INVESTIGATION OF COMPOSITE SURFACE EFFECT SHIP (SES) HULL STRUCTURE UNDER HYDRODYNAMIC LOADING USING FLUID-STRUCTURE INTERACTION

摘要

An investigation of the deformation and structural analysis of composite hulls of surface effect ships (SES) under wave loading is undertaken. The analysis is carried out using finite element analysis (FEA) and by introducing fluid structure interaction (FSI). FSI is introduced in the analysis in order to couple structural deformation with fluid-field which in turn affects the load in the structure. Since deformation in ship structure is large, it is expected to change the flow field significantly. If accuracy in design and analysis is required, interaction between structural deformation and corresponding change in flow-field must be considered. The hull structure is modeled using traditional FEA approach and then loaded at the wetted surface by the prescribed wave loading related to various sea states. This approach results in a system of equation that uses displacement degree of freedom (d.o.f) of the structure and pressure d.o.f at nodes of the wetted surface. Fluid domain is modeled by elements that have displacement d.o.f. Kinematic conditions at the fluid-structure interface are defined as equality of displacements and action-reaction principles. FSI analysis is implemented through commercial FEA code, ANSYS by using their CFX module. A two-way coupling is considered in the CFX module in which at defined intervals the predicted fluid forces on the hull structure are communicated to the solid analysis and the hull displacement and velocity are communicated in return. Details of FSI analysis along with the studies of deformation and stresses in the composite hull are described in the paper.