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In a design process of floating structures, like ships and offshore structures, hydrodynamic analysis of wave-structure interaction is the first important key step.  Rigid-body based seakeeping analysis approach is applied successfully for this kind of analysis for many decades, but suffering its failure on some of latest mega-ships, like a container ship over 400 meters in length.  It has been found that the computed fatigue life of a large container ship based on a rigid-body hydrodynamic approach is significantly longer than the observation.  The elastic-body based analysis approach is raised to the stage for the interaction of water waves and elastic structures.  An ultimate hydroelasticity solution comes from CFD approach, but it is too expensive to be applied in routine work, because the number of regular wave cases needs to be analysed will be in general 3,000 to 5,000 in a design process, the number of combination of ship speed, wave headings and sea states will be a few hundreds and leads to simulation over hundreds of thousands of hours of real time.  The boundary element type of hydroelasticity models remain as the routine tool.  In this paper, general approach of 3D hydroelasticity is presented.  The differences between the rigid-body approach and hydroelasticity approach are discussed.  We also look into theoretical details of frequency domain hydroelasticity model orientated for low and moderate sea conditions, and that of time domain hydroelasicity model orientated for high sea states.  These discussions give a guidance of hydroelsticity application in marine and offshore industry.

Hydroelsticity, wave-structure interaction, frequency domain, time domain