Application of Tensile Strain Models to Multiple Grades of Pipelines

2014 ◽  
Author(s):  
Wenwei Zhang ◽  
Zhenyong Zhang ◽  
Jinyuan Zhang ◽  
Peng Yang
Keyword(s):  
Tensile Strain ◽  
Large Diameter ◽  
High Strength ◽  
Slope Movement ◽  
Experimental Database ◽  
Mine Subsidence ◽  
The Past ◽  
Discontinuous Permafrost ◽  
China National Petroleum Corporation ◽  
Tensile Strain Capacity

China National Petroleum Corporation (CNPC) has constructed large-diameter high-strength pipelines (X70 and X80) in the past decades in areas of seismic activities, mine subsidence, and slope movement using strain-based design (SBD) technology. More pipelines being constructed now traverse regions of active seismic activities, mine subsidence, slope movement, and discontinuous permafrost. CNPC is also interested in moving to linepipe grades higher than X80. In view of the recent development of various tensile strain models, work was undertaken to evaluate those models and determine the most appropriate models for current and future applications. In this paper, selected tensile strain models are reviewed and evaluated against an experimental database. The database of 80 tests from public-domain publications contains both full-scale pipe tests and curved wide plate tests with 46 tests from high strength pipes (X80 and above). The calculated tensile strain capacity from the selected models was compared with the test data. The models were evaluated and the applicability of the models to the linepipes of different strength levels was discussed.

Tensile Strain Capacity of X80 and X100 Welds

2012 ◽  
Author(s):  
Yong-Yi Wang ◽  
Fan Zhang ◽  
Ming Liu ◽  
Woo-Yeon Cho ◽  
Dong-Han Seo
Keyword(s):  
Tensile Strain ◽  
Large Diameter ◽  
High Strength ◽  
Experimental Tests ◽  
Mechanical Tests ◽  
Strain Capacity ◽  
Girth Welds ◽  
Energy Products ◽  
Tensile Strain Capacity ◽  
Potential Use

High-strength pipelines (API 5L grade X70 and above) provide viable economic options for large-diameter and high-pressure transmission of energy products. To facilitate the understanding and potential use of high-strength pipelines, the tensile strain capacity (TSC) of X80 and X100 girth welds was evaluated through a series of mechanical tests and analytical/computational modeling. The experimental tests include tensile, Charpy, SENT, and curved-wide-plate (CWP) tests. The TSC measured from CWP tests is compared with the prediction from TSC models developed at CRES. The TSC of the girth welds is assessed by comparing experimentally measured values with the expected TSC from similar welds. The assessment confirms that this particular set of X80 and X100 girth welds provide very good tensile strain capacity.

Enhancing Tensile Strain Capacity Through the Optimization of Weld Profiles

2014 ◽  
Author(s):  
Yong-Yi Wang ◽  
Yaoshan Chen ◽  
Mamdouh Salama
Keyword(s):  
Tensile Strain ◽  
High Strength Steels ◽  
High Strength ◽  
Recent Analysis ◽  
Strain Concentration ◽  
Strain Capacity ◽  
Weld Defects ◽  
Weld Region ◽  
Girth Welds ◽  
Tensile Strain Capacity

In order to optimize cost and performance of high pressure gas pipelines by reducing the wall thickness, pipeline companies are considering the use of higher grade (X70 or above) steels or a composite pipe of thin steel liner and fiber wrap. The use of high strength steels and thinner pipes can result in challenges when the pipe is installed in areas imposing high strain demand such as discontinuous permafrost regions. For high strength steels, the difficulty of ensuring the strength overmatching of the weld metal and the potential softening of the heat affected zone (HAZ) can result in gross strain concentration in the weld region and thus reduce the strain capacity of the pipeline in the presence of weld defects. Also, a thinner pipe has lower strain capacity than a thicker pipe for the weld defect of the same dimensions. One of the economical and effective ways of mitigating the possibility of gross strain concentration and increasing the strain capacity of a weld region containing weld defects is through the use of appropriate weld profiles. For instance, adding a smooth and wide layer of weld reinforcement (termed weld overbuild) can increase the effective strength of the weld. The effectiveness of the weld overbuild in improving the tensile strain capacity of girth welds is evaluated using the Level 4a approach of the PRCI-CRES tensile strain models. The crack-driving force is obtained through finite element analysis (FEA) of welds with planar weld and HAZ flaws of various sizes. It was demonstrated that weld overbuild with appropriate dimensions is an effective method to increase the tensile strain capacity (TSC) of girth welds which may have limited TSC without the overbuild. The role of weld profiles in girth weld integrity is discussed from the perspectives of historical evidence and more recent analysis and experimental tests.

