Strength of Line Pipe With Dent and Crack Defect

2010 ◽  
Author(s):  
Abu Rafi ◽  
Jorge Silva ◽  
Sara Kenno ◽  
Sreekanta Das ◽  
Richard Kania ◽  
...  
Keyword(s):  
Test Data ◽  
Pipe Wall ◽  
Test Procedure ◽  
Line Pipe ◽  
Research Organizations ◽  
Pressure Tests ◽  
The University ◽  
Crack Defect ◽  
Pipe Lines

Pipeline industry and various research organizations have been undertaking studies to understand how the pressure strength of line pipes reduces as the defects in the line pipes grow. Defect in pipe lines can be in the form of corrosion, dent, wrinkle, gouge, crack, and combinations of these. A large number of studies have been completed in developing methods for determining the pressure strength of line pipes with dent and gouge defects and also in the form of combined dent-gouge defect. Some of these studies were undertaken with the intention of determining the pressure strength of line pipes when a combined dent and crack (dent-crack) defect has formed. However, in these studies no cracks were simulated in the test pipe specimens; instead, a gouge (machined cut or notch) was produced and considered as a crack. Therefore, it is not realistic to call this defect a dent-crack defect; rather, it should be called dent-gouge defect. Hence, the current project is being undertaken at the University of Windsor to study how the dent-crack defect influences the pressure strength of line pipes. In this study, a crack in true sense was introduced in the pipe wall. Two different techniques were used to simulate the crack in the pipe wall. This paper discusses the procedures used in this study to simulate crack and dent. In addition, the test procedure and test data obtained from denting and pressure tests are discussed.

Behavior of X60 Line Pipe Subjected to Axial and Lateral Deformations

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Navid Nazemi ◽  
Sreekanta Das
Keyword(s):  
Laboratory Tests ◽  
Structural Integrity ◽  
Pipe Wall ◽  
Lateral Load ◽  
Test Method ◽  
Line Pipe ◽  
Test Setup ◽  
Steel Pipes ◽  
Sustained Loads ◽  
The University

Buried pipelines may be subjected to various complicated combinations of forces and deformations. This may result in localized curvature, strains, and associated deformations in the pipe wall. As a result, wrinkle may form. The wrinkled pipeline may then develop a rupture in the pipe wall and lose its structural integrity if it is subjected to further sustained loads or deformations. Recently, laboratory tests on NPS6 steel pipes were undertaken at the University of Windsor to study the wrinkling and post-wrinkling behaviors of this NPS6 pipe when subjected to lateral load in addition to internal pressure and axial load. Four full-scale laboratory tests were conducted, and it was found that the application of lateral load on wrinkled pipe produces a wrinkle shape similar to that occurred in a field NPS10 line pipe. Complex test setup was designed and built for successful loading and completion of these tests. This paper makes a detailed discussion on the test setup, test method, loading and boundary conditions, instruments used, and test results obtained from this study.

Effect of Operating Pressure and Dent Depth on Burst Strength of NPS30 Linepipe With Dent–Crack Defect

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Hossein Ghaednia ◽  
Sreekanta Das ◽  
Rick Wang ◽  
Richard Kania
Keyword(s):  
Pipe Wall ◽  
Crack Depth ◽  
Test Procedure ◽  
Operating Pressure ◽  
Test Results ◽  
Burst Strength ◽  
Engineering Research ◽  
Line Pressure ◽  
Dent Depth ◽  
Crack Defect

Buried linepipe can be exposed to various external interferences and corrosive environment and as a result, damage in the form of dent or corrosion or crack or gouge or combination of any of these damages can form in the pipe wall. A defect combining dent and crack, often known as dent–crack defect, which may lead to a rupture or leak in the pipe wall and hence, the pipeline operator becomes concerned about the performance and safety of the pipeline. A research was recently completed at the Centre for Engineering Research in Pipelines (CERP), University of Windsor to study the influence of dent depth and operating line pressure on the pressure capacity (burst strength) of 30 in. diameter and X70 grade linepipe. This study found that the dent depth of 12% with crack depth of 4 mm or more can reduce the pressure capacity by 38%. This paper discusses the test specimens, test setup, test procedure, test results, and data obtained from finite element analyses.

Effect of Dent Depth on the Burst Pressure of NPS30 X70 Pipes With Dent-Crack Defect

2014 ◽  
Author(s):  
Hossein Ghaednia ◽  
Sreekanta Das ◽  
Rick Wang ◽  
Richard Kania
Keyword(s):  
Oil And Gas ◽  
Pipe Wall ◽  
Crack Depth ◽  
Test Procedure ◽  
Petroleum Products ◽  
Engineering Research ◽  
Line Pressure ◽  
Dent Depth ◽  
Crack Defect

