Burst Pressure of Pipelines With Corrosion Anomalies Under High Longitudinal Strains

2018 ◽  
Author(s):  
Honggang Zhou ◽  
Yong-Yi Wang ◽  
Mark Stephens ◽  
Jason Bergman ◽  
Steve Nanney
Keyword(s):  
Numerical Analysis ◽  
Longitudinal Strain ◽  
Compressive Strain ◽  
Experimental Tests ◽  
Burst Pressure ◽  
General Corrosion ◽  
The Us ◽  
Full Scale Tests ◽  
The Impact ◽  
Longitudinal Strains

Existing corrosion assessment models were developed and validated under the assumption that internal pressure was the principal driver for burst failure and that longitudinal strain levels were low. The impact of moderate to high levels of longitudinal strain on burst capacity had not been explicitly considered. This paper summarizes work performed as part of a major effort funded by the US Department of Transportation Pipeline and Hazardous Materials Safety Administration (DOT PHMSA) aimed at examining the impact of longitudinal strain on the integrity of pipelines with corrosion anomalies. This paper focuses on the burst pressure of corroded pipes under high longitudinal strains. It is known that longitudinal tensile strain does not reduce the burst pressure relative to that of pipes subjected to low longitudinal strains. Therefore, existing burst pressure models can be considered adequate when the longitudinal strain is tensile. However, longitudinal compressive strain was found to lead to a moderate reduction in burst pressure. Numerical analyses were conducted to study the effect of longitudinal compressive strain on the burst pressure of corroded pipes. A burst pressure reduction formula was developed as a function of the longitudinal compressive strain. Full-scale tests were conducted to confirm the findings of the numerical analysis. Guidelines for assessing the burst pressure of corroded pipes under high longitudinal compressive strains were developed from the outcome of numerical analysis and experimental tests. The guidelines are applicable to different types of corrosion anomalies, including circumferential grooves, longitudinal grooves and general corrosion.

Tensile and Compressive Strain Capacity in the Presence of Corrosion Anomalies

2018 ◽  
Author(s):  
Honggang Zhou ◽  
Yong-Yi Wang ◽  
Mark Stephens ◽  
Jason Bergman ◽  
Steve Nanney
Keyword(s):  
Compressive Strain ◽  
General Corrosion ◽  
Department Of Transportation ◽  
Strain Capacity ◽  
Analytical Work ◽  
The Us ◽  
Different Types ◽  
Full Scale Tests ◽  
The Impact ◽  
Tensile Strain Capacity

Over the past 15 years, extensive studies have been conducted on the tensile strain capacity (TSC) and compressive strain capacity (CSC) of pipelines. The existing studies were mainly targeted at the design and construction of new pipelines. However, the impact of anomalies (e.g., corrosion anomalies) on the TSC and CSC has not been explicitly and adequately considered. This paper summarizes work performed as part of a major effort funded by the US Department of Transportation Pipeline and Hazardous Materials Safety Administration (DOT PHMSA) aimed at examining the impact of corrosion anomalies on the TSC and CSC of pipelines. In this work, the strain capacities were examined analytically, and the analytical work was compared to results from selected full-scale tests. Based on the summarized work, guidelines were developed for assessing the TSC and the CSC of corroded pipes. The guidelines are applicable to different types of corrosion anomalies, including circumferential grooves, longitudinal grooves and general corrosion. The strain capacities can be calculated using the key material properties and dimensions of pipe and corrosion anomalies as inputs.

Burst Pressure of Wrinkles Under High Longitudinal Strain

2018 ◽  
Author(s):  
Honggang Zhou ◽  
Yong-Yi Wang ◽  
Steve Nanney
Keyword(s):  
Longitudinal Strain ◽  
Biaxial Loading ◽  
Full Scale ◽  
Ground Movement ◽  
Burst Pressure ◽  
Current Assessment ◽  
Full Scale Tests ◽  
Assessment Procedures ◽  
The Impact ◽  
Longitudinal Strains

Wrinkles may form in pipelines experiencing high longitudinal strains in areas of ground movement and seismic activities. Current assessment procedures for wrinkles were developed and validated under the assumption that the predominant loading was internal pressure and that the level of longitudinal strain was low. The impact of wrinkles on the burst pressure of pipes under high longitudinal strain is not known. This paper describes work funded by US DOT PHMSA on the assessment of burst pressure of wrinkled pipes under high longitudinal strain. Both numerical analyses and full-scale tests were conducted to examine the burst pressure of wrinkled pipes. The numerical analysis results were compared with the full-scale test data. The effect of wrinkles on burst pressure were discussed. The biaxial loading conditions in the pipe were found affect the burst pressure of wrinkled pipes.

