Strain Capacity and Deformation Behavior of HFW Linepipe

2016 ◽  
Author(s):  
Satoshi Igi ◽  
Satoru Yabumoto ◽  
Teruki Sadasue ◽  
Hisakazu Tajika ◽  
Kenji Oi
Keyword(s):  
Internal Pressure ◽  
Seismic Design ◽  
Full Scale ◽  
Bending Test ◽  
Uniaxial Compression Test ◽  
Design Code ◽  
Strain Capacity ◽  
Seismic Design Code ◽  
Full Scale Tests ◽  
Tensile Strain Capacity

Newly-developed high quality high frequency electric resistance welded (HFW) linepipes have recently been applied to offshore pipelines by using the reel-lay method and onshore in extremely low temperature environments because of their excellent low temperature weld toughness and cost effectiveness. In order to clarify the applicability of these HFW linepipes to seismic regions, a series of full-scale tests such as the bending test with internal pressure and the uniaxial compression test were conducted according to the seismic design code of the Japan Gas Association (JGA). Based on these full-scale tests, the safety performance of high quality HFW linepipe when applied to seismic regions is discussed in comparison with the mechanical properties obtained in small-scale tests, such as the tensile and compression properties of the base material and weld seam, focusing especially on the compressive and tensile strain capacity of HFW linepipes from the viewpoints of full-scale performance and geometrical imperfections. The results of the bending test under internal pressure and the uniaxial compression test without internal pressure complied with the JGA seismic design code for permanent ground deformation induced by lateral spreading and surface faults. In addition, a full-pipe tension test was also conducted in order to investigate the tensile strain capacity of HFW linepipes for axial deformation.

Deformation Capacity of Weld Seam of the High Quality HFW Linepipe

2015 ◽  
Author(s):  
Satoshi Igi ◽  
Satoru Yabumoto ◽  
Teruki Sadasue ◽  
Hisakazu Tajika ◽  
Kenji Oi
Keyword(s):  
Low Temperature ◽  
Internal Pressure ◽  
Seismic Design ◽  
Weld Seam ◽  
Full Scale ◽  
Bending Test ◽  
Design Code ◽  
High Quality ◽  
Seismic Design Code ◽  
Full Scale Tests

Newly-developed high quality high frequency electric resistance welded (HFW) linepipes have recently been used in pipelines in reel-lay applications and low temperature service environments because of their excellent low temperature weld toughness and cost effectiveness. In order to clarify the applicability of these HFW linepipes to the seismic environment, a series of full-scale tests such as bending test with internal pressure and uniaxial compression test were conducted according to the seismic design code in Japan gas association (JGA). Based on the above-mentioned full-scale tests, the safety performance of high quality HFW linepipe to apply to the seismic region is discussed in comparison with the mechanical properties in the small-scale tests such as the tensile and compression property of the base material and weld seam, especially focused on the strain capacity of HFW linepipe from the view points of full-scale performance and geometrical imperfection. Test results of the bending test with internal pressure and the uniaxial compression were complied with the JGA seismic design code for the permanent ground deformation induced by lateral spreading and surface faults.

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.

Tensile Strain Capacity Equations for Strain-Based Design of Welded Pipelines

2010 ◽  
Author(s):  
Sandeep Kibey ◽  
Xiangyu Wang ◽  
Karel Minnaar ◽  
Mario L. Macia ◽  
Doug P. Fairchild ◽  
...  
Keyword(s):  
Tensile Strain ◽  
Large Scale ◽  
Active Regions ◽  
Full Scale ◽  
Dimensional Parameter ◽  
Strain Capacity ◽  
Design Qualification ◽  
Full Scale Tests ◽  
Pipe Geometry ◽  
Tensile Strain Capacity

Various industry efforts are underway to improve or develop new methods to address the design of pipelines in harsh arctic or seismically active regions. Reliable characterization of tensile strain capacity of welded pipelines is a key issue in development of strain-based design methodologies. Recently, improved FEA-based approaches for prediction of tensile strain capacity have been developed. However, these FEA-based approaches require complex, computationally intensive modeling and analyses. Parametric studies can provide an approach towards developing practical, efficient methods for strain capacity prediction. This paper presents closed-form, simplified strain capacity equations developed through a large-scale 3D FEA-based parametric study for welded pipelines. A non-dimensional parameter is presented to relate the influence of flaw and pipe geometry parameters to tensile strain capacity. The required input parameters, their limits of applicability and simplified equations for tensile strain capacity are presented. The equations are validated through a comprehensive full-scale test program to measure the strain capacity of pressurized pipelines spanning a range of pipe grades, thickness, weld overmatch and misalignment levels. It is shown that the current simplified equations can be used for appropriate specification of weld and pipe materials properties, design concept selection and the design of full-scale tests for strain-based design qualification. The equations can also provide the basis for codified strain-based design engineering critical assessment procedures for welded pipelines.

