Burst Tests on Pipeline Containing Irregular Shaped Corrosion Defects

2008 ◽  
Author(s):  
Adilson C. Benjamin ◽  
Aldo R. Franzoi ◽  
Jose´ Luiz F. Freire ◽  
Ronaldo D. Vieira ◽  
Jorge L. C. Diniz
Keyword(s):  
Depth Profile ◽  
Effective Area ◽  
Metal Loss ◽  
Defect Depth ◽  
Corrosion Defect ◽  
Spark Erosion ◽  
X80 Steel ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Outside Diameter

A corrosion defect can be considered as being of a regular shape if its defect depth profile is relatively smooth and the longitudinal area of metal loss is approximately rectangular. A corrosion defect can be considered as being of an irregular shape if its defect depth profile presents one or more major peaks in depth. In this paper the burst tests of four tubular specimens are presented. In these tests the tubular specimens were loaded with internal pressure only. The specimens were cut from longitudinal welded tubes made of API 5L X80 steel with a nominal outside diameter of 457.2 mm (18 in) and a nominal wall thickness of 7.93 mm (0.312 in). Each of the four specimens had one external irregular shaped corrosion defect, machined using spark erosion. Measurements were carried out in order to determine the actual dimensions of each tubular specimen and its respective defect. Tensile specimens and impact test specimens were tested to determine material properties. The failure pressures measured in the laboratory tests are compared with those predicted by six assessments methods, namely: the ASME B31G method, the RSTRENG 085dL method, the DNV RP-F101 method for single defects, the RPA method, the RSTRENG Effective Area method and the DNV RP-F101 method for complex shaped defects.

Burst Tests on Pipeline Containing Interacting Corrosion Defects

2005 ◽  
Author(s):  
Adilson C. Benjamin ◽  
Jose Luiz F. Freire ◽  
Ronaldo D. Vieira ◽  
Jorge L. C. Diniz ◽  
Edmundo Q. de Andrade
Keyword(s):  
Material Properties ◽  
Laboratory Tests ◽  
Impact Test ◽  
Effective Area ◽  
Tubular Specimen ◽  
Spark Erosion ◽  
X80 Steel ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Outside Diameter

In this paper the burst tests of seven tubular specimens are presented. In these tests the tubular specimens were loaded with internal pressure only. The specimens were cut from longitudinal welded tubes made of API 5L X80 steel with a nominal outside diameter of 457.2 mm (18 in) and a nominal wall thickness of 7.93 mm (0.312 in). The specimen IDTS 1 is a defect-free pipe. The specimen IDTS 2 contains only one defect, herein called base defect. The base defect is an external flat bottomed defect with uniform width (circumferential dimension). The other five specimens contain groups of interacting defects constituted by the combination of two or more base defects. All the defects were machined using spark erosion. Measurements were carried out in order to determine the actual dimensions of each tubular specimen and its respective groups of defects. Tensile specimens and impact test specimens were tested to determine material properties. The failure pressures measured in the laboratory tests are compared with those predicted by six assessments methods, namely: the ASME B31G method, the RSTRENG 085dL method, the DNV RP-F101 method for single defects, the RPA method, the RSTRENG Effective Area method and the DNV RP-F101 method for interacting defects.

Burst Tests on Pipeline Containing Closely Spaced Corrosion Defects

2006 ◽  
Author(s):  
Adilson C. Benjamin ◽  
Jose Luiz F. Freire ◽  
Ronaldo D. Vieira ◽  
Edmundo Q. de Andrade
Keyword(s):  
Laboratory Tests ◽  
Impact Test ◽  
Effective Area ◽  
Tubular Specimen ◽  
Spark Erosion ◽  
Welded Tube ◽  
X80 Steel ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Outside Diameter

In this paper the burst tests of five tubular specimens are presented. In these tests the tubular specimens were loaded with internal pressure only. The specimens were cut from a longitudinal welded tube made of API 5L X80 steel with a nominal outside diameter of 457.2 mm (18 in) and a nominal wall thickness of 7.93 mm (0.312 in). The specimen IDTS 8 contains only one defect, herein called base defect. The base defect is an external flat bottomed defect with uniform width (circumferential dimension). The other four specimens contain groups of interacting defects constituted by the combination of three or more base defects. All the defects were machined using spark erosion. Measurements were carried out in order to determine the actual dimensions of each tubular specimen and its respective groups of defects. Tensile specimens and impact test specimens were tested to determine material properties. The failure pressures measured in the laboratory tests are compared with those predicted by five assessments methods, namely: the ASME B31G method, the RSTRENG 085dL method, the DNV RP-F101 method for single defects, the RPA method and the RSTRENG Effective Area method.

