Research On Load Carrying Capacity Of Ship Structure Considering Temperature Effect

Under the influence of global warming,the north and south poles have ushered in a new round of development,and the exploitation of the Arctic waterway has become a reality.Some countries and regions have turned their attention to the development of resources in the Arctic.After “the Belt and Road” initiative being put forward,the “Ice Silk Road” has also begun to build,which plays an important role in China's participation in the development of oil and gas resources in the Arctic region.It also means that more and more ships will be sailed to the polar regions.Owing to the fact that the Arctic Ocean is covered by thick ice,the passing performance requirements of the ship are relatively rigid.According to the statistics from the Russian Oriental Station,the lowest temperature in the Arctic is-68 °C,so the primary concern facing the development of polar sailing ships is the harsh low temperature and ice load environment.So far,there are some research results have indicated that low temperature will weaken the tenacity of steel and strengthen the yield strength and ultimate strength of steel.The research work on the ultimate strength of ships is mainly about ships in normal temperature environment.If the existing research results are directly applied to the evaluation of the ultimate strength of hull structures in low temperature environment,hazards may unpredictably occur.Therefore,this paper will combine with the experimental analysis,finite element simulation analysis,common specification,etc.to study the influence of low temperature environment on the ultimate bearing capacity of hull structure.Meanwhile,research results will provide reference for the revision of China's polar ship construction specifications.The main work and conclusions of this paper are as follows:1)Based on AH32 steel,the elongation,modulus of elasticity,yield strength and ultimate strength of this grade of steel at low and high temperatures were measured by means of tensile test and used for material properties in finite element numerical simulation.2)Using a similarity theory to scale the two different sizes of stiffened plates to obtain a test model.The stiffened plate samples were welded by Shielded Metal Arc Welding and Laser Beam Welding,and the influence of different welding methods on the initial defects of the stiffened plates was analyzed,and the compression test of the stiffened plates at different temperatures was carried out.The ultimate strength analysis of stiffened plates was carried out by finite element software ANSYS,and the influence of boundary conditions on the ultimate strength of stiffened plates was discussed.Set the initial defects of the stiffened plate in the finite element simulation according to the measured initial defect value and the empirical formula,and analyze the influence of the initial defect on the ultimate strength of the stiffened plate.3)Consider the coupling effect of adjacent stiffened plates.Select multiple multi-ribbed multi-span stiffened panel sizes for bulk carriers based on literature and specifications.The ultimate strength of these stiffened plates at different temperatures(-60 ° C,20 ° C,80 ° C)was calculated using the empirical formulas in the common specification and the finite element method.The effects of temperature on the ultimate strength and buckling behavior of stiffened plates under different buckling modes,as well as the effects of plate thickness,rib size,thermal stress and stiffened plate types on the ultimate strength and buckling behavior of stiffened plates at different temperatures were analyzed.4)Expand the research object to the hull structure,and compare and summarize the existing calculation methods and theories of the ultimate strength of the hull.The simplified algorithm and finite element simulation method are used to analyze the influence of temperature on the ultimate strength of the hull,which provides a reference for the structural strength assessment of polar ships.