Ovalization Defect in Energy Pipes Caused by Concentrated Load

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Hossein Ghaednia ◽  
Sreekanta Das
Keyword(s):  
Structural Integrity ◽  
Complex Loading ◽  
Outer Wall ◽  
Buried Pipelines ◽  
Element Analysis ◽  
Cross Sectional ◽  
Concentrated Load ◽  
Engineering Research ◽  
Steel Pipes ◽  
The University

Steel pipes are used to build pipelines that carry gas and oil across a country or a continent. The majority of onshore pipelines run underground; hence, they are called buried pipelines. These buried pipelines must endure external interferences and complex loading that result from geotechnical causes, aggressive environments, and operational requirements. Many segments of an underground pipeline may rest on rock tips and other localized hard surfaces, resulting in concentrated reaction load acting on small area of the outer wall of the operating pipeline. As a result, permanent inward deformations in the pipe wall, known as dent defect, can form. In addition, a resulting cross-sectional irregularity, known as an ovalization defect, can also occur. Pipe ovalization defects are a concern of pipeline operating companies, as the defect may challenge a pipeline's operation and/or structural integrity and safety. This research was completed by the Centre of Engineering Research in Pipelines located at the University of Windsor to examine the effects that rock tip shape, operating (internal) pressure, and a pipe's diameter-to-thickness ratio (D/t) have on an NPS30 X70-grade pipe's ovalization defect when it is subjected to such a concentrated load. This article discusses the lab-based full-scale examinations, finite element analysis (FEA) simulations, results, and discussions.

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.

Fatigue Analysis on a Full Scale Fuselage Panel

2008 ◽  
Vol 385-387 ◽  
pp. 549-552 ◽  
Author(s):  
A. Apicella ◽  
Enrico Armentani ◽  
Stefano Priore
Keyword(s):  
Complex Loading ◽  
Constant Load ◽  
Butt Joint ◽  
Full Scale ◽  
Test Machine ◽  
Fatigue Load ◽  
Element Analysis ◽  
Longitudinal Joint ◽  
Joint Direction ◽  
The University

Fatigue test on a full scale panel with complex loading and geometry has been carried out using a tri-axial test machine specifically designed, built and located in the laboratory of the University of Naples. The aeronautical test panel was designed and manufactured by Alenia. The demonstrator is made up of two skins which are linked by a transversal butt-joint that is parallel to the stringer direction. A fatigue load was applied in the direction normal to the longitudinal joint, while a constant load was applied in the longitudinal joint direction. The demonstrator broke up after about 177000 cycles. Subsequently, a finite element analysis was carried out in order to correlate failure events; due to the biaxial nature of the fatigue loads, Sines criterion was used. The analysis was performed taking into account the different materials of which the panel is composed. The output shows good correlation between experimental data and numerical results, predicting the location on the panel exactly where the failure occurred.

Structural Integrity of Buckled Steel Pipes

2015 ◽  
Author(s):  
Aglaia E. Pournara ◽  
Theocharis Papatheocharis ◽  
Spyros A. Karamanos ◽  
Philip C. Perdikaris
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Structural Integrity ◽  
Local Strain ◽  
Element Analysis ◽  
Steel Pipeline ◽  
Steel Pipes ◽  
The Finite Element Analysis ◽  
Loading Case ◽  
Pipeline Wall

Local distortions on steel pipeline wall in the form of buckles may constitute a threat for the structural integrity of the steel pipeline. In the present paper, experimental research supported by numerical simulation is reported to investigate the structural integrity of buckled steel pipes. A series of six (6) full-scale experiments has been carried out on 6-inch X52 pipes, followed by finite element simulations. The buckled steel pipes are subjected to cyclic loading (bending or pressure) in order to estimate their residual strength and remaining fatigue life. The finite element analysis simulates the experimental procedure for each type of deformation and loading case, in order to estimate the local strain distributions at the buckled region. Based on the numerical results, fatigue life is predicted and compared with the experimental results using an appropriate defined damage factor. The results of the present study are aimed at evaluating existing guidelines and methodologies towards appropriate assessment of local wall distortions in steel pipelines.

