Studies On The Strength Problems Of A Heavy Lift Vessel With Single Hatch And Large Opening

Heavy lift vessel is one kind of special ships developed from the muti-purpose vessel. The entire ship inherently possesses low torsional rigidity due to its large opening deck structural configuration. The total hull torsion caused by oblique wave and Unsymmetrical cargo loading happens together with horizontal bending and vertical bending, which makes the hull torsional deformation and warping stress obviously. All kinds of hull simplified calculation model are not suitable for large opening ships, such as the bending equivalent beam model, cargo hold model and 3-D framework with two-dimensional plane model.Therefore,in order to get the detailed results of all the hull primary members'deformation and stress,it is necessary to make direct calculation of the whole hull's bending and torsion strength based on the global finite element model.According to the bending and torsion strength problems of a 10000DWT single hatch and large opening heavy lift vessel, hydrodynamic analysis and global finite element analysis method are adopted. Both the long term prediction of wave induced motion and random loading at sailing condition and the short term prediction of wave induced motion and random loading at working condition are performed by SESAM software system of DNV classification society ,based on which a group of design waves are defined. Then the deformation and stress distribution of hull structure under each equivalent design wave are calculated. At last the detailed informations of the whole ship's structural strength are obtained. There is certain reference value to structure design and strength analysis of this kind large opening ship.The whole process and the key technical issues of hydrodynamic analysis and global finite element analysis are described clearly in this paper. The analysis methods are valuable for other types of ships'structural strength analysis.