Study On Residual Ultimate Strength Of Large Container Ship In Fire

Containers with dangerous cargo cover a certain proportion in the maritime transportation,which always set a container ship on fire.Once the containers with inflammable,or explosive goods are caught in fire,the temperature of the nearby structures will rise rapidly.The mechanical properties of steel in high temperature drop sharply and even lose the bearing capacity,which leads to the reduction of the ultimate strength of hull structure.Therefore,the influence of high temperature environment on hull structure needs be considered,and analyzing the residual ultimate strength of the container ship in fire is vital.In this paper,the methods and progress of research on ultimate strength are briefly summarized,and the basic theory and status of research on temperature field in ship and offshore structure are introduced.On this basis,the basic theory and principle of nonlinear finite element method to calculate the ultimate strength are highlighted in the paper.The influence of calculation method,model range and loading rate on the accuracy of calculation results is analyzed by the example of a 10000 TEU container ship.And the appropriate analysis method and finite element model are obtained in the final.The fire model in ship is established considering the theory of temperature field analysis and the structural characteristics of container ship,and the temperature field distributions under different fire conditions are analyzed.Then,the influence of fire on residual bending ultimate strength(hogging and sagging)of container ship is systematically analyzed,and the relationship between location and duration of fire with residual vertical ultimate strength of hull structure is summarized.The stress state of ship structure under biaxial bending moment is simulated considering the combined action of vertical bending moment and horizontal bending moment in ship’s navigation.The influence on ultimate strength is fingered out by analyzing location and duration of fire,and the stress state of structure as well.At last,the relationship between above factors and the residual ultimate strength of hull structure is summarized.