Behavior of wrinkled steel pipelines subjected to cyclic axial loadings

2007 ◽  
Vol 34 (5) ◽  
pp. 598-607 ◽  
Author(s):  
Sreekanta Das ◽  
J.J Roger Cheng ◽  
David W Murray
Keyword(s):  
Failure Strain ◽  
Axial Loading ◽  
Cyclic Strain ◽  
Full Scale ◽  
Axial Loads ◽  
Test Procedures ◽  
University Of Alberta ◽  
Ductile Behavior ◽  
Full Scale Tests ◽  
The University

Full-scale laboratory tests were carried out at the University of Alberta to investigate the post-wrinkling ultimate behavior of steel pipelines. The pipe specimens exhibited extreme ductile behavior and did not fail in fracture under monotonically increasing axisymmetric compressive axial loads and displacements. Fractures developed at the wrinkled region, however, when a wrinkled pipe specimen was subjected to cyclic strain reversals due to unloading and loading of primary loads. This paper presents test procedures, complete post-wrinkling behavior, fracture limit strain values, and fracture configurations obtained from full-scale tests on wrinkled pipe specimens under cyclic and monotonic axial loadings. Key words: steel pipeline, laboratory testing, cyclic axial loading, wrinkling, post-wrinkling behavior, accordion failure, strain reversals, fracture.

scholarly journals Laboratory Study of Local Buckling, Wrinkle Development, and Strains for NPS12 Linepipe

2000 ◽  
Author(s):  
Sreekanta Das ◽  
J. J. Roger Cheng ◽  
David W. Murray ◽  
S. A. Wilkie ◽  
Z. Joe Zhou
Keyword(s):  
Fluid Pressure ◽  
Local Buckling ◽  
Pipe Material ◽  
Axial Loads ◽  
Buried Pipelines ◽  
Test Procedures ◽  
Complex Load ◽  
University Of Alberta ◽  
Full Scale Tests ◽  
Internal Pressures

Buried pipelines are subjected to fluid pressure (oil/gas/water), axial loads, moments, and complex load combination histories. As a result, they may develop large compressive strains and curvatures leading to formation of localized buckles or wrinkles in the pipe shell. Recently, full-scale tests on 12.75″ diameter (NPS12) energy pipes have been carried out at the University of Alberta to study the behavior of wrinkle development and the ultimate limiting strains at the wrinkle locations. Different internal pressures, and axial loads were applied to produce a wrinkle, followed by load variations intended to produce fracture that could develop in buried pipelines in the field. Three different axially loaded tests are reported. Two different internal pressures were applied, namely, (i) 0.8py and (ii) 0.4py, where py is the required internal pressure to cause the yield stress of the pipe material to be developed in the circumferential direction. Also, two different specimen lengths were adopted. They are: (i) 406 mm (16 inch) and (ii) 736 mm (29 inch). All specimens were loaded axially until the wrinkle formed. It was observed that the pipes are highly ductile and very large compressive strains can be developed without fracture or leakage in the pipe wall. Because the pipe specimens of the first two tests did not fail (i.e. fracture) under monotonically increasing displacements and strains, the third wrinkled specimen was subjected to load histories involving strain reversals. This load history resulted in a low cycle failure after a very few cycles. The paper addresses test procedures, buckling and post-buckling behavior of NPS12 energy pipelines and relates them to three different types of strain measures, namely, material strain, wrinkle strain and overall strain as observed from these tests.

Steady State Techniques in Creep Force Estimation: Results From Full Scale Tests of the SOAC Vehicle on a Roller Rig

1989 ◽  
Vol 111 (1) ◽  
pp. 61-68
Author(s):  
Imtiaz-ul-Haque ◽  
E. Harry Law
Keyword(s):  
Steady State ◽  
Forced Response ◽  
Full Scale ◽  
Force Estimation ◽  
Test Procedures ◽  
Creep Force ◽  
Roller Rig ◽  
Full Scale Tests ◽  
The U.S

Steady state forced response tests of the SOAC vehicle were conducted on the roller rig (Roll Dynamics Unit) at the U.S. DOT/Transportation Test Center. This paper presents the test procedures, the results of the tests, and the analysis procedures developed for the estimation of the creep coefficients. Results of the estimates are compared with theory and possible reasons for discrepancies are discussed.

