Finite Element Analysis of Failure Pressure of X60 Pipeline with Double Defect

Extensive research on X80 pipeline steel has been conducted, while there is little research on X60 pipeline steel. In this study, FEM (Finite Element Method) on the double defect pipeline model of the outer and inner walls is conducted using ANSYS Workbench software. The research object is the X60 pipeline with rectangular double corrosion defect. Firstly, the stress distribution is examined; Secondly, by changing the geometric factors of the double defects on the outer and inner walls, the influence law on the failure pressure is examined; Finally, based on the FEM results, the failure pressure calculation formula for X60 pipeline with double corrosion defects on the outer and inner walls was fitted by MATLAB software, and whether the fitting formula was accurate and applicable was examined. The stress cloud map of double defect pipeline has two areas: The area near the defect and that far away from the defect, with the former belonging to the danger zone and the latter belonging to the safe zone, Specific to the double defect pipeline model with inner and outer walls, the failure pressure presents a sharp reduction as the defect depth elevates, and its impact on the failure pressure becomes increasingly significant with the narrowing axial distance between the two defects; the increasing defect length increases is related to decreasing failure pressure. In line with the significantly increased defect length, its impact on pipeline failure pressure gradually weakens; the width variation of double defect impacts pipeline failure pressure very slightly; The MATLAB fitting formula possesses a high fitting degree, and the FEM calculation data is basically distributed on the fitting curve, which can better fit the curve of the limit load variation law; The inner wall double defect model performs better in pressure ratio and error analysis. The conclusions drawn have specific reference significance for the safety assessment of oil and gas pipelines.