Determination of Burst Pressure For Line Pipes with Long Blunt Defects

摘要

Burst pressure is the maximum load in a pipeline. Its accurate prediction is critical to the safety design, integrity assessment and operational management of the pipeline. This paper overviews the commonly-used corrosion assessment methods, including ASME B31G, Modified B31G, LPC and PCORRC criteria, and describes three theoretical solutions of burst pressure for defect-free pipes in terms of Tresca criterion, von Mises criterion and ZL criterion - a newly proposed average shear stress yield criterion and the associated flow rules. These three theoretical solutions are extended to those for corroded pipes with infinitely long corrosion defects. Followed this, an elastic-plastic finite element analysis is performed using the commercial software ABAQUS with an aim to demonstrate numerical determination of burst pressure corresponding to the Mises and ZL solutions. The corrosion assessment methods are then applied to evaluate the burst pressure for six corroded line pipes with real long corrosion defects. It is concluded that the ZL solution and the PCORRC criterion can determine reasonable and conservative predictions for corroded pipelines with very long corrosion defects.