EXPERIMENTAL DEVELOPMENT OF THE DYNAMIC SIMULATION METHOD FOR UNDERWATER STRUCTURES

A dynamic simulation method was developed in which a structure's experimental modal parameters in air are used to calculate its modal parameters in water, knowing only its external geometry. Dedicated software for the underwater simulation was written on the basis of a prior theoretical analysis. The simulation was conducted for underwater and verified experimentally, with excellent agreement of the simulated and experimental results. The effects of the thickness of the water enclosing the structure and those of the water pressure on the structure's dynamic behaviour were also examined. The test results showed that the structure's natural frequencies underwater decrease as fluid thickness increases, tending asymptotically to a value beyond which the variation ceases, and validated the theoretical predictions that the water pressure would in no way affect the structure's dynamic behaviour.