Strain Capacity of X100 High-Strain Linepipe for Strain-Based Design Application

2008 ◽  
Author(s):  
Satoshi Igi ◽  
Joe Kondo ◽  
Nobuhisa Suzuki ◽  
Joe Zhou ◽  
Da-Ming Duan
Keyword(s):  
Tensile Strain ◽  
Large Scale ◽  
High Strain ◽  
Compressive Strain ◽  
Local Buckling ◽  
Ground Movement ◽  
Frozen Ground ◽  
Long Distance ◽  
Element Analysis ◽  
Strain Capacity

In recent years, several natural gas pipeline projects have been planned for permafrost regions. Pipelines laid in such areas are subjected to large plastic deformation as a result of ground movement due to repeated thawing and freezing of the frozen ground. Likewise, in pipeline design methods, research on application of strain-based design as an alternative to the conventional stress-based design method has begun. Much effort has been devoted to the application of strain-based design to high strength linepipe materials. In order to verify the applicability of high-strain X100 linepipe to long distance transmission, a large-scale X100 pipeline was constructed using linepipe with an OD of 42″ and wall thickness of 14.3mm. This paper presents the results of experiments and Finite Element Analysis (FEA) focusing on the strain capacity of high-strain X100 linepipes. The critical compressive strain of X100 high-strain linepipes is discussed based on the results of FEA taking into account geometric imperfections. The critical tensile strain for high-strain X100 pipelines is obtained based on a curved wide plate (CWP) tensile test using specimens taken from girth welded joints. Specifically, the effect of external coating treatment on the strain capacity of X100 high-strain linepipe is investigated. The strain capacity of the 42″ X100 pipeline is considered by comparing the tensile strain limit obtained from girth weld fracture and critical compressive strain which occurs in local buckling under pure bending deformation.

Compressive and Tensile Strain Capacities of 48” X80 Line Pipes

2012 ◽  
Author(s):  
Hisakazu Tajika ◽  
Satoshi Igi ◽  
Takahiro Sakimoto ◽  
Shigeru Endo ◽  
Seishi Tsuyama ◽  
...  
Keyword(s):  
Tensile Strain ◽  
High Strain ◽  
Uniform Elongation ◽  
Compressive Strain ◽  
Experimental Studies ◽  
Local Buckling ◽  
Base Material ◽  
Pipe Surface ◽  
Strain Capacity ◽  
Strain Limit

This paper presents the results of experimental studies focused on the strain capacity of X80 linepipe. A full-scale bending tests of X80 grade, 48″ high-strain linepipes pressurized to 60% SMYS were conducted to investigate the compressive strain limit and tensile strain limit. The tensile properties Y/T ratios and uniform elongation of the pipes had variety. Three of four pipes are high strain pipes and these Y/T ratios are intentionally low with manufacturing method. One of these high-strain pipe was girth welded in its longitudinal center to investigate the effect of girth weld to strain capacity. The other was set as a conventional pipe that have higher Y/T ratio to make comparative study. The compressive strain limit focused on the critical strain at the formation of local buckling on the compression side of bending. After pipe reaches its endurable maximum moment, one large developed wrinkle and some small wrinkles on the pipe surface during bending deformation were captured relatively well from observation and strain distribution measurement. The tensile strain limit is discussed from the viewpoint of competition of two fracture phenomena: ductile crack initiation/propagation from an artificial notch at the HAZ of the girth weld, and strain concentration and rupture in the base material at the tension (opposite) side of the local buckling position.

Effects of Girth Weld on the Local Buckling Response of Conventional Grade Pipelines

2009 ◽  
Author(s):  
John Barrett ◽  
Shawn Kenny ◽  
Ryan Phillips
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Local Buckling ◽  
Numerical Procedure ◽  
Bending Moment ◽  
Ground Movement ◽  
Design Parameters ◽  
Element Analysis ◽  
Strain Capacity ◽  
Pipeline Design

