The Structure Strength Research Of Ultra-large Container Ship

According to the prediction of Britain Ocean Consulting Company, the annual growth rate of container throughput will be up to 80% from 2007 to 2010 which means the total throughput of container will exceed 600 million in that time. Right under this condition, the ultra-large container ships attract the eyes of the whole shipping industry because of their surprising container capacity, efficient management and relatively lower cost. However because of the large opening which may exceed to 85% of its breadth, it brings a series of strength problems to ship designers.This paper focuses on the torsional strength and the fatigue strength of hatch corner of ultra-large container ships. As for the torsional strength, first, putting forward three different measures to improve its torsional strength based on their structural characteristics and torsional property. After that, the Germanischer Lloyd finite element software POSEIDON and ANSYS were applied for building the finite element model and doing calculation respectively. And the last, the best way to enhance the torsional strength of ultra-large container ship was recommended.In addition to this, this paper has also performed some research in the transition form and fatigue life of hatch corners. Using sub model technique of the ANSYS and applying nodal displacement extracted from the 3 holds ship model as the boundary conditions to the hatch corner model. Some truss elements with very small sectional area were also applied to the hatch corner edge to get the stress distribution accurately and conveniently.Three mostly used transition forms were discussed including circle transition, elliptical transition and key hole transition. Changing their geometric parameters (radius, the ratio of major and minor axis) to get the relations between these geometric parameter and fatigue life of the hatch corner. Each of transition forms has been given the best value range which means in this range the ship will have a improved fatigue life. And at last, formulas were fitted based on the calculation results according to the specified loading conditions which can be also a reference for the similar ship design.