New evaluation method of failure pressure of steel pipeline with irregular-shaped defect

摘要

The relation between the failure pressure of pipeline with irregular-shaped defect and the characteristic geometric parameters is more complex than regular-shaped defect. Therefore, it is necessary to study the evaluation method of failure pressure of pipeline with irregular-shaped defect. This paper presents a case study on the failure pressure of irregular-shaped defect based on finite element model and experimental tests. The case is composed of shallow patch and deep defect included in the shallow patch. The effect of the length, depth and the longitudinal spacing of deep defects on the failure pressure of irregular-shaped defect are analyzed. Based on the limit longitudinal spacing between deep defects, the evaluation length of irregular-shaped defect is obtained. According to the irregularity of the depth profile of irregular-shaped defect, the axial projection shape of defect is equivalent to different regular shape. Combined with the effective depth of equivalent shape and the evaluation length, a new evaluation method for predicting failure pressure of steel pipeline with irregular-shaped defect is proposed, and the accuracy of the new method is verified by comparing with the experimental results for different steel grades.