Pipeline structural integrity is a critical component of pipeline design in extreme environmental conditions. Severe loads may be an issue in pipeline design if differential ground movement is prevalent in the design region, e.g. ground faulting and permafrost heave and settlement. Iceberg or ice keel interaction and large seabed deformations interacting may also be a critical design integrity issue for offshore pipelines in ice environments. Numerical finite element modelling procedures have been developed to assess the bending moment and strain capacity of several pipelines over various typical pipeline parameters. This study looks at the effects of girth-weld imperfection on the bending response of welded pipelines. Limited guidance is provided by pipeline design standards, for example DNV OS-F101 and CSA Z662, as to how to account for girth weld effects on the local buckling response. This paper investigates girth weld effects across a range of practical design parameters. Calibration of the numerical analysis was performed using available data, from full-scale tests and finite element analysis, for girth welded pipes in order to obtain confidence in the numerical procedure. The significance of girth weld effects was to reduce the peak bending moment capacity by 10% whereas strain capacity was reduced by as much as 35% based on the degree of girth weld imperfection. Girth weld effects have been acknowledged in industry, however, further research and physical testing is required to fully understand the problem, as shown in this paper.

Production of Grade X80 High Strain Linepipes for Seismic Region Application

2010 ◽  
Author(s):  
Ryuji Muraoka ◽  
Joe Kondo ◽  
Lingkang Ji ◽  
Hongyuan Chen ◽  
Yaorong Feng ◽  
...  
Keyword(s):  
High Strain ◽  
Uniform Elongation ◽  
High Strength ◽  
Longitudinal Direction ◽  
Full Scale ◽  
Ground Movement ◽  
Long Distance ◽  
Seismic Region ◽  
Strain Capacity ◽  
Pipe Bending

In order to achieve safety and reliability of long-distance gas transmission pipeline installed in seismic region while obtaining economical benefit by reducing material and construction cost, it is essential to apply the high-strength linepipes with sufficient strain capacity against buckling and weld fracture by seismic ground movement. At the same time, it is quite important to develop appropriate material requirement for strain capacity depending on the pipe dimension and strain demand of the region where the pipeline is installed. Grade X80 heavy gauge linepipes with excellent deformability were mass produced by applying advanced plate manufacturing technologies. These linepipes exhibit low Y/T and high uniform elongation in the longitudinal direction even after pipe coating. Strain capacity of the pipe against bending deformation with internal pressure was verified by conducting full scale pipe bending testing. In this paper, production results of high strain X80 linepipes for the application in long-distance pipelines in seismic region and full scale pipe bending and hydraulic burst test results were introduced.

scholarly journals High Strain Survivability of Piezoceramics by Optimal Bonding Adhesive Design

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2554 ◽  
Author(s):  
Hu Sun ◽  
Yishou Wang ◽  
Xinlin Qing ◽  
Zhanjun Wu
Keyword(s):  
Finite Element Analysis ◽  
Health Monitoring ◽  
Tensile Strain ◽  
High Strain ◽  
Aerospace Industry ◽  
Element Analysis ◽  
Strain Transfer ◽  
Impact Monitoring ◽  
Novel Approach ◽  
Host Structure

As one of the most common transducers used in structural health monitoring (SHM), piezoceramic sensors can play an important role in both damage detection and impact monitoring. However, the low tensile strain survivability of piezoceramics resulting from the material nature significantly limits their application on SHM in the aerospace industry. This paper proposes a novel approach to greatly improve the strain survivability of piezoceramics by optimal design of the adhesive used to bond them to the host structure. Theoretical model for determining the strain transfer coefficient through bonded adhesive from the host structure to piezoceramic is first established. Finite element analysis is then utilized to study the parameters of adhesive, including thickness and shear modulus. Experiments are finally conducted to validate the proposed method, and results show the piezoceramic sensors still work well when they are bonded on the host structures with tensile strain up to 4000 με by using the optimal adhesive.

Design of the Full Scale Experiments for the Testing of the Tensile Strain Capacity of X52 Pipes With Girth Weld Flaws Under Internal Pressure and Tensile Displacement

2014 ◽  
Author(s):  
Celal Cakiroglu ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Millan Sen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Tensile Strain ◽  
Oil And Gas ◽  
Full Scale ◽  
Element Analysis ◽  
Simultaneous Application ◽  
Strain Capacity ◽  
Tensile Strain Capacity