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Buried linepipe can be exposed to various external interferences and corrosive environment and as a result, damage in the form of dent or corrosion or crack or gouge or combination of any of these damages can form in the pipe wall. Such damage or combined damages can reduce the pressure capacity of the pipeline. A defect combining dent and crack, often known as dent-crack defect, can develop in the wall of a buried oil and gas linepipe. This combined defect may lead to a leak or a rupture in the pipe wall and hence, the pipeline operator becomes concerned about the performance and safety of the pipeline when a dent-crack defect is detected in the field pipeline. A long-term research program is currently underway at the Centre for Engineering Research in Pipelines, University of Windsor to study the influence of various parameters such as dent depth and operating line pressure on the pressure capacity or burst strength of 30 inch diameter and X70 grade pipes with D/t of about 90. From the study completed so far, it has been found that the dent depth of 8% with crack depth of 4 mm or more can reduce the pressure capacity by 32%. This paper discusses the test specimens, test setup, test procedure, test results, and data obtained from finite element analyses.

Effects of Geometry, Temperature, and Test Procedure on Reported Failure Strains From Simulated Wide Plate Tests

2006 ◽  
Author(s):  
Yong-Yi Wang ◽  
Ming Liu ◽  
Yaoshan Chen ◽  
David Horsley
Keyword(s):  
Test Data ◽  
Failure Process ◽  
Test Procedure ◽  
Gage Length ◽  
Tensile Failure ◽  
Temperature Fields ◽  
Weld Strength ◽  
Width Ratio ◽  
Local Cooling ◽  
Linear Variable Displacement Transducer

Wide plate test is a valuable tool in the assessment of pipeline girth weld integrity. It has been used for welding procedure qualification and for the validation of theoretically based defect assessment procedures. Although the general form of the test has remained largely unchanged over the years, the size of the test specimen, strain measurement, and test procedure, has had some variations. The influence of these variables has not been adequately examined. While this might be acceptable for tests targeted for stress-based design in which a general pass/no-pass answer is desired, the requirements for data accuracy and consistency for strain-based design are much higher. Understanding the variability of the test data is critical for high strain applications. This paper examines the effects of test geometry, mainly the length to width ratio, on the reported failure strains, assuming material’s failure process remains the same. The influence of different strain measdurement procedures, such as the location and gage length of LVDTs (Linear Variable Displacement Transducer), is assessed for different materials and weld strength mismatch levels. The other consideration is the influence of temperature fields on the cold test data. The postulated cold tests use either local cooling at the location of the weld defect or uniform cooling. In the case of local cooling, the gage length of the LVDTs covers materials of different temperatures. Consequently the reported failure strains are affected by the distribution of the temperature fields. The effects of the temperature fields on the reported tensile failure strains are examined.

scholarly journals A comparison of friction modifier performance using two laboratory test scales

2018 ◽  
Vol 233 (2) ◽  
pp. 201-210 ◽  
Author(s):  
L Buckley-Johnstone ◽  
M Harmon ◽  
R Lewis ◽  
C Hardwick ◽  
R Stock
Keyword(s):  
Test Procedure ◽  
Full Scale ◽  
Data Sets ◽  
Test Machine ◽  
Performance Study ◽  
Friction Modifier ◽  
Additional Information ◽  
Large Spread ◽  
Dry Contact ◽  
The University

This paper describes two methods, carried out at two different test scales, for assessing the friction modifier performance. Study A used the wear data from a full-scale rig test at the voestalpine Schienen GmbH and compared it with the wear data from twin disc tests using the SUROS test machine at the University of Sheffield. Study B compared the ‘retentivity’ data, from a full-scale rig at the University of Sheffield, with the data from the SUROS tests. Study A concluded that a good correlation existed between the two scales although assumptions made in the full-scale contact calculation introduce a large spread into the results. There was a greater correlation between the two data sets at more severe contact conditions. Study B showed a different baseline coefficient of traction between the two scales and that a longer test length is required to fully evaluate the ‘retention’ of the friction modifier on the full-scale rig. The paper expands on a previous conference presentation on the same subject. Additional information on the test procedure and test rigs is included here. Surface and subsurface analyses of the SUROS test samples have also been added. The analyses have shown that applying the friction modifier leads to a similar wear mechanism as for the dry contact, but the wear is less severe and there is less subsurface deformation. A discussion describing the differences in test scales and comparing lab tests to field operation is also included.

Self-lubricated transport of bitumen froth

1999 ◽  
Vol 386 ◽  
pp. 127-148 ◽  
Author(s):  
DANIEL D. JOSEPH ◽  
RUNYAN BAI ◽  
CLARA MATA ◽  
KEN SURY ◽  
CHRIS GRANT
Keyword(s):  
Pressure Gradient ◽  
Oil Sands ◽  
Pipe Wall ◽  
Extraction Process ◽  
Hot Water ◽  
Turbulent Pipe Flow ◽  
University Of Minnesota ◽  
Lubricating Layer ◽  
Direct Measurements ◽  
The University

