A Study for Improvement on Structural Strength Assessment of Semi-Submersible Unit

摘要

Current offshore market pursues an extreme cost and schedule innovative business model and requests optimum design within tight project budget. This is also valid for semi-submersible unit.This paper discusses several widely adopted conservative assumptions used for semi-submersible unit hull design and proposes a reasonable strength assessment approach based on realistic procedure and Class rule requirement. Some engineering companies, therefore, suggest existing methodology which follows conservative approach with regard to global and local stress combination, normal stress derivation from load cases and observing area for result application. However, there are few explicit and logical references and current market leads to entire optimum design as long as reliable design against various design conditions are maintained.In this paper, the comparison between proposed approach and existing methodology is to be discussed, which given suggestion has practical characteristics with structural strength assessment point of view for semi-submersible unit. Consequently, the feasibility of the proposed methodology and resultant structural scantlings and weight are presented by comparison of the two (2) methodologies throughout mentioned stress extraction from FE analysis.