A New Rupture Prediction Model for Corroded Pipelines Under Combined Loadings

1998 ◽  
Author(s):  
Wei Wang ◽  
Marina Q. Smith ◽  
Carl H. Popelar ◽  
James A. Maple
Keyword(s):  
Prediction Model ◽  
Thermal Loading ◽  
Axial Loading ◽  
Full Scale ◽  
Element Analysis ◽  
Strain Limit ◽  
Rupture Pressure ◽  
Scale Test ◽  
Full Scale Tests

It is commonly believed that bending and other secondary loading will reduce the rupture pressure of a corroded pipe. This paper shows through theory, full-scale tests and finite element analysis (FEA) that this need not be the case in the field where displacement controlled bending and axial loading are induced by differential settlement and axial constraint. Based on this result, a new strain-based rupture prediction model is developed for buried corroded pipes subjected to internal pressure, lateral bending, thermal loading and residual stress. The selection of an appropriate “bulging factor,” the determination of a biaxial strain limit and the treatment of the heat affected zone (HAZ) are also discussed in the paper. The predicted rupture pressures agree well with the full-scale test results.

Full-Scale Tests of Cold Bend Pipes

2004 ◽  
Author(s):  
M. Sen ◽  
J. J. R. Cheng ◽  
D. W. Murray ◽  
J. Zhou ◽  
K. Adams ◽  
...  
Keyword(s):  
Compressive Strain ◽  
Local Buckling ◽  
Full Scale ◽  
Combined Loading ◽  
Experimental Program ◽  
Test Procedures ◽  
Buckling Behavior ◽  
Residual Strains ◽  
Full Scale Tests ◽  
Bend Angles

An experimental program sponsored jointly by SNAM Rete Gas, Tokyo Gas Co., Ltd. and TransCanada Pipelines Ltd. was conducted on cold bend pipes under combined loading. These tests were designed to study the local buckling behavior and to develop the critical compressive strain criteria for cold bend pipes under combined loading. The test program includes eight full-scale specimens of NPS24 and NPS30 pipes with pipe thickness up to 14.3 mm. The test parameters include different D/t ratios (44, 69, and 93), material grades (X60, X65, and X80), bend angles (1.0 to 1.5 degree/diameter), and operation pressures (0%, 40%, 60%, and 80% of SMYS). In addition to full-scale tests, initial imperfections and residual strains due to cold bend processes were also measured. This paper describes the test specimens, test setup, instrumentation, and test procedures used in the program. A brief discussion of the test results is also covered in the paper.

Centres for Health Evidence Demonstration Project

2013 ◽  
Author(s):  
Tracy Stewart ◽  
Denise Koufogiannakis ◽  
Robert S.A. Hayward ◽  
Ellen Crumley ◽  
Michael E. Moffatt
Keyword(s):  
Evidence Based Practice ◽  
Demonstration Project ◽  
Evidence Based ◽  
Research Opportunities ◽  
University Of Alberta ◽  
Information Usage ◽  
University Of Manitoba ◽  
The University ◽  
Hospital Wards ◽  
Support Evidence

This paper will report on the establishment of the Centres for Health Evidence (CHE) Demonstration Project in both Edmonton at the University of Alberta and in Winnipeg at the University of Manitoba. The CHE Project brings together a variety of partners to support evidence-based practice using Internet-based desktops on hospital wards. There is a discussion of the CHE's cultural and political experiences. An overview of the research opportunities emanating from the CHE Project is presented as well as some early observations about information usage.

scholarly journals Is the Letter ‘t’ in the Word ‘gourmet’? Disruption in Task-Evoked Connectivity Networks in Adults with Impaired Literacy Skills

NeuroSci ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 75-94
Author(s):  
Kulpreet Cheema ◽  
William E. Hodgetts ◽  
Jacqueline Cummine
Keyword(s):  
Developmental Disorders ◽  
Brain Networks ◽  
Literacy Skills ◽  
Resting State Networks ◽  
Skilled Readers ◽  
University Of Alberta ◽  
Domain Specific ◽  
Probe Task ◽  
The University ◽  
General Networks