scholarly journals Development of Ultra-Lightweight and High Strength Engineered Cementitious Composites

2021 ◽  
Vol 5 (4) ◽  
pp. 113
Author(s):  
Zhitao Chen ◽  
Junxia Li ◽  
En-Hua Yang
Keyword(s):  
Tensile Strain ◽  
High Strength ◽  
Matrix Composition ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites ◽  
Micromechanical Properties ◽  
Matrix Fracture ◽  
The Matrix ◽  
Lightweight Filler ◽  
Tensile Strain Capacity

In this study, ultra-lightweight and high strength Engineered Cementitious Composites (ULHS-ECCs) are developed via lightweight filler incorporation and matrix composition tailoring. The mechanical, physical, and micromechanical properties of the resulting ULHS-ECCs are investigated and discussed. ULHS-ECCs with a density below 1300 kg/m3, a compressive strength beyond 60 MPa, a tensile strain capacity above 1%, and a thermal conductivity below 0.5 w/mK are developed. The inclusion of lightweight fillers and the variation in proportioning of the ternary binder can lead to a change in micromechanical properties, including the matrix fracture toughness and the fiber/matrix interface properties. As a result, the tensile strain-hardening performance of the ULHS-ECCs can be altered.

A Case Study of Predicting Tensile Strain Capacity of In-Service Pipelines

2020 ◽  
Author(s):  
Junfang Lu ◽  
Ali Fathi ◽  
Nader Yoosef-Ghodsi ◽  
Debra Tetteh-Wayoe ◽  
Mike Hill
Keyword(s):  
Material Properties ◽  
Tensile Strain ◽  
Large Diameter ◽  
Ground Movement ◽  
Capacity Assessment ◽  
Pipe Material ◽  
Strain Capacity ◽  
Welding Processes ◽  
Tensile Strain Capacity

Abstract Strain-based design (SBD) method has evolved over the years for use in the construction of large-diameter, high pressure gas and liquid transmission pipelines. It has not been widely materialized for major construction projects because of the technical complexity which requires multidisciplinary expertise including, but not limited to, pipeline material properties, welding processes, mechanical testing, field construction, and weld inspection. The industry has been showing more interest in using this methodology for strain capacity assessment of in-service stress-based pipelines, especially those that are subjected to ground movement. The strain capacity assessment of the stress-based pipelines is essential to ensure structural integrity and operational safety of the pipeline. This has become more apparent due to recent incidents in pipeline industry caused by geotechnical hazards. This paper provides a case study of assessing the tensile strain capacity (TSC) of existing modern linepipes manufactured through thermomechanical controlled process (TMCP). The TSC was predicted using two main methodologies in the public domain: the CSA Z662-11 Annex C approach and the PRCI-CRES TSC model. Actual pipeline information and construction data are used to perform TSC assessment when possible. This includes pipe material properties, welding procedures qualified on the project pipe, and test weld properties. The predicted TSC and the estimated strain demand will allow for effective remediation decisions. This work helps to enhance pipeline strain management systems in response to the geotechnical and hydrotechnical issues and therefore fills the gaps in present day’s pipeline threat management programs in addition to crack, corrosion and mechanical damage threats. Through such a program, prevention, monitoring and mitigation strategies can be deployed to existing stress-based pipelines, especially in areas where pipeline strain is identified as a potential risk.

Multi-Tier Tensile Strain Models for Strain-Based Design: Part 2 — Development and Formulation of Tensile Strain Capacity Models

2012 ◽  
Author(s):  
Ming Liu ◽  
Yong-Yi Wang ◽  
Yaxin Song ◽  
David Horsley ◽  
Steve Nanney
Keyword(s):  
Driving Force ◽  
Tensile Strain ◽  
Weld Strength ◽  
Experiment Data ◽  
Pipe Wall Thickness ◽  
Crack Driving Force ◽  
Strain Capacity ◽  
Welding Processes ◽  
Tensile Strain Capacity

This is the second paper in a three-paper series related to the development of tensile strain models. The fundamental basis of the models [1] and evaluation of the models against experiment data [2] are presented in two companion papers. This paper presents the structure and formulation of the models. The philosophy and development of the multi-tier tensile strain models are described. The tensile strain models are applicable for linepipe grades from X65 to X100 and two welding processes, i.e., mechanized GMAW and FCAW/SMAW. The tensile strain capacity (TSC) is given as a function of key material properties and weld and flaw geometric parameters, including pipe wall thickness, girth weld high-low misalignment, pipe strain hardening (Y/T ratio), weld strength mismatch, girth weld flaw size, toughness, and internal pressure. Two essential parts of the tensile strain models are the crack driving force and material’s toughness. This paper covers principally the crack driving force. The significance and determination of material’s toughness are covered in the companion papers [1,2].

