REDUCING HYDROELASTIC RESPONSE OF VERY LARGE FLOATING STRUCTURE USING FLEXIBLE LINE CONNECTOR AND GILL CELLS

摘要

This paper investigates the effects of flexible line connector and gill cells on reducing the hydroelastic response of pontoon-type, very large floating structure (VLFS) under wave action. Gill cells are compartments in VLFS with holes or slits at their bottom surfaces to allow water to enter or leave freely. They are modelled by eliminating the associated hydrostatic buoyancy forces. In the hydroelastic analysis, the water is assumed to be an ideal fluid and its motion is irrotational so that a velocity potential exists. The VLFS is modelled as an isotropic plate according to the Mindlin plate theory. In order to decouple the fluid-structure interaction problem, the modal expansion method is adopted for the hydroelastic analysis which is carried out in the frequency domain. The boundary element method is used to solve the Laplace equation for the velocity potential, whereas the finite element method is employed for solving the equations of motion of the floating plate. It is found that by appropriately positioning the flexible line connector and gill cells, the hydroelastic response and stress resultants of the VLFS can be significantly reduced.