Ultimate Axial Load Prediction Model for X65 Pipeline with Cracked Welding Joint Based on the Failure Assessment Diagram Method

Abstract

Crack defects in the girth welds of pipelines have become an important factor affecting the safe operation of in-service oil pipelines. Therefore, it is necessary to analyze the factors affecting the safe operation of pipelines and determine the ultimate load during pipeline operation. Based on the failure assessment diagram (FAD) method described in the BS 7910 standard, the key factors affecting the evaluation results of the suitability of X65 pipeline girth welds are analyzed, and the effects of crack size, pipe geometry, and material properties on the evaluation results are investigated. The results indicate that the crack depth is more crucial to the safe operation of the pipeline than the crack length. While the effect of wall thickness is not significant, the misalignment can seriously aggravate the stress concentration. In general, the higher the yield ratio and tensile strength of the pipe material, the more dangerous the condition at the weld. The ultimate axial load that a crack-containing girth weld can withstand under different combinations of the above factors was determined. Furthermore, a data driven model via the optimized support vector regression method for the ultimate axial load of the X65 pipe was developed for engineering application, and the comparison results between the FEM results and the predicted results proved its accuracy and reliability.

Performance inspection and defect cause analysis of girth weld of high steel grade pipeline

“…Long-distance oil and gas transportation pipelines and station and yard facilities pipelines are almost completed by the welding process. [1][2][3][4][5][6][7] The welding quality directly affects the service safety of pipeline and station and yard facilities along the line. A welding joint was found to have excessive defects in the inspection process of the pipeline.…”

Performance Test and Cause Analysis of Girth Weld with Defects

“…For the technical staff, in the daily process of large diameter long distance pipeline construction, they need to pay more attention to the process of the welding process. In the process of welding to promote defects or quality problems, corresponding technical researchers need to take timely remedial measures to remedy defects, to ensure that the daily use of large diameter long-distance pipeline safety performance will not be affected [1][2][3][4][5][6][7]. In order to be able to make the use of large diameter long distance pipelines play a more important role in the process, in order to ensure the use of large diameter long distance pipeline safety performance, technology researchers tried on large diameter long-distance pipeline daily use process, quality inspection and safety performance on a regular basis to check, large diameter long distance pipeline transportation quality can gain greater protection.…”