Burst Tests on Pipeline Containing Circumferential Corrosion Defects

2010 ◽  
Author(s):  
Adilson C. Benjamin ◽  
Jose´ Luiz F. Freire ◽  
Ronaldo D. Vieira ◽  
Jorge L. C. Diniz
Keyword(s):  
Internal Pressure ◽  
Material Properties ◽  
Impact Test ◽  
Tubular Specimen ◽  
Spark Erosion ◽  
X80 Steel ◽  
Corrosion Defects ◽  
Circumferential Defects ◽  
Tubular Specimens ◽  
Outside Diameter

Circumferential defects are the ones in which the width w is greater than the length L (w > L). In this paper the burst tests of three tubular specimens are presented. In these tests the tubular specimens were loaded with internal pressure only. The specimens were cut from longitudinal welded tubes made of API 5L X80 steel with a nominal outside diameter of 457.2 mm (18 in) and a nominal wall thickness of 7.93 mm (0.312 in). Each of the three specimens had one external circumferential corrosion defect, machined using spark erosion. Measurements were carried out in order to determine the actual dimensions of each tubular specimen and its respective defect. Tensile specimens and impact test specimens were tested to determine material properties. The failure pressures measured in the burst tests are compared with those predicted by five assessments methods, namely: the ASME B31G method, the RSTRENG 085dL method, the DNV RP-F101 method for single defects (Part B), the RPA method and the Kastner equation.

scholarly journals Burst Tests on Pipeline With Long External Corrosion

2000 ◽  
Author(s):  
Adilson C. Benjamin ◽  
Ronaldo D. Vieira ◽  
Jose Luiz F. Freire ◽  
Jaime T. P. de Castro
Keyword(s):  
Effective Area ◽  
Displacement Transducer ◽  
Strain Gages ◽  
Yield Strain ◽  
Pressure Transducers ◽  
Spark Erosion ◽  
Corrosion Defects ◽  
External Corrosion ◽  
Tubular Specimens ◽  
Outside Diameter

PETROBRAS is conducting a research project with the purpose of investigating the behavior of pipeline with long corrosion defects. In the first phase of this project, burst tests of 9 tubular specimens containing a single external simulated corrosion defect were carried out. These specimens were cut from longitudinal welded tubes made of API 5L X60 steel with an outside diameter of 323.9 mm and a wall thickness of 9.53 mm. All corrosion defects were smooth rectangular defects fabricated using spark erosion. Tensile specimens were tested to determine material properties. Each corroded specimen was instrumented with 10 post-yield strain gages rosettes, one displacement transducer and three pressure transducers. This paper describes the tubular specimens tested and the instrumentation used. The measured burst pressures are compared with those predicted by the ASME B31G, the RSTRENG 085dL, the RSTRENG Effective Area and the DNV RP-F101 (Part B) methods.

Burst Tests on Pipeline Containing Long Real Corrosion Defects

2004 ◽  
Author(s):  
Ricardo Dias de Souza ◽  
Adilson Carvalho Benjamin ◽  
Jose Luiz F. Freire ◽  
Ronaldo D. Vieira ◽  
Jorge L. C. Diniz
Keyword(s):  
Oil And Gas ◽  
Corrosion Damage ◽  
Effective Area ◽  
Assessment Methods ◽  
Corrosion Defect ◽  
Corrosion Defects ◽  
Level 1 ◽  
Tubular Specimens ◽  
Level 2 ◽  
Outside Diameter

