Investigation Of Slamming Loads For Fpso In Ship Model Tank

In this work the dynamic response of an FPSO to slamming loads in extreme waves was studied by experimental method. This study focused wave loads and pressure distribution on the bow of an FPSO. The whole experiments to obtain the FPSO motions and sea loads were carried out in the Hydrodynamics Laboratory of University of Glasgow with a 1/80 scale model of Schiehallion FPSO in both fully loaded and ballast conditions. Since the aim of the tests was to measure the longitudinal forces and the peak pressures on the bow, a segmented model was designed and constructed. The model consists of three horizontally segmented bow region followed by four vertical segments. Some pressure transducers were located at the bow region to measure the peak pressure during the tests. And some strain gauges were located on the main spine beam to investigate the hull girder bending moment, and the bow section to measure the horizontal and vertical forces on each segment of the bow. During the tests the "New Wave" was introduced into the tank for the simulation of extreme waves. The concept and realization in the tank of the "New Wave" were discussed in this thesis. Based on this theory some highest waves, different front steepness waves and maximum bending moment waves were generated in the tank. And at the mean time some random waves have also been run. Based on the results from the tests, a prediction of the pressure during impact was concluded. It is recommended to treat the breaking and non-breaking wave separately when calculating the impact loads. For calculating the horizontal force during the impact the horizontal particle velocity and vertical velocity of water surface (immersion velocity) should be used. And for non-breaking wave the horizontal particle velocity can be estimated by using regular wave theory. For breaking wave the horizontal particle velocity can be taken as the wave celerity, since the wave is breaking when horizontal particle velocity is equal to or larger than the wave celerity. The vertical velocity of water surface is estimated by wave celerity. This methodology needs to be validated by more experimental work.