Pipe Deformation During a Running Shear Fracture in Line Pipe

1974 ◽  
Vol 96 (4) ◽  
pp. 309-317 ◽  
Author(s):  
K. D. Ives ◽  
A. K. Shoemaker ◽  
R. F. McCartney
Keyword(s):  
Circumferential Strain ◽  
Shear Fracture ◽  
Large Diameter ◽  
Crack Tip ◽  
Local Pressure ◽  
Pipe Length ◽  
Line Pipe ◽  
Iron And Steel ◽  
Pressure Transducers ◽  
Propagating Shear

Under sponsorship of the American Iron and Steel Institute, U. S. Steel Research has been conducting full-scale burst tests of large-diameter submerged-arc-welded line pipe to determine the toughness required to arrest running shear fractures for different design conditions. As part of that program, the pipe were instrumented with crack detectors, strain gages, and pressure transducers to determine the crack velocities and the actual pipe deformation and strain fields associated with the shear fracture propagating along the top of the pipe. This paper summarizes the test data that document the manner in which the pipe deforms during this type of crack propagation. The data show that for a propagating shear fracture, each of four different locations along the pipe length (relative to the crack tip) has a distinctive type of pipe deformation. For a location many pipe diameters ahead of the crack tip, the circumferential strain first decreases because of flexural waves associated with the initiation process and then continues to decrease in proportion to the local gas decompression; however, the longitudinal strain continuously increases because of a longitudinal “tongue” of tensile straining on the top of the pipe caused by pressure-induced opening of the flaps of the pipe on both sides of the fracture behind the crack tip. At a distance about two diameters ahead of the crack tip, the pipe cross section becomes oval, and in the presence of this deformation the strain field is no longer determined by the local pressure; in fact, the circumferential strain is near zero at a distance two diameters ahead of the crack. The oval pipe shape ahead of the crack tip is caused by the venting of the gas behind the crack tip which creates a downward reactive force on the bottom portion of the pipe. Opening at the crack tip is the result of tensile straining caused by circumferential and radial displacement of the flaps behind the crack tip. Thus it is believed that the action of the pipe-wall flaps behind the crack tip provides the primary force driving the crack down the top of the pipe.

Displacement Consideration for a Ductile Propagating Fracture in Line Pipe

1974 ◽  
Vol 96 (4) ◽  
pp. 318-322 ◽  
Author(s):  
A. K. Shoemaker ◽  
R. F. McCartney
Keyword(s):  
Driving Force ◽  
Driving Forces ◽  
Pipe Wall ◽  
Shear Fracture ◽  
Crack Tip ◽  
Complex Problem ◽  
Empirical Correlations ◽  
Line Pipe ◽  
Velocity Of Propagation ◽  
Propagating Shear

To date, the technically complex problem of arriving at an analysis for a running shear fracture in a gas-transmission line pipe has been primarily viewed by investigators in terms of an energy balance that involves empirical correlations of data. In contrast, in the present paper, the problem is reviewed in terms of the forces, masses, and time involved in the fracturing event and the resultant accelerations, velocities, and displacements with respect to (1) the forces driving the crack, (2) the pipe-wall ductility resisting the driving forces, and (3) the manner in which the crack arrests. Special attention is given to the effects of backfill on these events. On the bases of the data available, it is proposed that the displacements developed by the driving force are the result of the acceleration developed by the pressure acting on the flaps behind the crack. The driving force developed by the flaps results in forces which open the crack. For a constant velocity of propagation, the time for this flap displacement corresponds to the time for the pipe-wall thinning at the crack tip, which is controlled by the pipe-wall ductility. Thus, pipe-wall ductility can limit the speed of the crack. At a low crack speed, sufficient radial displacement of the flaps behind the crack occurs to cause the crack to turn in a helical path and arrest. Finally, the backfill significantly decreases the driving force and thus reduces the pipe-wall ductility necessary for arrest. Therefore, considerations of the displacements which occur during a propagating shear fracture indicate that the time and forces required for thinning the material at the crack tip, which is essentially governed by the ductility of the pipe wall, limit the speed of the crack.

Shear Fracture Arrestability of Controlled Rolled Steel X70 Line Pipe by Full-Scale Burst Test

1984 ◽  
Vol 106 (1) ◽  
pp. 55-62 ◽  
Author(s):  
E. Sugie ◽  
H. Kaji ◽  
T. Taira ◽  
M. Ohashi ◽  
Y. Sumitomo
Keyword(s):  
Shear Fracture ◽  
High Strength ◽  
Full Scale ◽  
Research Committee ◽  
Line Pipe ◽  
Iron And Steel ◽  
Propagation Behavior ◽  
Velocity Relationship ◽  
On Line ◽  
Propagating Shear