Long defects are one of the various corrosion-damage geometries that may occur in oil and gas pipelines. Long internal defects appear in general at the bottom of the pipe, around 6 o’clock position, due to the presence of water at this place. Long external defects are caused in general by faults in the protective coating. The words “long defect” are being used herein to mean a corrosion defect longer than 20Det. In this paper the burst tests of five end-capped tubular specimens containing a single internal real corrosion defect are presented. In these tests the tubular specimens were loaded with internal pressure only. The specimens were cut from five longitudinal welded tubes made of API 5L X46 steel with an outside diameter of 457.2 mm and a wall thickness of 6.35 mm. The tubes are corroded pipe segments that were removed from service as part of a rehabilitation campaign. Each one of the five tubes contains a long and complex shaped internal defect. Measurements were carried out in order to determine the actual dimensions of each tubular specimen and its respective defect. Tensile specimens were tested to determine material properties. The failure pressures measured in the laboratory tests are compared with those predicted by two Level-2 assessment methods: the RSTRENG Effective Area method and the DNV RP-F101 method for complex shaped defects. Comparisons between the measured failure pressures and the failure pressures predicted by three Level-1 assessment methods (the ASME B31G method, the RSTRENG 085dL method and the DNV RP-F101 method for single defects) are also presented.

Burst Tests on Pipeline With Nonuniform Depth Corrosion Defects

2002 ◽  
Author(s):  
Adilson C. Benjamin ◽  
Jose Lui´z F. Freire ◽  
Ronaldo D. Vieira ◽  
Jaime T. P. de Castro
Keyword(s):  
Material Properties ◽  
Effective Area ◽  
Displacement Transducer ◽  
Strain Gages ◽  
Yield Strain ◽  
Pressure Transducers ◽  
Spark Erosion ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Outside Diameter

PETROBRAS is conducting a research project with the purpose of investigating the behavior of pipeline with long nonuniform corrosion defects. In the first phase of this project, burst tests of two tubular specimens were carried out. Each of the two specimens had one external nonuniform depth corrosion defect, machined using spark erosion. The specimens were cut from longitudinal welded tubes made of API 5L X60 steel with an outside diameter of 323.9 mm and a nominal wall thickness of 9.53 mm. Each of the two tubular specimens was instrumented with 17 post-yield strain gages rosettes, one displacement transducer and two pressure transducers. This paper describes the tubular specimens tested and the instrumentation used. The measured burst pressures are compared with those predicted by the ASME B31G and the RSTRENG Effective Area methods. The material properties used were determined by tests of tensile specimens. Photographs of the fractured defects are presented along with comments about their differences in shape. Some values of strain measured during the tests are also presented and commented.

Strain Analysis of Pipeline Test Specimens Containing Longitudinal and Circumferential Corrosion Defects

2011 ◽  
Vol 70 ◽  
pp. 422-427 ◽  
Author(s):  
José L. F. Freire ◽  
Adilson C. Benjamin ◽  
Ronaldo D. Vieira ◽  
Jorge L. C. Diniz
Keyword(s):  
Impact Test ◽  
Strain Analysis ◽  
Strain Gages ◽  
Spark Erosion ◽  
Pressure Tests ◽  
Strain Data ◽  
X80 Steel ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Outside Diameter

The elastic and plastic strain data of tubular specimens undergoing rupture under internal pressure tests are presented and analyzed. Six tubular specimens were tested. The specimens were cut from longitudinally welded tubes made of API 5L X80 steel with a nominal outside diameter of 457.2mm (18in) and a nominal wall thickness of 7.93mm (0.312in). Each of the six specimens had one external longitudinal or circumferential corrosion defect that had been machined using spark erosion. Tensile specimens and impact test specimens were tested to determine material properties. Post-yielding electrical resistance strain gages were used to measure the elastic and plastic strains. The failure pressures measured in the laboratory tests were compared with those predicted by the DNV RP-F101 method for single defects and by the Kastner equation. The paper also discusses the strength of the pipe segments used in the tests under the assumptions of following the Tresca rupture criterion.

