect to strength, weight and cost. A methodology is presented where various solutions are analyzed and compared with regard to strength characteristics, weight and cost. Here, strength characteristics include ultimate tensile strength, buckling stability and fatigue life calculations. Detailed numerical analyses are presented using a realistic and reasonable area of a panel structure of an offshore platform. The structure analyses are carried out using linear finite element analyses. A number of design criteria have been evaluated and verified by comparing predictions obtained in an extensive parametric study of basic structural strength following classification rules. Two alternative designs with corrugated shell plating are proposed with respect to corrugation symmetry. The first one had unequal flanges and the same thickness as that of the reference stiffened model. The second had equal flange lengths. The weight reduction values achieved using these designs were 38 percent and 59 percent in shell plating, respectively, compared with a reference model for traditional stiffened shell plating. The study concluded with a reduction in production costs by 35 percent and 49 percent, respectively. The investigation clearly demonstrates that corrugated panels are often favourable for lightweight design and manufacturing robustness of marine structures.

Nyckelord: corrugated panel, lightweight design, fatigue, buckling, ultimate limit state, cost, finite element analysis, parametric study, optimization.

Publikationen registrerades 2012-08-28. Den ändrades senast 2013-04-04

CPL ID: 162668

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