Pipelines can be subjected to significant amounts of tensile forces due to geotechnical movements like slope instabilities and seismic activities as well as due to frost heave and thaw cycles in arctic regions. The tensile strain capacity εtcrit of pipelines is crucial in the prediction of rupture and loss of containment capability in these load cases. Currently the Oil and Gas Pipeline Systems code CSA Z662-11 0 contains equations for the prediction of εtcrit as a function of geometry and material properties of the pipeline. These equations resulted from extensive experimental and numerical studies carried out by Wang et al [2]–[6] using curved wide plate tests on pipes having grades X65 and higher. Verstraete et al 0 conducted curved wide plate tests at the University of Ghent which also resulted in tensile strain capacity prediction methods and girth weld flaw acceptability criteria. These criteria are included in the European Pipeline Research Group (EPRG) Tier 2 guidelines. Furthermore Verstrate et al 0 introduced a pressure correction factor of 0.5 in order to include the effect of internal pressure in the tensile strain capacity predictions in a conservative way. Further research by Wang et al with full scale pipes having an internal pressure factor of 0.72 also showed that εtcrit decreases in the presence of internal pressure [10]–[15]. In their work, Wang et al presented a clear methodology for the design of full scale experiments and numerical simulations to study the effect of internal pressure on the tensile strain capacity of pipes with girth weld flaws [10]–[15]. However, there has been limited testing to enable a precise understanding of the tensile strain capacity of pipes with grades less than X65 as a function of girth weld flaw sizes and the internal pressure. In this paper the experimental setup for the testing of grade X52 full scale specimens with 12″ diameter and ¼″ wall thickness is demonstrated. In the scope of this research 8 full scale specimens will be tested and the results will be used to formulate the tensile strain capacity of X52 pipes under internal pressure. The specimens are designed for the simultaneous application of displacement controlled tensile loading and the internal pressure. Finite element analysis is applied in the optimization process for the sizes of end plates and connection elements. Also the lengths of the full scale specimens are determined based on the results from finite element analysis. The appropriate lengths are chosen in such a way that between the location of the girth weld flaw and the end plates uniform strain zones could be obtained. The internal pressure in these experiments is ranging between pressure values causing 80% SMYS and 30% SMYS hoop stress. The end plates and connection elements of the specimens are designed in such a way that the tensile displacement load is applied with an eccentricity of 10% of the pipe diameter with the purpose of increasing the magnitude of tensile strains at the girth weld flaw location. The results of two full scale experiments of this research program are presented. The structural response from the experiments is compared to the finite element simulation. The remote strain values of the experiment are found to be higher than the εtcrit values predicted by the equations in 0.

Alternative Compressive Strain Capacity Performance Limits for Strain Based Design Applications

2016 ◽  
Author(s):  
Shawn Kenny ◽  
Robin Gordon ◽  
Greg Swank
Keyword(s):  
Structural Engineering ◽  
Negative Impact ◽  
Numerical Study ◽  
Compressive Strain ◽  
Elastic Stability ◽  
Ground Movement ◽  
Performance Limits ◽  
Strain Capacity ◽  
Industry Standards ◽  
Limiting Condition

Existing industry standards have established the compressive strain capacity of pipelines within an empirical basis. The compressive strain capacity is generally associated with the peak moment. This approach has evolved from elastic stability concepts used in structural engineering for unrestrained pipe segments subject to primary loading (i.e. force or load control) conditions. This limiting condition does not take advantage of the observed performance for buried pipelines, when subjected to displacement control events such as differential ground movement, where the pipe curvature can exceed the peak moment response without loss of pressure containment integrity. This inherent conservatism may have a negative impact on project economics or sanction where the compressive strain capacity, rather than tensile rupture limits, governs the strain based design methodology. For these conditions, alternative performance limits defining the pipe compressive strain capacity are required. A numerical study was conducted, using finite element methods, to examine possible alternative compressive strain criteria for use in strain-based design applications. The results from this study and the requirements to bring these concepts forward through integration with industry recommended practice are presented.

Influence of Geotechnical Loads on Local Buckling Behavior of Buried Pipelines

2008 ◽  
Author(s):  
Hiva Mahdavi ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Local Buckling ◽  
Small Diameter ◽  
Ground Movement ◽  
Combined Loading ◽  
Fe Model ◽  
Buried Pipelines ◽  
Limit States

Buried pipelines can be subjected to differential ground movement events. The ground displacement field imposes geotechnical loads on the buried pipeline and may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. The conventional engineering approach to define the mechanical performance of pipelines has been based on combined loading events for “in-air” conditions. This methodology is assumed to be overly conservative and ignores soil effects that imposes geotechnical loads and also provides restraint, on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. In this study a three-dimensional continuum finite element (FE) model, using the software package ABAQUS/Standard, was developed and calibrated based on large-scale tests on the local buckling of linepipe segments for in-air and buried conditions. The effects of geotechnical boundary conditions on pipeline deformation mechanism and load carrying capacity were examined for a single small diameter pipeline with average diameter to thickness ratio and deep buried condition. The calibrated model successfully reproduced the large-scale buried test results in terms of the local buckling location, pipeline carrying load capacity, soil deformation and soil failure mechanism.