Assessment of Dents Under High Longitudinal Strain

2018 ◽  
Author(s):  
Bo Wang ◽  
Yong-Yi Wang ◽  
Brent Ayton ◽  
Mark Stephens ◽  
Steve Nanney
Keyword(s):  
Longitudinal Strain ◽  
Scale Validation ◽  
Compressive Strain ◽  
Full Scale ◽  
Ground Movement ◽  
Strain Capacity ◽  
Parametric Analyses ◽  
Full Scale Tests ◽  
Assessment Procedures ◽  
The Impact

Pipeline construction activities and in-service interference events can frequently result in dents on the pipe. The pipelines can also experience high longitudinal strain in areas of ground movement and seismic activity. Current assessment procedures for dents were developed and validated under the assumption that the predominant loading is internal pressure and that the level of longitudinal strain is low. The behavior of dents under high longitudinal strain is not known. This paper discusses work funded by US DOT PHMSA on the assessment of dents under high longitudinal strain. Parametric numerical analyses were conducted to identify and examine key parameters and mechanisms controlling the compressive strain capacity (CSC) of pipes with dents. Selected full-scale tests were also conducted to experimentally examine the impact of dents on CSC. The focus of this work was on CSC because tensile strain capacity is known not to be significantly affected by the presence of dents. Through the parametric analyses and full-scale validation tests, guidelines on the CSC assessment of dented pipes under high longitudinal strain were developed.

Tensile and Compressive Strain Capacity of Pipelines With Corrosion Anomalies

2016 ◽  
Author(s):  
Honggang Zhou ◽  
Ming Liu ◽  
Brent Ayton ◽  
Jason Bergman ◽  
Steve Nanney
Keyword(s):  
Numerical Analysis ◽  
Tensile Strain ◽  
Compressive Strain ◽  
General Corrosion ◽  
Test Results ◽  
Strain Capacity ◽  
Circumferential Groove ◽  
Compressive Buckling ◽  
Longitudinal Strains ◽  
Tensile Strain Capacity

Strain-based design and assessment (SBDA) methods have been developed to address integrity issues for pipelines subjected to ground movement hazards. The current practice of strain capacity assessment focuses on the tensile rupture of girth welds and compressive buckling of pipes. The integrity management of in-service pipelines often involves assessing pipe segments with anomalies, such as mechanical damage and corrosion. The existing strain capacity models do not yet include the impact of those anomalies. This paper covers a part of the outcome from a comprehensive research effort aimed at developing assessment procedures for pipelines containing corrosion anomalies and simultaneously subjected to large longitudinal strains. The resistance to tensile rupture and compressive buckling are the focus of the paper. Recommendations for the assessment of strain capacities were provided based on numerical analysis which identified key influencing parameters and controlling mechanisms. Full-scale experimental tests were also conducted to demonstrate the identified mechanisms and evaluate the assessment methods. Both numerical analysis and experimental test results demonstrate that: (1) corrosion anomalies can significantly reduce the tensile strain capacity (TSC) and compressive strain capacity (CSC) of pipes, (2) in addition to the depth and longitudinal length, the circumferential width of the corrosion anomalies has a significant impact on the TSC and CSC of pipes, (3) circumferential-groove corrosion anomalies reduce the tensile strain capacity more than general corrosion anomalies of the same depth and circumferential width, and (4) general corrosion anomalies reduce the compressive strain capacity more than the circumferential-groove anomalies of the same depth and circumferential width. The analysis and experimental test results shown in this paper can support development of SBDA procedures and guidelines of pipelines subjected to large longitudinal strains.

scholarly journals Influence of the Cyclic Hardening Model on the Results of the Numerical Analysis of Fatigue Life on Example of the Compressor Blade

2019 ◽  
Vol 26 (2) ◽  
pp. 7-14
Author(s):  
Arkadiusz Bednarz
Keyword(s):  
Numerical Analysis ◽  
Leading Edge ◽  
Experimental Tests ◽  
Cyclic Hardening ◽  
Load Cycle ◽  
Geometrical Model ◽  
Fatigue Tests ◽  
Compressor Blade ◽  
Hardening Model ◽  
The Impact

Abstract The main goal of the presented work is to determine the impact of the cyclic hardening model on the numerical results of the ε-N fatigue test. As an object of study, compressor blade (from PZL-10W helicopter engine) was used. The examined blade was made of EI-961 alloy. In numerical analysis, a geometrical model of the blade with a preliminary defect was created. Geometrical defect – V-notch was created on the leading edge. This defect was introduced in order to weaken the structure of the element and the possibility of observing the crack initiation process (in experimental tests). Material data to ε-N analysis, based on Manson-Coffin-Basquin equation, were estimated for Mitchell’s model. This model was built based on strength data provided by the steel producer. Based on three different models of cyclic hardening (Manson, Fatemi, and Xianxin), a number of load cycles were calculated. Load cycle during numerical analysis was represented as resonance bending with an amplitude of displacement equal to A = 1.8 mm. Obtained results were compared with experimental data. Additionally, the analytical model of ε-N fatigue (depending on the cyclic hardening) was prepared. All the work carried out has been summarized by a comprehensive comparative analysis of the results. Obtained results and dependencies can be used in the selection of an appropriate model of cyclic hardening in further fatigue tests of many aerospace elements.

