Crack initiation and propagation of defects adjacent to the X65 pipeline spiral weld under axial tensile force

Abstract

The pipeline structure is prone to fracture by the synergistic effect of external forces and defects, which may lead to disastrous consequences. Therefore, it is of great engineering significance to study the crack initiation and propagation of defected pipelines. In this study, a series of simulations and experiments based on the wide plate tensile test were carried out. The effects of the size and position parameters of the defects adjacent to the pipeline spiral weld on crack initiation and propagation were investigated. The simulation results show that the dimensions of a single defect affected the crack initiation and propagation. Besides, the experiment results show that the mutual influence on the crack initiation and propagation between two defects was related to the position and distance of the double-defect. Observations of the pipeline stress and strain revealed that compared with the centrosymmetric double-defect, the likelihood of the fracture of the pipeline with the axisymmetric double-defect increased when the distance between the two defects was the same.