Out-of-Roundness in NPS30 X70 Pipes Subjected to Concentrated Lateral Load

2014 ◽  
Author(s):  
Hossein Ghaednia ◽  
Jamshid Zohrehheydariha ◽  
Sreekanta Das ◽  
Rick Wang ◽  
Richard Kania
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Impact Load ◽  
Test Procedure ◽  
Research Work ◽  
Mechanical Damage ◽  
Lateral Load ◽  
External Pressure ◽  
Concentrated Load ◽  
Engineering Research

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Structural integrity of oil and gas transmission pipelines is often threatened by external interferences such as concentrated load, impact load, and external pressure. These external interferences can cause ‘mechanical damage’ leading to structural failure in onshore and offshore linepipes. Lateral load is applied as a concentrated load on a small area of pipe segment and can cause local buckling, bend, dent, or out-of-roundness in the pipe. As an example, a concentrated load in buried onshore linepipe can occur if a segment of the linepipe rests on a narrow rock tip or even a narrow hard surface. Such concentrated lateral load may or may not cause immediate rupture or leak in the linepipe; however, it may produce out-of-roundness with or without a dent in the pipe cross section, which can be detrimental to the structural and/or operational integrity of the pipeline. Hence, the pipeline operator becomes concerned about the performance and safety of the linepipe if a pipe section is subject to a sustained concentrated load. A research work using full-scale tests and finite element method (FEM) was undertaken at the Centre for Engineering Research in Pipelines (CERP), University of Windsor to study the influence of various internal pressures and diameter-to-thickness ratios on the out-of-roundness of 30 in diameter (NPS 30) and X70 grade pipes with D/t of 90 when subjected to a stroke-controlled concentrated load. This paper discusses the test specimens, test setup, test procedure, test results, and FEM results obtained from this study.

Structural Integrity of Steel Hydrocarbon Pipelines With Local Wall Distortions

2014 ◽  
Author(s):  
Aglaia E. Pournara ◽  
Spyros A. Karamanos ◽  
Theocharis Papatheocharis ◽  
Philip C. Perdikaris
Keyword(s):  
Fatigue Life ◽  
Structural Integrity ◽  
Local Stress ◽  
Element Analysis ◽  
Experimental Procedure ◽  
Steel Pipes ◽  
The Finite Element Analysis ◽  
Loading Case ◽  
Pipeline Wall ◽  
Local Distortions

Local distortions on pipeline wall in the form of dents or buckles may constitute a threat for the structural integrity of the steel pipeline. In the present paper, experimental research supported by numerical simulation is reported to investigate the structural integrity of smoothly dented steel pipes. A series of six (6) full-scale experiments on 6-inch X52 pipes has been carried out, and numerical simulations have also been conducted. The dented steel pipes are subjected to cyclic loading (bending or pressure) in order to estimate their residual strength and remaining fatigue life. The finite element analysis simulate the experimental procedure for each type of deformation and loading case, in order to estimate the local stress and strain distributions at the dented region. Based on the numerical results, fatigue life is predicted and compared with the experimental results. The results of the present study are aimed at evaluating existing guidelines and methodologies towards appropriate assessment of local wall distortions in steel pipelines.

Behavior of NPS30 Pipe Subject to Denting Load

2014 ◽  
Author(s):  
Hossein Ghaednia ◽  
Kyle Gerard ◽  
Sudip Bhattacharjee ◽  
Sreekanta Das
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Petroleum Products ◽  
Lateral Loads ◽  
Element Analysis ◽  
Engineering Research ◽  
Three Dimensional Finite Element

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Structural integrity of oil and gas transmission pipelines is often threatened by external interferences such as concentrated lateral loads and as a result, a failure of the pipeline may occur due to “mechanical damages”. Sometime, this load may not cause immediate rupture of pipes; rather form a dent which can reduce the pressure capacity of the pipeline. A dent is a localized defect in the pipe wall in the form of a permanent inward plastic deformation. This kind of defect is a matter of serious concern for the pipeline operator since a rupture or a leak may occur. Accordingly, an extensive experimental study is currently underway at the Centre for Engineering Research in Pipelines (CERP), University of Windsor on 30 inch (762 mm) diameter and X70 grade pipes with D/t of 90. The aim of this research is to examine the influence of various parameters such as dent shape and service pressure on strain distributions of dented pipe. Also, three-dimensional finite element models were developed and validated for determining strains underneath the indenter. The load-deformation behavior of pipes subject to this type of lateral denting load obtained from experimental study and finite element analysis is discussed in this paper. In addition, distributions of important strains in and around the dent obtained from the study are also discussed.