Girth Weld Strength Matching Effect on Tensile Strain Capacity of Grade X70 High Strain Line Pipe

2018 ◽  
Author(s):  
Hisakazu Tajika ◽  
Takahiro Sakimoto ◽  
Tsunehisa Handa ◽  
Rinsei Ikeda ◽  
Joe Kondo
Keyword(s):  
High Strain ◽  
Limit State ◽  
Full Scale ◽  
Bending Test ◽  
High Grade ◽  
Line Pipe ◽  
Bending Tests ◽  
Strain Capacity ◽  
Pipeline Project ◽  
Pipe Bending

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipes with size of 36″ OD and 23mm WT was investigated with two types of experiments, which are full scale pipe bending tests and curved wide plate tests. The length of the specimen of full scale bending tests were approximately 8m and girth weld was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. Test pipes were cut and welded, GTAW in first two layer and then finished by GMAW. In one pipe, YS-TS over-matching girth weld (OVM) joint was prepared considering the pipe body grade. For the other pipe, intentionally under-matching girth weld (UDM) joint was prepared. After the girth welding, elliptical EDM notch were installed in the GW HAZ as simulated weld defect. In both pipe bending tests, the buckling occurred in the pipe body at approximately 300mm apart from the GW and after that, deformation concentrated to buckling wrinkle. Test pipe breaking locations were different in the two tests. In OVM, tensile rupture occurred in pipe body on the backside of buckling wrinkle. In UDM, tensile rupture occurred from notch in the HAZ. In CWP test, breaking location was the HAZ notch. There were significant differences in CTOD growth in HAZ notch in these tests.

Evaluation of the Effect of Internal Pressure and Flaw Size on the Tensile Strain Capacity of X42 Vintage Pipeline Using Damage Plasticity Model in Extended Finite Element Method (XFEM)

2019 ◽  
Author(s):  
Sylvester Agbo ◽  
Meng Lin ◽  
Iman Ameli ◽  
Ali Imanpour ◽  
Da-Ming Duan ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Tensile Strain ◽  
Extended Finite Element Method ◽  
Full Scale ◽  
Flaw Size ◽  
Test Results ◽  
Extended Finite Element ◽  
Tensile Strain Capacity

Abstract Pipelines subjected to displacement-controlled loading such as ground movement may experience significant longitudinal strain. This can potentially impact pipeline structural capacity and their leak-tight integrity. Reliable calibration of the tensile strain capacity (TSC) of pipelines plays a critical role in strain-based design (SBD) methods. Recent studies were focused mostly on high toughness modern pipelines, while limited research was performed on lower-grade vintage pipelines. However, a significant percentage of energy resources in North America is still being transported in vintage pipelines. Eight full-scale pressurized four-point bending tests were previously conducted on X42, NPS 22 vintage pipes with 12.7 mm wall thickness to investigate the effect of internal pressure and flaw size on TSC. The pipes were subjected to 80% and 30% specified minimum yield strength (SMYS) internal pressures with different girth weld flaw sizes machined at the girth weld center line. This paper evaluates the TSC of X42 vintage pipeline by utilizing ductile fracture mechanics models using damage plasticity models in ABAQUS extended finite element method (XFEM). The damage parameters required for simulating crack initiation and propagation in X42 vintage pipeline are calibrated numerically by comparing the numerical models with the full-scale test results. With the appropriate damage parameters, the numerical model can reasonably reproduce the full-scale experimental test results and can be used to carry out parametric analysis to characterize the effect of internal pressure and flaw size on TSC of X42 vintage pipes.

scholarly journals Loss assessment of building and content damages from potential earthquake risk in Seoul, Korea

