Crack propagation and burst pressure of longitudinally cracked pipelines using extended finite element method

Abstract

This paper presents an investigation of the potential of extended finite element method (XFEM) implemented in Abaqus standard software, with maximum principal strain and fracture energy as damage parameters for analysis of crack propagation and prediction of burst pressure in pipelines. Models of API 5L X60 pipe were calibrated first, using data from single edge notched tension test and then using burst pressures from 3 full scale tests. Both calibrations produced low fracture energy and marginally varied strains as XFEM damage parameters. The models were used to predict burst pressures of pipe specimens having varying sizes of longitudinal cracks that were rectangular in profile and located on the external surface of the pipes. Burst pressures were also predicted using analytical methods and the results compared with tests and XFEM predictions. All analytical methods accurately predicted burst pressures of specimens with shallow crack depth but were inaccurate for deeper cracks. XFEM predictions were satisfactory for all specimens. Although few cracks were analysed, the results show XFEM can be effective for analysis of crack propagation and prediction of burst pressure in pipelines, but investigation using more crack sizes, pipe grades and pipe geometries is recommended for a firm conclusion.