The Design, Development and Validation of an Innovative High Strength, Self Monitoring, Composite Pipe Liner for the Restoration of Energy Transmission Pipelines

2006 ◽  
Author(s):  
Kyle Bethel ◽  
Steven C. Catha ◽  
Melvin F. Kanninen ◽  
Randall B. Stonesifer ◽  
Ken Charbonneau ◽  
...  
Keyword(s):  
High Pressures ◽  
Large Diameter ◽  
Cylindrical Tube ◽  
High Strength ◽  
Design Development ◽  
Energy Transmission ◽  
Engineering Research ◽  
Wide Range ◽  
Transmission Pipelines

The research described in this paper centers on a composite of thermoplastic materials that can be inserted in a degraded steel pipe to completely restore its strength. Through the use of fabrics consisting of ultra high strength fibers that are co-helically wrapped over a thin walled thermoplastic cylindrical tube that serves as a core, arbitrarily high pressures can be achieved. This paper first outlines the design, manufacturing and installation procedures developed for this unique material to provide a context for the engineering research. Based on this outline, the technological basis that has been developed for assuring the strength and long term durability of this concept during its insertion, and in its very long term service as a liner in energy transmission pipelines, is presented in detail. The research that is described includes burst testing of the material in stand alone pipe form, load/elongation testing of ultra high strength fabrics, and linear and nonlinear elastic and viscoelastic analysis models. This body of work indicates that the concept is fundamentally feasible for restoring a wide range of large diameter natural gas and liquid transmission pipelines to be able to carry arbitrarily high pressures over very long lifetimes. It also indicates that liners can be safely installed in long lengths even in lines with severe bends in a continuous manner. With further research the concept has the potential for eliminating hydro testing and smart pigging during service, and could possibly be installed in some lines that are currently unpiggable.

High-strength nitrogen removal of opto-electronic industrial wastewater in membrane bioreactor - a pilot study

2003 ◽  
Vol 48 (1) ◽  
pp. 191-198 ◽  
Author(s):  
T.K. Chen ◽  
C.H. Ni ◽  
J.N. Chen ◽  
J. Lin
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Organic Nitrogen ◽  
Membrane Bioreactor ◽  
High Strength ◽  
Experimental Period ◽  
Ammonia Nitrogen ◽  
Nitrifying Bacteria ◽  
Biological Degradation ◽  
The Past

The membrane bioreactor (MBR) system has become more and more attractive in the field of wastewater treatment. It is particularly attractive in situations where long solids retention times are required, such as nitrifying bacteria, and physical retention critical to achieving more efficiency for biological degradation of pollutant. Although it is a new technology, the MBR process has been applied for industrial wastewater treatment for only the past decade. The opto-electronic industry, developed very fast over the past decade in the world, is high technology manufacturing. The treatment of the opto-electronic industrial wastewater containing a significant quantity of organic nitrogen compounds with a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N) is very difficult to meet the discharge limits. This research is mainly to discuss the treatment capacity of high-strength organic nitrogen wastewater, and to investigate the capabilities of the MBR process. A 5 m3/day capacity of MBR pilot plant consisted of anoxic, aerobic and membrane bioreactor was installed for evaluation. The operation was continued for 150 days. Over the whole experimental period, a satisfactory organic removal performance was achieved. The COD could be removed with an average of over 94.5%. For TOC and BOD5 items, the average removal efficiencies were 96.3 and 97.6%, respectively. The nitrification and denitrification was also successfully achieved. Furthermore, the effluent did not contain any suspended solids. Only a small concentration of ammonia nitrogen was found in the effluent. The stable effluent quality and satisfactory removal performance mentioned above were ensured by the efficient interception performance of the membrane device incorporated within the biological reactor. The MBR system shows promise as a means of treating very high organic nitrogen wastewater without dilution. The effluent of TKN, NOx-N and COD can fall below 20 mg/L, 30 mg/L and 50 mg/L.

