Research On The Compution Of Slamming Loads On Hull Structures

Fluids/structures slamming problems are a common phenomenon in the field of naval architecture and ocean engineering. The local hull structure may suffer buckling failure because of slamming. Sometimes the instantaneous slamming pressure is so powerful that the hull produces deformation,even collapses. It is very necessary for the practical application to research the regulation of the hull slamming pressure in the working environment. In this paper, a lot of literature is refered to,and the concept of slamming,classification and the research progress in the field are introduced.In this paper,two kinds of methods,theoretical analysis and numerical simulation,are used to study the Fluids/structures slamming phenomenon and general law.Two types of slamming are defined again. The first kind of slamming has a feature that the water points have no initial velocity,like the wedge slamming into the water.The another kind of slamming has a feature that the water points have some initial velocity, like the wave slamming on the moving ship fore and aft.In the basis of the ALE algorithm, fluid-structure interaction of the 2D rigid wedge and plate entering into water is simulated using the finite element software ANSYS/LS-DYNA. Comparisons between numercial result and experimental results and SPH results show consistency.The structure into water problem of different speed,different materials, different thickness and different angles are analysised detailedly. And the numerical simulation results are discussed and analyzed.Then,based on the ship general strip theory, the numerical time domain method is used to present the ship motion, forecasting the relative position,the relative velocity and wave profile between the wave and ship motions. Due to the nonlinear effects of wave, it has a modification on the crest front steepnesses while a spectrum correction method is put forward. The relationship between the slamming and the rate of change of added mass on the structure surface is used to calculate the breaking waves slamming pressures of FPSO bows. The program is proved to be correct and reliable. This paper promotes the understanding of fluid-structures slamming problem and improves the method on the compution of slamming loads,some meaningful conclusions are drawn which are significant for some design of offshore engineering structure and naval architecture. At the same time,unsloved problems and further research direction are pointed out.