Impact of Thoracic Endovascular Aortic Repair on Pulsatile Circumferential and Longitudinal Strain in Patients With Aneurysm

2017 ◽  
Vol 24 (2) ◽  
pp. 281-289 ◽  
Author(s):  
Foeke J. H. Nauta ◽  
Guido H. W. van Bogerijen ◽  
Chiara Trentin ◽  
Michele Conti ◽  
Ferdinando Auricchio ◽  
...  
Keyword(s):  
Longitudinal Strain ◽  
Celiac Trunk ◽  
Ascending Aorta ◽  
Thoracic Endovascular Aortic Repair ◽  
Endovascular Aortic Repair ◽  
Sinotubular Junction ◽  
Aortic Repair ◽  
Brachiocephalic Trunk ◽  
The Impact ◽  
Longitudinal Strains

Purpose: To quantify both pulsatile longitudinal and circumferential aortic strains before and after thoracic endovascular aortic repair (TEVAR), potentially clarifying TEVAR-related complications. Methods: This retrospective study assessed the impact of TEVAR on pulsatile aortic strains through custom developed software and cardiac-gated computed tomography imaging of 8 thoracic aneurysm patients (mean age 71.0±8.2 years; 6 men) performed before TEVAR and during follow-up (median 0.1 months, interquartile range 0.1–5.8). Lengths of the ascending aorta, the aortic arch, and the descending aorta were measured. Diameters and areas were computed at the sinotubular junction, brachiocephalic trunk, left subclavian artery, and the celiac trunk. Pulsatile longitudinal and circumferential strains were quantified as systolic increments of length and circumference divided by the corresponding diastolic values. Results: Average pulsatile longitudinal strain ranged from 1.4% to 7.1%, was highest in the arch (p<0.001), and increased after TEVAR by 77% in the arch (7.1%±2.5% vs 12.5%±5.1%, p=0.04) and by 69% in the ascending aorta (5.6±2.3% vs 9.4±4.4%, p=0.06). Average pulsatile circumferential strain ranged from 3.6% to 5.0% before TEVAR and did not differ significantly throughout the thoracic aorta; there was a nonsignificant increase after TEVAR at the unstented sinotubular junction (5.0%±1.4% vs 6.3%±1.0%, p=0.18), with a significant increase at the celiac trunk (3.6%±1.8% vs 6.2%±1.8%, p=0.02). Pulsatile circumferential strains within stented segments were deemed unreliable due to image artifacts. Conclusion: TEVAR was associated with an increase of pulsatile longitudinal strains (in the arch) and circumferential strains (at the celiac trunk) in unstented aortic segments. These observations suggest increased pulsatile wall stress after TEVAR in segments adjacent to the device, which may contribute to the understanding of stent-graft–related complications such as retrograde dissection, aneurysm formation, and rupture.

Systematic review methodology for development: An example from microfinance

2018 ◽  
Vol 43 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Carina Van Rooyen ◽  
Ruth Stewart ◽  
Thea De Wet
Keyword(s):  
Systematic Review ◽  
International Development ◽  
Health Sector ◽  
Evidence Based ◽  
Systematic Review Methodology ◽  
Development Interventions ◽  
The Us ◽  
Sub Saharan ◽  
The Impact ◽  
Evidence Based Decision Making

Big international development donors such as the UK’s Department for International Development and USAID have recently started using systematic review as a methodology to assess the effectiveness of various development interventions to help them decide what is the ‘best’ intervention to spend money on. Such an approach to evidence-based decision-making has long been practiced in the health sector in the US, UK, and elsewhere but it is relatively new in the development field. In this article we use the case of a systematic review of the impact of microfinance on the poor in sub-Saharan African to indicate how systematic review as a methodology can be used to assess the impact of specific development interventions.

The Impact of Monetary and Fiscal Policies on the Stock Market in the United States (U.S); Evidence from Linear ARDL Framework

2020 ◽  
Vol 11 (1) ◽  
pp. 132-132
Author(s):  
Aref Emamian
Keyword(s):  
United States ◽  
Stock Market ◽  
The United States ◽  
Real Effective Exchange Rate ◽  
Annual Data ◽  
Fiscal Policies ◽  
Long Run ◽  
The Us ◽  
Short Run ◽  
The Impact

This study examines the impact of monetary and fiscal policies on the stock market in the United States (US), were used. By employing the method of Autoregressive Distributed Lags (ARDL) developed by Pesaran et al. (2001). Annual data from the Federal Reserve, World Bank, and International Monetary Fund, from 1986 to 2017 pertaining to the American economy, the results show that both policies play a significant role in the stock market. We find a significant positive effect of real Gross Domestic Product and the interest rate on the US stock market in the long run and significant negative relationship effect of Consumer Price Index (CPI) and broad money on the US stock market both in the short run and long run. On the other hand, this study only could support the significant positive impact of tax revenue and significant negative impact of real effective exchange rate on the US stock market in the short run while in the long run are insignificant. Keywords: ARDL, monetary policy, fiscal policy, stock market, United States

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