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In the last years, offshore industry has become into one of the most innovative and profitable industries all over the world. Due to its high complexity requirements and the huge number of technologies involved, this industry is now a vast ocean where young engineers can dive in search of new knowledge and opportunities to contribute to the development of the engineering. 

Some of those technologies involved in offshore industry are special portable devices designed to transport special equipment from the shore to offshore facilities. In addition, different international organizations have been developing design codes for steel structures in the last years. However, how similar are these codes? Are there significant differences between them? 

A comparative analysis between five offshore design codes (API, DNV, Eurocode, ISO and Norsok) has been carried out for a portable offshore unit in this master thesis. DNV software and different codes and standards have been available to accomplish this task and try to get to a conclusion. To do this, several analysis in different scenarios were done to have a wide enough range of results and be able to do an accurate study of the situation. 

Clear and solid conclusions have been got for these codes and a “pattern of behavior” has been determined for all of them. Results show that one of the codes is very conservative in it results, with differences from 40% up to 190% of it values. Furthermore, some ideas for future research in this topic have been proposed.

Ingénierie, informatique & technologie > Ingénierie civile

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During fabrication process, material deformations are likely to occur due to various factors such as heat during steel cutting, welding induced deformations, lifting and turning of ship sections, temporary stiffening and other possible modifications of ship sections. Lifting induced deformations is one of the major causes of deformations that highly affect the production cost and quality. The aim of this thesis is to outline the main causes of deformations that occur in ship sections during fabrication and to analyse in detail the lifting and turning operations of one ship section using the Finite Element Method (FEM). A strength check using the FEM has been performed on the selected ship section to investigate the deformations and stresses in two different cases with three different loading conditions. First, the section has been analysed without temporary stiffening in three load scenarios: lifting before turning, worst-case scenario during turning and lifting after turning. Similarly, the second case study has been analysed but with the temporary stiffening added according to the lifting plan. Various influencing parameters that determine the lifting plan has been investigated such as the sling angle which directly affects the deformation characteristics. It is observed that the addition of temporary stiffening is essential to minimize the deformations and to maintain the stress levels below the yield point.

Finite Element Method, FE Analysis, Structural analysis, Lifting simulation, Hoisting simulation, FEMAP, Ship section, Ship block, Deformations, Sling angle. --- Ingénierie, informatique & technologie > Ingénierie mécanique