On the Influence of the Corrosion Defect Size in the Welding Bead, Heat-Affected Zone, and Base Metal in Pipeline Failure Pressure Estimation: A Finite Element Analysis Study

In this study, failure pressure prediction was conducted in a pipeline with localized corrosion in base metal (BM), heat-affected zone (HAZ), and welding bead (WB) by finite element (FE) analysis. In the gas pipeline industry, there are methods (B31G, RESTRENGH, Shell, DNV, PCORR, and Fitnet FFS) and authors' approaches (Choi and Cronin) to determine the failure pressure. However, one disadvantage of these methods is that their equations do not consider damage corrosion at the HAZ or WB. They consider corrosion only in the BM. The corrosion shape is rectangular with a radius at the edges. In this study, the corrosion defect depth (d) was varied. The corrosion defect length (L) and the corrosion defect width (W) were equal. A type of rectangular corrosion defect with a radius at the edges in the longitudinal and circumferential directions was proposed. True stress–strain curves for BM, HAZ, and WB of an API 5 L X52 were introduced in the FE program. The results show that the pressure decreases as d, L, and W increase. This is because the damage corrosion is more severe as it grows, which causes the failure pressure to decrease.

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Effects of depth in external and internal corrosion defects on failure pressure predictions of oil and gas pipelines using finite element models

Advances in Structural Engineering ◽

10.1177/1369433220924790 ◽

2020 ◽

Vol 23 (14) ◽

pp. 3128-3139

Author(s):

Selene Capula Colindres ◽

Gerardo Terán Méndez ◽

Julio Cesar Velázquez ◽

Roman Cabrera-Sierra ◽

Daniel Angeles-Herrera

Keyword(s):

Finite Element ◽

Oil And Gas ◽

Effective Area ◽

The Finite Element Method ◽

Internal Corrosion ◽

Failure Pressure ◽

Corrosion Defect ◽

Corrosion Defects ◽

Pipeline Failure ◽

First Time

This study presents, for the first time, the mechanical behavior of API 5L pipeline steels X42, X52, X60, X70, X80, and X100 with external and internal corrosion defects as well as a combination of both defects that has been named external–internal corrosion defects. The conventional methods to predict failure pressure in corroded pipes, such as B31G, RSTRENG-1, SHELL, DNV-99, PCORRC, and FITNET FFS, have also been discussed in this article. In addition, pipeline failure pressure has been estimated using the finite element method, considering that it is the best approach to calculate actual failure pressure. The external and internal corrosion defect investigated in this research manifests as a rectangular shape with spherical ends at the edges. When the external–internal corrosion defect appears, failure pressure data decrease dramatically because of severe damage. This is due to the decrease in the ligament (effective area) caused by the corrosion defect. To have a good estimation of the pipeline failure pressure with an external–internal corrosion defect, DNV-99 method can be used with acceptable certainty.

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Numeral Simulation Study on Pipeline Corrosion Defects under Different Sizes and Pressures Based on FEM

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.215-216.1154 ◽

2012 ◽

Vol 215-216 ◽

pp. 1154-1157

Author(s):

Han Wu Liu ◽

Rui Hua Dong ◽

Han Xun Lv

Keyword(s):

Magnetic Field ◽

Finite Element ◽

Electric Current ◽

Three Dimensional ◽

Element Model ◽

Defect Depth ◽

Element Analysis ◽

Corrosion Defect ◽

Corrosion Defects ◽

Pipeline Corrosion

Finite element analysis software ANSYS is used to establish a three-dimensional finite element model of the pipeline corrosion defects by applying the boundary conditions of square wave excitation to simulate the distributions of current and induced magnetic field in the pipeline under various defect volumes. The results of the study show: When there is no corrosion defect in the pipeline, the electric current in the pipeline is basically even distribution. The magnetic field is distributed for the symmetrical vortex shape from head to foot, and it has not obviously gather phenomenon. When there are some corrosion defects in the pipeline, the electric current forms partial symmetrical vortex shape in both sides of the corrosion defect, and it is obviously assembled in the defect place. The simulation results of the different size defects show that the maximum magnetic field strength and the maximum current value increase with the defect depth increasing, while the output voltage decreases with the defect depth increasing. For the analysis of the stress distributions of the pipeline corrosion defect with certain size under different pressures, it was found that the maximum stress is 596 MPa when the bearing limit work pressure of the pipeline is 7 MPa, which is smaller than the yield strength with ensuring the safely running of the pipelines with defects.

