| Floating structure's coupled dynamic analysis has been the focus in ocean engineering field. The interaction between platform and flexible members doesn't only impact the buoy's motion, but the wave loads on it. A coupled dynamic analysis was investigated in this dissertation, considering the mooring lines and risers' impacts. The contents of this paper are as follows:1) A boundary integral equation based on mixed source/dipole distribution was adopted to calculate unsteady disturbance potential, and a matching method was presented by using FE meshing tools to mesh BE. The hydrodynamic coefficients of a floating sphere and a floating box were calculated by this method, and the results were compared with the data computed by Hydrostar.2) Drift forces were calculated based on far field integration method, and the formula of QTF was derived, which could consider the effects of incidence, diffraction and radiation.3) The effect of mooring system is transformed to stiffness, and the effect of riser system is transformed to damping. The complete mooring stiffness is derived based on catenary theory, and the contribution of drift motion to the change of stiffness was investigated. For flexible risers, the effects of stiffness on each region are different, so an equivalent girder model was built, which could be used to calculate the riser damping.4) Finally, a coupled pattern was presented, drift motion changes the mooring stiffness, the change of stiffness impacts the platform's motions, and the drift force calculation is on the basis of motions.
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