Hydroelastic Loading and Response of Ultra Large Container Ships

摘要

The importance of mathematical models for ship hydroelastic analysisgrows with the design of ever larger container ships which havespecific design and exploitation characteristics. Compared with othermerchant ships, they are characterized by relatively lower torsionalstiffness, which in combination with encounter sea states related totheir higher speed of approximately 27 knots can cause resonanceeffects. This paper is based on research activities and results of the EUFP7 project Tools for Ultra Large Container Ships (TULCS), withparticular emphasis to the part which deals with global hydroelasticloading and response. Special attention is paid to beam structural modelbased on the advanced beam theory. It includes shear influence on bothbending and torsion, contribution of transverse bulkheads to hullstiffness as well as an appropriate modelling procedure of relativelyshort engine room structure. Along with that, hydrodynamic model ispresented in condensed form. Further on, fully consistent formulationof restoring stiffness which plays important role in the hydrostaticmodel is described. Theoretical contributions are illustrated within thenumerical example which includes complete hydroelastic analysis of a11400 TEU container ship. The validation of advanced beam model ischecked by correlation analysis with the vibration response of the fine3D FEM model. Finally, ship hydroelastic response assessed bysophisticated beam model is compared with the results of fully coupled3D FEM + 3D BEM hydroelastic analysis. The obtained transferfunctions of sectional forces confirm that the developed model is veryuseful numerical tool for the designer and represents a reasonablechoice for determining wave load effects on ULCS, in early designstage.