Tensile Strain Capacity of X80 Pipeline Under Tensile Loading With Internal Pressure

2010 ◽  
Author(s):  
Satoshi Igi ◽  
Takahiro Sakimoto ◽  
Nobuhisa Suzuki ◽  
Ryuji Muraoka ◽  
Takekazu Arakawa
Keyword(s):  
Internal Pressure ◽  
Driving Force ◽  
Tensile Strain ◽  
Surface Defects ◽  
Axial Loading ◽  
Element Analysis ◽  
Crack Driving Force ◽  
Strain Capacity ◽  
High Internal Pressure ◽  
Tensile Strain Capacity

This paper presents the results of experimental and finite element analysis (FEA) studies focused on the tensile strain capacity of X80 pipelines under large axial loading with high internal pressure. Full-pipe tensile test of girth welded joint was performed using high-strain X80 linepipes. Curved wide plate (CWP) tests were also conducted to verify the strain capacity under a condition of no internal pressure. The influence of internal pressure was clearly observed in the strain capacity. Critical tensile strain is reduced drastically due to the increased crack driving force under high internal pressure. In addition, SENT tests with shallow notch specimens were conducted in order to obtain a tearing resistance curve for the simulated HAZ of X80 material. Crack driving force curves were obtained by a series of FEA, and the critical global strain of pressurized pipes was predicted to verify the strain capacity of X80 welded linepipes with surface defects. Predicted strain showed good agreement with the experimental results.

Integrity Assessment of Post-Peak-Moment Wrinkles

2016 ◽  
Author(s):  
Ming Liu ◽  
Yong-Yi Wang ◽  
Millan Sen ◽  
Peter Song
Keyword(s):  
Longitudinal Strain ◽  
Failure Modes ◽  
High Strain ◽  
Compressive Strain ◽  
Local Strain ◽  
Fatigue Loading ◽  
Ground Movement ◽  
Negative Consequences ◽  
Integrity Assessment ◽  
Nominal Strain

For a pipeline experiencing a ground movement event, high longitudinal strain can be developed in the pipe longitudinal direction. When prerequisite requirements are met, ASME B31.4 allows up to 2% (nominal) longitudinal strain in a pipe. However, such high strain may be beyond the compressive strain capacity (CSC) of the pipe which is defined as the compressive strain corresponding to the maximum bending moment. Furthermore, wrinkles are usually formed at such a high strain level. Excessive local strain can accumulate around the wrinkles when the nominal strain goes beyond the CSC which can lead to significant wrinkle growth or even tearing of the pipe wall. Therefore, integrity of the pipes containing post-peak-moment wrinkles need to be assessed in order to confirm that the 2% nominal strain permitted in the ASME codes can be safely tolerated. A number of failure modes are possible. Firstly, a pipe must be capable of tolerating the nominal strain up to 2% under static loading without leak or rupture. Secondly, if a buckle or wrinkle is formed in the initial event of ground movement and no leak or rupture occurs, the buckle or wrinkle can be subjected to fatigue loading during the continued operation of the pipeline. The pipe should have sufficient remaining life till the anomalies are discovered (through inline inspection, for example) and mitigated. The fatigue loading can come from fluctuations in operation pressure, temperature, and/or other sources. In this paper, the immediate and long-term integrity of selected pipelines were assessed. The work has demonstrated that for the selected pipelines: (1) all lines meet the prerequisite conditions outlined in ASME B31.4 for the nominal strain limit up to 2%; (2) all lines are capable of tolerating nominal longitudinal strain up to 2% without immediate negative consequences; (3) for the wrinkles corresponding to nominal strain up to 2%, the wrinkles are expected to have finite fatigue lives and intervention within 5 to 7 years should be sufficient to prevent fatigue failures; and (4) locating and mitigating wrinkles corresponding to nominal longitudinal strain greater than 2% after a ground movement event may be necessary to ensure the safety of the pipelines.

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