2018 ◽  
Author(s):  
Wooil Choi ◽  
Jae-Woo Park ◽  
Jinhwan Kim
Keyword(s):  
Seismic Design ◽  
Korean Peninsula ◽  
Financial Stability ◽  
Building Code ◽  
Earthquake Risk ◽  
Design Code ◽  
Loss Assessment ◽  
Damage State ◽  
Damage Functions ◽  
Seismic Design Code

Abstract. After the 2016 Gyeongju earthquake and the 2017 Pohang earthquake struck the Korean peninsula, securing financial stability for earthquake risk has become an important issue in Korea. Many domestic researchers are currently studying potential earthquake risk. However, empirical analysis and statistical approach are ambiguous in the case of Korea because no major earthquake has ever occurred on the Korean peninsula since Korean Meteorological Agency started monitoring earthquakes in 1978. This study focuses on evaluating possible losses due to earthquake risk in Seoul, the capital of Korea, by using catastrophe model methodology integrated with GIS (Geographic Information System). The building information such as structure and location is taken from the building registration database and the replacement cost for building is obtained from insurance information. As the seismic design code in KBC (Korea Building Code) is similar to the seismic design code of UBC (Uniform Building Code), the damage functions provided by HAZUS-MH are used to assess the damage state of each building in event of an earthquake. 12 earthquake scenarios are evaluated considering the distribution and characteristics of active fault zones in the Korean peninsula, and damages with loss amounts are calculated for each of the scenarios.

Seismic Proving Test of Eroded Piping: Status of Eroded Piping Component and System Test

2003 ◽  
Author(s):  
Y. Namita ◽  
K. Suzuki ◽  
H. Abe ◽  
I. Ichihashi ◽  
M. Shiratori ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Ultimate Strength ◽  
Seismic Design ◽  
Plastic Response ◽  
Design Code ◽  
Seismic Safety ◽  
Testing Program ◽  
Safety Margins ◽  
Seismic Design Code ◽  
Piping Systems

In FY 2000, a 3-year testing program of eroded piping was initiated with the following objectives: 1) to ascertain the seismic safety margins for eroded piping designed under the current seismic design code, 2) to clarify the elasto-plastic response and ultimate strength of eroded nuclear piping. A series of tests on eroded piping components and eroded piping systems was planned. In this paper, the results of those tests are presented and analyzed, focusing on the influence of the form and the number of thinned-wall portions on the fatigue life of the piping.

Large Scale Tests of Strain Capacity of Pipe Sections With Circumferential Defects Subjected to Installation-Induced Plastic Strain History

2009 ◽  
Author(s):  
Ba˚rd Nyhus ◽  
Erling O̸stby ◽  
Zhiliang Zhang ◽  
Erlend Olso̸ ◽  
Per Arne Ro̸stadsand ◽  
...  
Keyword(s):  
Large Scale ◽  
Base Material ◽  
Bending Moment ◽  
Full Scale ◽  
Strain History ◽  
Strain Capacity ◽  
Four Point Bending ◽  
Full Scale Tests ◽  
Circumferential Defects ◽  
Large Scale Tests

Installation of offshore pipelines by reeling introduces plastic pre-straining. The pre-strain history is not homogenous and it will vary around the circumference of the pipe. The pre-strain history will modify the yield and flow properties. Also, the fracture toughness may be influenced by the pre-straining. The result is that the bending strain capacity of pipelines during operation will differ depending on how the bending moment coincides with pipe orientation during installation. Three full scale tests of 12″ x-60 pipes with wall thickness 19.3mm and a 3×100 mm outer surface defect were performed to investigate the effect of pre-strain history. Two pipes were pre-strained in bending to 2% strain in the outer fibre and then straightened to simulate the reeling. The final tests to establish the strain capacity during operation as a function of strain history were performed in four point bending with an internal pressure of 325 bar. The strain capacity for the side of the pipe that ends in tension and the side that ends in compression from pre-straining was 1.7% and 2.6% respectively. The strain capacity of the third test without pre-straining was 5.7%. The results show that pre-straining will modify the strain capacity and the effect must be taken into account in engineering critical assessment of pipes during operation. The effect of prestraining should be evaluated for all installation methods that involve plastic deformation during installation, and not only reeling. It is important to note that the notch size in the full scale tests was larger than what would normally be accepted for reeling. In addition the notch was positioned in base material and not in weld metal, which is a more realistic position for a notch. The welds are normally overmatched and this might reduce the effect of prestraining.

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