The Direct Analysis Method For Hydrostatics And Intact Stability

This paper presents a direct analysis method, based on finite element, for hydrostaticsand intact stability. The technique depends on modeling the surface of floating bodies withrigid elements, the hydrostatic pressure was loaded on the rigid body(the force exercised bythe hydrostatic pressure is buoyancy), all the degree of freedom of reference point was fixed,the reaction force of reference point is buoyancy.If the gravity was applied on the reference point of rigid body (or filled up the floatingbody with mass elements, after gravity field was applied, the gravity can be simulatedequivalently), the hydrostatic pressure was loaded on the rigid body, after the finite analysis,the rigid body could reaches a position of equilibrium, the displacements and rotational ofreference point is the information of floating state. In this case, change the rotationaldisplacement of reference point (change the inclination of floating body), the rightingmoments couled be figured out from the reaction moments of the reference point.The direct analysis method has been developed and implemented into commercial FEAsoftware ABAQUS, the cuboid’s floating state and stability was analyzed by this method, thefinite solution is in close agreement with analytical solution. After that the direct analysismethod was applied to the oil tanker、the large trimaran ship and semi-submersibleplatform.The obtained results showed that direct analysis method presented in this thesis issimple, effcient and robust in analyzing the floating state and intact stability, it can fulfillvarious degree of accuracy. The presented method, which is convenient and insensitive to theelement size, has a great performance at all kinds of ships and coastal structures especially atcomplicated conditions.