Structural analysis of node cut-outs in a semi-submersible offshore platform
Paper i proceeding, 2016

The connection between column and deck-box on a semi-submersible platform is often subjected to high stress concentrations that can be governing for the structural strength. One common design used to withstand the high stresses is a cast integral in high tensile material, which is both heavy and expensive to manufacture, which is why an alternative cut-out design is investigated. This study presents an analysis of a node connection with regard to yield stresses, buckling, fatigue damage, weight and cost in order to propose an alternative cut-out design using the same criteria. The cast integral, which is analysed as a reference case and used for comparison of designs, is of a typical design used today. A parametric study shows that the use of a cut-out design may be advantageous in the centre bulkhead connection between the column and the deck-box. The adjacent geometry is of simple character and the cut-out does not affect the overall structural design. The cut-out is found to be a feasible alternative to the cast integral, with yield stresses and fatigue damage in the same range. Further refinements of the cut-out design could, however, decrease both yield stresses and fatigue damage. A suggested cut-out solution leads to a decrease of 4.5% in weight for a reference structure. For the same reference structure the production cost is estimated to decrease by 9%, hence, the cut-out design is recommended for the centre bulkhead connection.

stress redistribution

stress concentration

semi-submersible

cut-out

cast integral

Författare

Jonas Ringsberg

Chalmers, Sjöfart och marin teknik, Marin teknik

Daniel Karlsson

Chalmers, Sjöfart och marin teknik, Marin teknik

Mårten Forser

Chalmers, Sjöfart och marin teknik, Marin teknik

Proceedings of the ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2016) in Busan, Korea, June 19-24, 2016

Vol. 3 10-

Ämneskategorier

Maskinteknik

Farkostteknik

Drivkrafter

Hållbar utveckling

Innovation och entreprenörskap

Styrkeområden

Transport

Produktion

Materialvetenskap

Fundament

Grundläggande vetenskaper

DOI

10.1115/OMAE2016-54068

ISBN

978-0-7918-4994-1