Investigation On Ultimate Tensile Strength Of Offshore Platform Steel With Random Corrosion Pits

The offshore platform will be corroded inevitably in the service process. The corrosion behavior has a significant impact on the ultimate strength of the offshore platform. Its structural safety is necessary to the utilization of the marine resources, the protection of the marine environment and the protection of human life. Therefore the consequences of the platform structure's damage and failure will be unbearable. From the above, it is helpful to develop the platform structure design and reduce the accident loss by a reasonable assessment of the ultimate bearing capacity of the platform. Considering the random corrosion of the steel structure in the offshore platform, the Monte Carlo method and the stochastic finite element method are combined to study the ultimate tensile load of the randomly distributed corrosion plates.In this paper, the 981 offshore platform project is selected as the background and the WDH370 steel production is considered as the research object. The effect of pitting corrosion on the ultimate strength of offshore platform steel are analyzed. The main contents in this paper are listed as follows:1. The method of the parametric modeling and the collaborative computation is performed by MATLAB and ABAQUS, to achieve the goal for the automatic computation program including the finite element pretreatment, computation and process. Calculated by ABAQUS finite element software, the proposed method is verified in nonlinear simulation computation.2. The corrosion plate models with different corrosion rate and yield ratio are calculated. The data of ultimate load and elastic stiffness is extracted and analyzed to obtain the quantitative statistical relationship between corrosion rate, yield ratio and residual ultimate load ratio, elastic stiffness reduction respectively.3. A number of tensile tests of the standard specimens are carried out to obtain the ultimate tensile load. The specimen made by WDH370 steel were manufactured into plate with distributed corrosion pits on single or double side. By comparing numerical simulation experimental results, the relationship between corrosion rate and residual ultimate load ratio is verified.