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Electrochemical Corrosion Finite Element Analysis and Burst Pressure Prediction of Externally Corroded Underground Gas Transmission Pipelines

Journal of Pressure Vessel Technology ◽

10.1115/1.4038224 ◽

2017 ◽

Vol 140 (1) ◽

Cited By ~ 1

Author(s):

Ibrahim M. Gadala ◽

Magd Abdel Wahab ◽

Akram Alfantazi

Keyword(s):

Finite Element ◽

Stress Analysis ◽

Reaction Kinetics ◽

Moving Boundary ◽

Electrochemical Corrosion ◽

Burst Pressure ◽

Element Analysis ◽

Corrosion Defect ◽

Nonlinear Stress ◽

Pipeline Wall

An integrative numerical simulation approach for pipeline integrity analysis is presented in this work, combining a corrosion model, which is the main focus of this paper, with a complementary structural nonlinear stress analysis, using the finite element method (FEM). Potential distributions in the trapped water existing beneath pipeline coating disbondments are modeled in conjunction with reaction kinetics on the corroding exposed steel surface using a moving boundary mesh. Temperature dependencies (25 °C and 50 °C) of reaction kinetics do not greatly affect final corrosion defect geometries after 3-yr simulation periods. Conversely, cathodic protection (CP) levels and pH dependencies within the near-neutral pH range (6.7–8.5) strongly govern depth profiles caused by corrosion, reaching a maximum of ∼3 mm into the pipeline wall. A 0.25 V amplification of CP potential combined with a 0.5 mm widening in disbondment opening size reduces defect penetration by almost 30%. Resulting corrosion defect geometries are used for stress examinations and burst pressure evaluations. Furthermore, nonlinear elastic–plastic stress analysis is carried out using shell elements in order to predict the burst pressure of corroded pipes. Corrosion is modeled by reducing the stiffness of a damaged element that has the dimensions of the defect. The predicted burst pressures are in good agreement with those obtained using an experimental-based formula.

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Failure Pressure Prediction of Cracks in Corrosion Defects Using XFEM

Volume 1: Pipeline and Facilities Integrity ◽

10.1115/ipc2020-9312 ◽

2020 ◽

Author(s):

Xinfang Zhang ◽

Allan Okodi ◽

Leichuan Tan ◽

Juliana Leung ◽

Samer Adeeb

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Extended Finite Element Method ◽

Crack Depth ◽

Average Error ◽

Extended Finite Element ◽

Defect Depth ◽

Failure Pressure ◽

Corrosion Defects ◽

Element Method

Abstract Coating and cathodic protection degradation can result in the generation of several types of flaws in pipelines. With the increasing number of aging pipelines, such defects can constitute serious concerns for pipeline integrity. When flaws are detected in pipelines, it is extremely important to have an accurate assessment of the associated failure pressure, which would inform the appropriate remediation decision of repairing or replacing the defected pipelines in a timely manner. Cracks-in-corrosion (CIC) represent a class of defect, for which there are no agreed upon method of assessment, with no existing analytical or numerical models to predict their failure pressures. This paper aims to create a set of validated numerical finite element analysis models that are suitable for accurately predicting the failure pressure of 3D cracks-in-corrosion defects using the eXtended Finite Element Method (XFEM) technique. The XFEM for this study was performed using the commercially available software package, ABAQUS Version 6.19. Five burst tests of API 5L X60 specimens with different defect depths (varying from 52% to 66%) that are available in the literature were used to calibrate the XFEM damage parameters (the maximum principal strain and the fracture energy). These parameters were varied until a reasonable match between the numerical results and the experimental measurements was achieved. Symmetry was used to reduce the computation time. A longitudinally oriented CIC defect was placed at the exterior of the pipe. The profile of the corroded area was assumed to be semi-elliptical. The pressure was monotonically increased in the XFEM model until the crack or damage reached the inner surface of the pipe. The results showed that the extended finite element predictions were in good agreement with the experimental data, with an average error of 5.87%, which was less conservative than the reported finite element method predictions with an average error of 17.4%. Six more CIC models with the same pipe dimension but different crack depths were constructed, in order to investigate the relationship between crack depth and the failure pressure. It was found that the failure pressure decreased with increasing crack depth; when the crack depth exceeded 75% of the total defect depth, the CIC defect could be treated as crack-only defects, since the failure pressure for the CIC model approaches that for the crack-only model for ratios of the crack depth to the total defect depth of 0.75 and 1. The versatility of several existing analytical methods (RSTRENG, LPC and CorLAS) in predicting the failure pressure was also discussed. For the corrosion-only defects, the LPC method predicted the closest failure pressure to that obtained using XFEM (3.5% difference). CorLAS method provided accurate results for crack-only defects with 7% difference. The extended finite element method (XFEM) was found to be very effective in predicting the failure pressure. In addition, compared to the traditional Finite Element Method (FEM) which requires extremely fine meshes and is impractical in modelling a moving crack, the XFEM is computationally efficient while providing accurate predictions.