Measuring Critical Strains in Dent Defect of Oil and Gas Pipes

2016 ◽  
Author(s):  
Jandark Oshana-Jajo ◽  
Jamshid Zohrehheydariha ◽  
Hossein Ghaednia ◽  
Sreekanta Das
Keyword(s):  
Laboratory Testing ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Economic Loss ◽  
Physical Contact ◽  
Environmental Damage ◽  
Element Analysis ◽  
Engineering Research ◽  
Critical Strains ◽  
Pipe Materials

Steel pipelines are exposed to harsh environmental, geotechnical and other conditions and hence, they can be damaged. The damage can threaten the structural integrity of the pipeline and can cause economic loss and environmental damage if a failure occurs. A common way for pipelines to be damaged is through physical contact, creating a structural imperfection, dent, wrinkle, crack, and/or other damages or defects. A dent disrupts the pipeline’s circularity causing increased strains in concentrated areas. A research program was established and carried out to study the strain concentration of dented pipes. The study was completed using full-scale laboratory testing and numerical analysis at the Centre for Engineering Research in Pipelines (CERP). This study included four lab tests on two different pipe materials (X70 and X56) and finite element analysis (FEA) based parametric study.

Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems

1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Energy ◽  
Structural Integrity ◽  
Experimental Temperature ◽  
Temperature Profiles ◽  
Element Analysis ◽  
Drum Brake ◽  
Fea Model

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.

What Determines The Migration Intentions Of University Students?

2014 ◽  
Vol 1 (1) ◽  
pp. 193-198
Author(s):  
Heiko Haase ◽  
Arndt Lautenschläger
Keyword(s):  
University Students ◽  
Career Choice ◽  
Cross Sectional Study ◽  
Demographic Characteristics ◽  
Migration Decision ◽  
Considerable Proportion ◽  
Sectional Study ◽  
Intention To Stay ◽  
Cross Sectional ◽  
The University

AbstractThe paper aims at exploring determinants of the university students' intentions to stay within their university region. At this, we presume that students' career choice motivations are related to their professional intentions, which again, along with demographic characteristics, affect their migration decision. Our analysis is based on a cross-sectional study of 2,353 students from three different higher education institutions, two of them located in Germany and one in Namibia. Results indicate that in Germany migration matters because a considerable proportion of students intend to leave the university region after graduation. At this, we found that the students' geographical provenance exerts the most significant effect on the intention to stay. Moreover, certain professional intentions were directly and some career choice motivations were indirectly linked with the intention to remain at the university location. We present several conclusions and implications.

Factors Influencing Academic Stress on Students of University of Economics and Business - Vietnam National University

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Nham Phong Tuan ◽  
Nguyen Ngoc Quy ◽  
Nguyen Thi Thanh Huyen ◽  
Hong Tra My ◽  
Tran Nhu Phu
Keyword(s):  
Academic Stress ◽  
Stress Factors ◽  
Negative Effects ◽  
Cross Sectional ◽  
Stress Scale ◽  
Perceptions And Attitudes ◽  
National University ◽  
Questionnaire Surveys ◽  
The University ◽  
The Impact

The objective of this study is to investigate the impact of seven factors causing academic stress on students of University of Economics and Business - Vietnam National University: Lack of leisure time, Academic performance, Fear of failure, Academic overload, Finances, Competition between students, Relationships with university faculty. Based on the results of a practical survey of 185 students who are attending any courses at the University of Economics and Business - Vietnam National University, the study assesses the impact of stress factors on students. The thesis focuses on clarifying the concept of "stress" and the stress level of students, while pointing out its negative effects on students. This study includes two cross-sectional questionnaire surveys. The first survey uses a set of 16 questions to assess students’ perceptions and attitudes based on an instrument to measure academic stress - Educational Stress Scale for Adolescents (ESSA). The second survey aims to test internal consistency, the robustness of the previously established 7-factor structure. Henceforth, the model was brought back and used qualitatively, combined with Cronbach’s Alpha measurement test and EFA discovery factor analysis. This study was conducted from October 2019 to December 2019. From these practical analyzes, several proposals were made for the society, the school and the students themselves.

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