Rational Determination of Design Wave using Combined Design Load Parameters (DLP) on Semi- Submersible with Twin Pontoon Type

摘要

This paper proposes a new approach to determine and verify designwaves using the combined design load parameters (DLP) for semisubmersiblewith twin pontoon type, which can present the combinationof the split force with torsion or longitudinal shear force. Severalmethodologies have been used to select the combined DLP by someengineering companies and classification rules. However, there are fewexplicit statements of the back-up references of the methodologies usedon classification rules and the project specific reports provided byengineering companies.The comparison of newly proposed methodology and the existing three(3) methodologies has been implemented by the data of global load andresultant FE analyses. And an assessment has been followed to ensurewhether the structural stresses on the semi-submersible Hull can beconfirmed in accordance with classification rule and previous projectexperiences. In this paper, two combined DLPs are taken into account,one is defined as the case when longitudinal shear force and split forceare maximized as far as possible (longi. shear split) and the other is thecase when torsion and split force are maximized at the same time(torsion split). The two(2) combined DLPs could not be extracteddirectly by superposing corresponding linear RAOs throughhydrodynamic analysis.