Much work has been done to characterize domain-specific brain networks associated with reading, but very little work has been done with respect to spelling. Our aim was to characterize domain-specific spelling networks (SpNs) and domain-general resting state networks (RSNs) in adults with and without literacy impairments. Skilled and impaired adults were recruited from the University of Alberta. Participants completed three conditions of an in-scanner spelling task called a letter probe task (LPT). We found highly connected SpNs for both groups of individuals, albeit comparatively more connections for skilled (50) vs. impaired (43) readers. Notably, the SpNs did not correlate with spelling behaviour for either group. We also found relationships between SpNs and RSNs for both groups of individuals, this time with comparatively fewer connections for skilled (36) vs. impaired (53) readers. Finally, the RSNs did predict spelling performance in a limited manner for the skilled readers. These results advance our understanding of brain networks associated with spelling and add to the growing body of literature that describes the important and intricate connections between domain-specific networks and domain-general networks (i.e., resting states) in individuals with and without developmental disorders.

Investigation of planing craft maneuverability using full-scale tests

2021 ◽  
pp. 147509022110303
Author(s):  
Kazem Sadati ◽  
Hamid Zeraatgar ◽  
Aliasghar Moghaddas
Keyword(s):  
Full Scale ◽  
Performance Characteristics ◽  
Forward Speed ◽  
Speed Reduction ◽  
Planing Craft ◽  
Full Scale Tests ◽  
Turning Maneuver

Maneuverability of planing craft is a complicated hydrodynamic subject that needs more studies to comprehend its characteristics. Planing craft drivers follow a common practice for maneuver of the craft that is fundamentally different from ship’s standards. In situ full-scale tests are normally necessary to understand the maneuverability characteristics of planing craft. In this paper, a study has been conducted to illustrate maneuverability characteristics of planing craft by full-scale tests. Accelerating and turning maneuver tests are conducted on two cases at different forward speeds and rudder angles. In each test, dynamic trim, trajectory, speed, roll of the craft are recorded. The tests are performed in planing mode, semi-planing mode, and transition between planing mode to semi-planing mode to study the effects of the craft forward speed and consequently running attitude on the maneuverability. Analysis of the data reveals that the Steady Turning Diameter (STD) of the planing craft may be as large as 40 L, while it rarely goes beyond 5 L for ships. Results also show that a turning maneuver starting at planing mode might end in semi-planing mode. This transition can remarkably improve the performance characteristics of the planing craft’s maneuverability. Therefore, an alternative practice is proposed instead of the classic turning maneuver. In this practice, the craft traveling in the planing mode is transitioned to the semi-planing mode by forward speed reduction first, and then the turning maneuver is executed.

scholarly journals Access to Healthcare for Immigrant Children in Canada

2020 ◽  
Vol 17 (9) ◽  
pp. 3320
Author(s):  
Bukola Salami ◽  
Alleson Mason ◽  
Jordana Salma ◽  
Sophie Yohani ◽  
Maryam Amin ◽  
...  
Keyword(s):  
Health Outcomes ◽  
Service Providers ◽  
Social Determinant ◽  
Immigrant Children ◽  
Access To Healthcare ◽  
Cultural Barriers ◽  
Immigrant Parents ◽  
Financial Barriers ◽  
University Of Alberta ◽  
The University

Immigrants experience poorer health outcomes than nonimmigrants in Canada for several reasons. A central contributing factor to poor health outcomes for immigrants is access to healthcare. Previous research on access to healthcare for immigrants has largely focused on the experience of immigrant adults. The purpose of this study was to investigate how immigrants access health services for their children in Alberta, Canada. Our study involved a descriptive qualitative design. Upon receiving ethics approval from the University of Alberta Research Ethics Board, we invited immigrant parents to participate in this study. We interviewed 50 immigrant parents, including 17 fathers and 33 mothers. Interviews were audio recorded, transcribed, and analyzed according to the themes that emerged. Findings reveal that systemic barriers contributed to challenges in accessing healthcare for immigrant children. Participants identified several of these barriers—namely, system barriers, language and cultural barriers, relationship with health professionals, and financial barriers. These barriers can be addressed by policymakers and service providers by strengthening the diversity of the workforce, addressing income as a social determinant of health, and improving access to language interpretation services.

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