Bitumen froth is produced from the oil sands of Athabasca using the Clark's Hot Water Extraction process. When transported in a pipeline, water present in the froth is released in regions of high shear, namely at the pipe wall. This results in a lubricating layer of water that allows bitumen froth pumping at greatly reduced pressures and hence the potential for savings in pumping energy consumption. Experiments establishing the features of the self-lubrication phenomenon were carried out in a 25 mm diameter pipeloop at the University of Minnesota, and in a 0.6 m diameter pilot pipeline at Syncrude, Canada. The pressure gradient of lubricated flows in 25 mm, 50 mm and 0.6 m diameter pipes closely follow the empirical law of Blasius for turbulent pipe flow; the pressure gradient is proportional to the ratio of the 7/4th power of the velocity to the 5/4th power of the pipe diameter, but the constant of proportionality is about 10 to 20 times larger than that for water alone. We used Reichardt's model for turbulent Couette flow with a friction velocity based on the shear stress acting on the pipe wall due to the imposed pressure gradient to predict the effective thickness of the lubricating layer of water. The agreement with direct measurements is satisfactory. Mechanisms for self-lubrication are also considered.

Investigation of an on-line pipe wall defect monitoring sensor

2010 ◽  
Vol 33 (1-2) ◽  
pp. 639-647 ◽  
Author(s):  
Akihiro Tagawa ◽  
Kazunari Fujiki ◽  
Fumio Kojima
Keyword(s):  
Pipe Wall ◽  
Line Pipe ◽  
Wall Defect ◽  
On Line

Fatigue Life Assessment for NPS30 Steel Pipe

2012 ◽  
Author(s):  
Jorge Silva ◽  
Hossein Ghaednia ◽  
Sreekanta Das
Keyword(s):  
Fatigue Life ◽  
Test Data ◽  
Crack Depth ◽  
Research Work ◽  
Longitudinal Crack ◽  
Assessment Model ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Remaining Fatigue Life ◽  
Crack Defect

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Aging and corrosive environment may lead to formation of various defects such as crack, dent, gouge, and corrosion. The performance evaluation of field pipelines with crack defect is important. Accurate assessment of crack depth and remaining fatigue life of pipelines with crack defect is vital for pipeline’s structural integrity, inspection interval, management, and maintenance. An experimental based research work was completed at the University of Windsor for developing a semi-empirical model for estimating the remaining fatigue life of oil and gas pipes when a longitudinal crack defect has formed. A statistical approach in conjunction with fracture mechanics was used to develop this model. Statistical analysis was undertaken on CT specimen data to develop this fatigue life assessment model. Finite element method was used for determining the stress intensity factor. The fatigue life assessment model was then validated using full-scale fatigue test data obtained from 762 mm (30 inch) diameter X65 pipe. This paper discusses the test specimens and test data obtained from this study. Development and validation of the fatigue life assessment model is also presented in this paper.

Carnival Time: Russian Higher Education and Science in the Postmodern Era

2020 ◽  
Vol 12 (3-1) ◽  
pp. 77-94
Author(s):  
Petr Orekhovsky ◽  
◽  
Vladimir Razumov ◽  
Keyword(s):  
University Teaching ◽  
Intellectual Activity ◽  
Academic Communities ◽  
Society Of The Spectacle ◽  
Russian Higher Education ◽  
Scientific Institutions ◽  
Research Organizations ◽  
Science And Education ◽  
Important Sign ◽  
The University

Since the end of the twentieth Century to the present, society has been undergoing deep systemic changes, which are accompanied by crisis phenomena. But the crisis affects society as a whole and science and education, as its components, in different ways. What hopes of the society should be associated with science and education? Communities of intellectuals (universities) go through the following stages in their formation: classical, modern, postmodern. Postmodernism brings polycentrism, fragmentation, deconstruction, stylization, collage, modeling and simulacra, and serialization to universities and research organizations. If classical and modernist views on intellectuals and Universities assumed that their activities were aimed at producing new knowledge and a new person, the postmodern transformation significantly changed academic communities and their environment. In order to better understand the essence of what happened, the authors refer to the phenomenon of carnival in the interpretation of M. M. Bakhtin. The most important sign of carnival is that everything is not what it seems. According to the sophists of antiquity, intellectual activity becomes a paid service. Is it appropriate to say that in a modern University teaching becomes a form of spiritual prostitution? Yes, it is appropriate, provided that the carnival of what is happening in the Russian University of the XXI century is determined by the change of roles and priorities of teachers, students, and support staff. The intensity and specificity of the carnival in a particular University depends on the specifics of the decision about the purpose of the University: issuance (sale) of a state-issued diploma, production of knowledge and/or training of qualified specialists. A serious external factor that reduces the authority of teachers and scientists is strengthening of trends towards relatively autonomous development of technologies and technics, which is clearly expressed in the phenomenon of the “revolution of interfaces”. Society is also changing, becoming the “society of the spectacle”, where the development of science, theater and professional sports has more and more similar characteristics. The crisis in science and education has always been a feature of postmodernism, an existential problem of intellectuals, which leads many of them to leave the walls of universities and scientific institutions.

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