Evaluation on pressure bearing capacity of X70 pipeline with pure dent defect

In order to evaluate the ultimate pressure bearing capacity of high-grade steel pipeline with pure dent defect, finite element analysis was performed for the deformation of steel pipeline during the formation of dent and the hydraulic test. In addition, full-scale hydrostatic burst test and strain test were also conducted for the pipeline with pure dent defect. Based on the full-scale test results, the results of the finite element analysis were verified in terms of burst pressure, rebound behavior and strain of pipeline with pure dent defect. The results show that the finite element analysis results are consistent with the experimental results in both processes of dent formation and hydraulic test, with an error of less than 10%. It indicates that the simulation of the dented pipe is accurate. Besides, the burst pressure of the dented pipe with a depth of 15.9% D(D refers to the outer diameter of pipeline) is 38 MPa, which is higher than the calculated burst pressure, 31.2 MPa, of the non-defective steel pipe, indicating that the tested dent has no adverse effect on the pressure bearing capacity of pipeline. The research findings provide technical support to the theoretical analysis of high-grade steel pipeline with dent defect.