A Study on the Hydroelastic Response of a Large and Long Floating Offshore Structure and Behaviors of its Mooring System in Directional Spectrum Waves

Abstract

The hydroealstic response of a large, long, floating offshore structure moored in short-crested waves by tensioned tether buoys is studied. The applied model is a psuedo-elastic body connecting each rigid unit part at the deck with elastic members. The main concern of this paper is the distribution of vertical displacement in short-crested waves. The deflections of the deck part among regular waves are calculated based on a combination of modal analysis and hydrodynamic force analysis and the results compared with measured values at multi-points. The deflections in short-crested waves are discussed through experimental results and theoretical predictions. The response spectra and distributions of variance of vertical displacement along the centre line of the structure are shown for both long and short-crested waves and the influence of flexibility on deflection is discussed. The motion of a TL-buoy and tether tension for the case of a single buoy and a buoy moored to a structure are also investigated. The interactions between buoy and structure are discussed for the realization of a mooring system for a large and long floating offshore structure.