Stochastic fluid—structure interaction of large circular floating islands during wind waves and seaquakes

The dynamic responses of an artificial large floating island subjected to wind waves and seaquakes are evaluated using both long-term and short-term stochastic descriptions of loading and stochastic response analysis of the linearized dynamic model. The short-term description is represented by the power spectral density functions of the load time history during each load intensity, whereas the long-term description is concerned with the recurrence pattern of all possible load intensities. The stochastic responses of the floating island, which are conditional on return periods of environmental forces, are evaluated by a stationary random vibration analysis, taking into account structurally flexibility and fluid structure interaction. Numerical examples are presented to discuss the dynamic behavior of the floating island with different mooring stiffnesses against both wind waves and seaquakes at different offshore sites.