On the failure pressure of pipelines containing wall reduction and isolated pit corrosion defects

Analysis of shape and location effects of closely spaced metal loss defects in pressurised pipes

“…The material is modelled as an isotropic elasto-plastic material and true stress-true strain data are employed within Abaqus. It is acknowledged that some anisotropic behaviour does exist in the pipes as a result of the manufacturing processes; however, considering that the isotropic behaviour has yielded accurate results in terms of predicting failure pressure as reported by many researchers in the past [8,11,15,16,[26][27][28], only an isotropic hardening rule is used in this work. The true stress-strain values are obtained from the engineering uniaxial stress-stress data using equations (1) and (2) which are only valid up to necking where the loading situation is no longer uniaxial throughout the gauge length [29]:…”

“…The majority of pipes in the oil and gas sectors are made of ductile steel and operate in such a way that failure would occur in a ductile manner unless toughness is compromised leading to fracture. The failure criteria used in this work follow the stress-based failure criterion which has been widely used and shown to predict the collapse pressure of corroded pipes with good accuracy by various researchers [8,11,13,16,[39][40][41][42].…”

“…Filho et. al [16] used a similar failure criterion as suggested by Adilson et. al [11] where the pipe is considered to have failed when any element reaches stresses equal to the material's true UTS value.…”

“…Fitness assessment of metal loss in pipes has been researched since the 1970's right up to the present time. In chronological order, a number of examples are given in references [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Although extensive historical pipeline burst data exist in the literature, these were done more than 40 years ago on single defects, and data presented are incomplete due to the fact that earlier defect assessment procedures required only limited information on the defect geometry (depth and length) and material properties (SMYS and UTS) [18].…”

Pipelines Reliability Analysis Under Corrosion Effect and Residual Stress

“…In [25], the authors worked on the corrosion phenomenon, though they have associated it with the erosion. The results were very encouraging, and the proposed model was in good agreement with the experimental data in addition, providing a forecast precision for pipelines with straight and contracted geometries.…”