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The Evaluation of Failure Pressure for Corrosion Defects Within Girth or Seam Weld in Transmission Pipelines

2004 International Pipeline Conference, Volumes 1, 2, and 3 ◽

10.1115/ipc2004-0216 ◽

2004 ◽

Cited By ~ 6

Author(s):

Young-pyo Kim ◽

Woo-sik Kim ◽

Young-kwang Lee ◽

Kyu-hwan Oh

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Limit Load ◽

The Body ◽

Element Analysis ◽

Burst Test ◽

Corrosion Defect ◽

Seam Weld ◽

Failure Assessment ◽

Corrosion Defects

The failure assessment for corroded pipeline has been considered with the burst test and the finite element analysis. The burst tests were conducted on 762mm diameter, 17.5mm wall thickness and API 5L X65 pipe that contained specially manufactured rectangular corrosion defect. The failure pressures for corroded pipeline have been measured by burst testing and classified with respect to corrosion sizes and corroded regions — the body, the girth weld and the seam weld of pipe. Finite element analysis was carried out to derive failure criteria of corrosion defect within the body, the girth weld and the seam weld of the pipe. A series of finite element analyses were performed to obtain a limit load solution for corrosion defects on the basis of burst test. As a result, the criteria for failure assessment of corrosion defect within the body, the girth weld and the seam weld of API 5L X65 gas pipeline were proposed.

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Finite Element Analysis and Research on Corrosion Defect of Tank Floor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.853.514 ◽

2016 ◽

Vol 853 ◽

pp. 514-518

Author(s):

Zhi Jun Yang ◽

De Shu Chen ◽

Liang Chen ◽

Yu Zhuo Liu ◽

Ran An ◽

...

Keyword(s):

Magnetic Field ◽

Finite Element ◽

Magnetic Flux ◽

Magnetic Flux Leakage ◽

Bottom Plate ◽

Element Analysis ◽

Corrosion Defect ◽

Leakage Magnetic Field ◽

Leakage Field ◽

Flux Leakage

Storage tank is an essential vessel in petrochemical industry, and the corrosion of tank is an important reason for the safety hazard. The corrosion of tank bottom plate is more serious than the tank wall, and it is not easy to check and repair, when damaged to a certain extent it will cause the leakage of the media, then lead to waste of energy, environmental pollution, at the same time it will cause a major accident. Magnetic flux leakage testing is widely used in the field of tank floor inspection with the advantages of fast scanning speed, accurate results and so on. In this paper, the finite element simulation and analysis of the corrosion defect leakage magnetic field is used to obtain the data, and the characteristic of the leakage magnetic field is extracted. The effect of defect depth and width and shape on the magnetic flux leakage field is studied, and the distribution curve of the magnetic flux leakage field is obtained.

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MODELING THE WORK OF THE HEAD OF A HYDROMECHANICAL EXPANDER FOR WELDED PIPES OF A LARGE DIAMETER

IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY ◽

10.35211/1990-5297-2020-4-239-35-42 ◽

2020 ◽

pp. 35-42

Author(s):

L. M. Gurevich ◽

V. F. Danenko ◽

A. A. Istrati ◽

V. A. Sonnova

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Internal Pressure ◽

Base Metal ◽

Heat Affected Zone ◽

Welded Joint ◽

Large Diameter ◽

Design Parameters ◽

Maximum Stresses ◽

Distribution Of Stresses

Finite element simulates of changing stresses and strains under loading by gradually increasing internal pressure of cylindrical welded vessels was carried out. The vessels had an annular mechanically inhomogeneous welded joint with different mechanical properties of the joint, heat-affected zone, and base metal. Maximum stresses developed in the caps of the vessels, and the annular joint are lightly loaded. The distribution of stresses and strains in joint at various design parameters of the vessels is investigated.

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A Review of Finite Element Analysis and Artificial Neural Networks as Failure Pressure Prediction Tools for Corroded Pipelines

Materials ◽

10.3390/ma14206135 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6135

Author(s):

Suria Devi Vijaya Kumar ◽

Michael Lo Yin Kai ◽

Thibankumar Arumugam ◽

Saravanan Karuppanan

Keyword(s):

Neural Networks ◽

Finite Element ◽

Artificial Neural Networks ◽

Structural Integrity ◽

The Finite Element Method ◽

Element Analysis ◽

Strength Assessment ◽

Failure Pressure ◽

Prediction Tools ◽

Artificial Neural

This paper discusses the capabilities of artificial neural networks (ANNs) when integrated with the finite element method (FEM) and utilized as prediction tools to predict the failure pressure of corroded pipelines. The use of conventional residual strength assessment methods has proven to produce predictions that are conservative, and this, in turn, costs companies by leading to premature maintenance and replacement. ANNs and FEM have proven to be strong failure pressure prediction tools, and they are being utilized to replace the time-consuming methods and conventional codes. FEM is widely used to evaluate the structural integrity of corroded pipelines, and the integration of ANNs into this process greatly reduces the time taken to obtain accurate results.

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