Application of Plastic Region Bolt Tightening to Flange Joint Assembly: Behavior of Large Diameter Flange

2009 ◽  
Author(s):  
Shinobu Kaneda ◽  
Hirokazu Tsuji
Keyword(s):  
Internal Pressure ◽  
Large Diameter ◽  
Plastic Region ◽  
Load Factor ◽  
Past Study ◽  
Flange Joint ◽  
The Past ◽  
Sealing Performance ◽  
Assembly Behavior ◽  
Bolted Flange

In the past study the plastic region tightening has been applied to the bolted flange joint with smaller nominal diameter and its advantages have been demonstrated, however, behavior of the bolted flange joint with larger diameter is not investigated. Flange rotation of the bolted flange joint with large diameter increases when the internal pressure is applied. Gasket stress is not uniform and it may cause leak accident. So, it is necessary to investigate the behavior of the larger diameter flange. The present paper describes the behavior of bolted flange joint with large diameter under plastic region tightening. Firstly, API 20-inch flange joint tightened to the plastic region by bolt with a smaller diameter and superiority in the uniformity of the axial bolt force is demonstrated. And then the internal pressure is applied to the bolted flange joint and the behavior of the additional axial bolt force is demonstrated. The axial bolt force decreases with increasing the internal pressure, and the load factor is negative due to increasing of the flange rotation. However, the load factor of the bolted flange joint tightened to the plastic region by using the bolt with the smaller diameter approached zero. Using the bolts with smaller diameter is advantageous to the flange joint with the larger diamter, whose load factor is negative, to prevent the leakage. Additionally, the leak rate from the bolted flange joint is measured and the sufficient sealing performance is obtained.

Employing Visual Image Correlation for the Measurement of Compressive Strains for Arctic Onshore Pipelines

2013 ◽  
Author(s):  
Istemi F. Ozkan ◽  
Daryl J. Bandstra ◽  
Chris M. J. Timms ◽  
Arthur T. Zielinski
Keyword(s):  
Strain Gauge ◽  
Strain Distribution ◽  
Compressive Strain ◽  
Geometrical Nonlinearity ◽  
Large Diameter ◽  
Measurement Techniques ◽  
Visual Image ◽  
Image Correlation ◽  
The Arctic ◽  
Discontinuous Permafrost

The Arctic onshore environment contains regions of discontinuous permafrost, where pipes may be subject to displacement-controlled bending in addition to high hoop stresses due to the pressurized fluids being transported. Considering the displacement-controlled nature of the deformations, strain-based design methodologies have been developed for permafrost pipelines when they are subject to bending and tension, which limit the longitudinal compressive and tensile strains. The widely accepted methodology in the industry to obtain the compressive strain capacity of line pipes subject to bending is to conduct Finite Element Analysis, incorporating material and geometrical nonlinearity calibrated against benchmark full-scale tests (bend tests) [1,2]. During these tests, compressive strains can be measured by various methods. The seemingly obvious choice is to apply strain gauges along the compression face of the specimen with respect to bending (intrados). This method will provide reasonable results until the compressive strain pattern begins to vary due to the initiation of buckle formation, which typically occurs shortly after yield. In order to measure average compressive strain beyond yield and up to buckling, the method used by C-FER Technologies (C-FER) involves using rotation measurement devices (inclinometers) to calculate the strain change between the most compressive and tensile fibres of the specimen (intrados and extrados, respectively) with respect to the bending direction. This value is then subtracted from the tensile strain gauge readings as measured by the strain gauge(s) located on the extrados of the specimen. The average compressive strain values derived from the inclinometer and extrados strain gauge measurements are based on the assumption that the plane sections remain plane. Recently, five large diameter pipes were bend-tested at C-FER’s testing facility in Edmonton, Alberta. In addition to the compressive strain measurement method used by C-FER described above (C-FER method), a visual image correlation (VIC) camera system was used to survey the strain distribution on the compressive face of the specimens. This paper gives a brief description of the test setup and instrumentation of this test program. The VIC camera setup and measurement technique are described and the overall strain distribution on the bending intrados as measured by the VIC cameras is presented. Strain measured by the VIC system is compared with gauge measurements at local points as well as the average compressive strain behaviour of the specimens obtained through the C-FER method described above. The results show that the VIC system can be a candidate to replace the conventional measurement techniques employed for compressive strain limit testing in support of strain-based design of arctic pipelines.

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