Finite Element Modeling of the Failure Behavior of Pipelines Containing Interacting Corrosion Defects

2006 ◽  
Author(s):  
Edmundo Q. de Andrade ◽  
Adilson C. Benjamin ◽  
Paulo R. S. Machado ◽  
Leonardo C. Pereira ◽  
Breno P. Jacob ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Large Strains ◽  
Failure Behavior ◽  
Finite Element Models ◽  
Contour Plots ◽  
X80 Steel ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Outside Diameter

This paper describes the application of solid finite element models in the analysis of five tubular specimens containing interacting corrosion defects. Each of these specimens has been submitted to hydrotest up to failure as part of a previous research project. The specimens were cut from longitudinal welded tubes made of API 5L X80 steel with a nominal outside diameter of 457.2 mm (18 in) and a nominal wall thickness of 7.93 mm (0.312 in). The analyses accounted for large strains and displacements, stress-stiffening and material nonlinearity. The failure pressures predicted by the solid finite element models are compared with the failure pressures of these specimens measured in the laboratory burst tests carried out previously. Also the failure behavior of each specimen is described and illustrated by contour plots of stresses.

Assessment of Interacting Corrosion Defects in Thin-Walled Pipes

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Ahmed A. Soliman ◽  
Mohammad M. Megahed ◽  
Ch. A. Saleh ◽  
Mostafa Shazly
Keyword(s):  
Nonlinear Finite Element ◽  
Metal Loss ◽  
Test Results ◽  
Defect Depth ◽  
Element Analysis ◽  
Shell Elements ◽  
Codes Of Practice ◽  
Useful Life ◽  
Corrosion Defects ◽  
Interaction Rule

Abstract Corrosion in pipes is usually found in the form of closely spaced defects, which eventually reduce the pipe pressure carrying capacity and piping planned useful life. Codes and standards have been developed to evaluate the effect of such form of metal loss on the piping pressure carrying capacities. However, predictions of such codes are usually conservative, and hence, there is a need to assess their degree of conservatism. The present paper utilizes nonlinear finite element analysis (FEA) in estimating pressure carrying capacities of defective pipes, and hence provides an evaluation of codes degree of conservatism. Shell elements with reduced thickness at the corrosion defect are adopted and their accuracy is assessed by comparison with those of solid elements as well as experimental test results. The influence of defects interaction is investigated by considering two neighboring defects in an inclined direction to each other. The influence of inclination angle, inclined proximity distance between the two defects, and the defect depth to wall thickness ratio are investigated. Comparisons were made with predictions of codes of practice in all cases. Code predictions were found to be conservative compared to FEA results. Furthermore, the interaction rule embedded in the codes for checking for interaction leads to inaccurate predictions for closely spaced defects as it does not include the effect of defect depth.

Predicting the Failure Pressure of Pipelines Containing Nonuniform Depth Corrosion Defects Using the Finite Element Method

2003 ◽  
Author(s):  
Adilson Carvalho Benjamin ◽  
Edmundo Queiroz de Andrade
Keyword(s):  
Finite Element ◽  
Shell Model ◽  
Failure Behavior ◽  
Solid Model ◽  
Second Phase ◽  
The Finite Element Method ◽  
Spark Erosion ◽  
Corrosion Defects ◽  
Tubular Specimens ◽  
Deep Defects

PETROBRAS is conducting a research project with the purpose of investigating the behavior of pipelines containing long nonuniform depth corrosion defects. In the first phase of this project, burst tests of two tubular specimens were carried out. Each of the two specimens had one external nonuniform depth corrosion defect, machined using spark erosion. This defect consists of two short and deep defects within a long and shallow corrosion patch, longitudinally oriented. The second phase of the project aims at appraising the performance of two different finite element models: a shell model and a solid model. This paper describes the application of these models in the analysis of the two tubular specimens containing a long nonuniform depth defect that were tested in the first phase of this project. The failure pressures predicted by the two types of FE models are compared with the burst pressures measured in the laboratory tests. Also a comparison between the results obtained by these models is presented. It is concluded that the solid model is more accurate than the shell model, but both models proved to be capable of simulating the failure behavior of defects constituted by a long and shallow corrosion patch with deep defects over it.

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