Residual Strength of High Grade Steel Oil and Gas Pipelines with Double Corrosion Defects
In order to strengthen the safety evaluation of high grade steel pipelines with double corrosion defects,based on the plastic failure criterion,the equivalent stress and residual strength at the defect were simulated by using Workbench finite element software,and the effects of many parameters,such as the length of the defect,the depth of the defect and the spacing of the defect,on the residual strength were investigated.The 99%interaction criterion was used to determine the ultimate action distance of double corrosion defects,the evalua-tion method of the residual strength of double corrosion defects was formed,and the data were verified.The results show that with the in-crease of internal pressure,the pipeline goes through elastic stage,yield stage and post-yield strengthening stage successively.When the de-fect depth is deep,the effect of axial spacing on the maximum equivalent stress is larger,but the effect of defect depth on the maximum equivalent stress is smaller.When n<2.5 and c<1.26,the interaction and influence between corrosion defects should be considered.The modified formula can be used to calculate the residual strength of high grade steel with double corrosion defects.The calculated result is clos-er to the experimental value than DNV-RP-F101 specification,and the maximum relative error is less than 1.74%.The research results can provide theoretical basis and practical reference for improving the level of pipeline integrity management.
NETL
NSTL
万方数据
维普
