Non-linear Finite Element Research For The Corrosion Defects Of Pipeline Residual Strength On Complex Loadings

As a major energy consumption country,the construction of our country is becoming more and more importance to oil and gas transportation pipeline.Long-distance underground pressure piping can produce varying degrees of corrosion.Underground pipeline with corrosion defects directly contact with the soil around the pipe body.It will be affected by complex loads.The paper consider the pressure piping of grade X80 steel as the research object,using the method of finite element analysis to study failure pressure of pipeline on the pure internal pressure,combined internal pressure and bending moment and combined internal pressure and axial force.as a function of the defect depth,length and width.The main research results are as follows:(1)In this paper,set up containing a three-dimensional nonlinear finite element model of pipeline with single corrosion defect,by comparing the actual corrosion pipe blasting experiment results and the literature results,to verify the accuracy of the finite element model.(2)The corrosion of pipeline on internal pressure,combined internal pressure and bending moment and combined internal pressure and axial force by the equivalent stress nephogram,the failure positions of pipeline corrosion defect are at the center of the corrosion defect.(3)The corrosion of pipeline under the action of internal pressure,combined internal pressure and bending moment and combined internal pressure and axial force,pipeline failure pressure decreases with the increment of the axial length of defect,and decreases more and more slowly.When pipeline is under the action of internal pressure,pipeline failure pressure tends to be a constant value large than 250 mm,but pipeline is under combined internal pressure and bending moment and combined internal pressure and axial force,pipeline failure pressure still decreases.