The High Strength Line Pipe Research Committee organized by the Iron and Steel Institute of Japan has conducted five full-scale burst tests on line pipe of 48 in. o.d. × 0.720 in. w.t. (wall thickness) and grade X70 under pressure of 80 percent SMYS with air: 1) to study the influence of separation on the arrestability of shear fracture, and 2) to obtain the material criterion for arresting the propagating shear fracture. Test pipes of Charpy V notch energy from 80 to 290J with different amount of separation, were produced from both controlled rolled steels and quenched and tempered steels. These research projects clarified that the separation of material itself did not influence the crack propagation behavior and its arrestability. Furthermore, the material criterion for arresting the shear fracture was analyzed by the pressure-velocity relationship counterbalancing the crack velocity curve and gas decompression curve.

scholarly journals On the Propagating Shear Fracture in Large Diameter Gas Pipeline

1978 ◽  
Vol 64 (7) ◽  
pp. 958-968 ◽  
Author(s):  
Takahide TANAKA ◽  
Minoru FUKUDA ◽  
Izumi TAKEUCHI ◽  
Toshiaki KOGA
Keyword(s):  
Shear Fracture ◽  
Large Diameter ◽  
Gas Pipeline ◽  
Propagating Shear

Notch Ductilities of Rich Natural Gas Transmission Line Pipes for Arresting Propagating Shear Fracture

1987 ◽  
Vol 109 (1) ◽  
pp. 2-8 ◽  
Author(s):  
E. Sugie ◽  
M. Matsuoka ◽  
T. Akiyama ◽  
K. Tanaka ◽  
Y. Kawaguchi
Keyword(s):  
Natural Gas ◽  
Crack Velocity ◽  
Shear Fracture ◽  
High Strength ◽  
Velocity Curve ◽  
Research Committee ◽  
Velocity Change ◽  
Charpy Test ◽  
Line Pipe ◽  
Propagating Shear

High Strength Line Pipe Research Committee organized by The Iron and Steel Institute of Japan carried out two full-scale burst tests on X70 line pipes, 48 in. o.d. × 0.720 in. w.t., with rich natural gas as the pressurizing gas. A theoretical investigation which gives the crack velocity change in terms of the crack velocity curve and the gas decompression velocity curve is presented, and the theoretical predictions and the experimental results are in good agreement. The developed method can predict the required notch ductilities obtained from Charpy test and DWTT in order to arrest a propagating shear fracture according to the type of gas, design stress and acceptable fracture length in the pipeline.

scholarly journals Propagating Shear Fracture Test of Large Diameter Gas Transmission Line Pipes for Arctic Grade

1976 ◽  
Vol 62 (6) ◽  
pp. 688-695 ◽  
Author(s):  
Eiji MIYOSHI ◽  
Takahide TANAKA ◽  
Minoru FUKUDA ◽  
Hiroshi IWANAGA ◽  
Tooru OKAZAWA
Keyword(s):  
Transmission Line ◽  
Shear Fracture ◽  
Large Diameter ◽  
Fracture Test ◽  
Propagating Shear

Analysis of Data From a Full-Scale Burst Test on 1219 mm OD Grade 550 Pipe: Implications for the Prediction of Fracture Velocity

2016 ◽  
Author(s):  
Brian Rothwell ◽  
Cindy Guan ◽  
Satoshi Igi
Keyword(s):  
Traditional Approach ◽  
Large Diameter ◽  
Crack Tip ◽  
Management Program ◽  
Full Scale ◽  
Correction Factors ◽  
Long Distance ◽  
Line Pipe ◽  
Fracture Arrest ◽  
Fracture Velocity

In recent years, considerable doubt has arisen over the prediction of the level of toughness required to arrest a propagating fracture in higher-strength line pipe. It has been clear for many years that the most widely used traditional approach, the Two-Curve Method (TCM) developed at Battelle in the early 1970s, could not be applied directly when the required toughness, expressed as full-size Charpy energy, exceeded about 80–90 J. Initially, this issue was addressed by the adoption of empirical correction factors, but more recently, there have been indications that this approach is no longer effective for modern, high-strength materials. Additional information, which in general can only be derived from well-characterized burst tests, is essential to furthering understanding of the fracture arrest problem under conditions that are typical of modern, long-distance, large-diameter pipeline design. In the context of the Coastal GasLink (CGL) project, TransCanada has carried out a program of full-scale burst testing at the Spadeadam test site of DNV GL. The tests were supported by LNG Canada and the TransCanada Technology Management Program. These tests are described in another paper at this conference [1]. Though most of the testing was directed towards the assessment of different crack arrestor designs, one half of one test contained a run of four pipes of progressively increasing Charpy energy, up to a very high level (over 450 J). The fracture was observed to run through all four pipes, before being arrested by a crack arrestor fitted to a fifth pipe having lower toughness. Nearly all approaches to determining requirements for fracture arrest depend, directly or indirectly, on relationships between fracture velocity (for given levels of fracture resistance) and the driving force, generally considered to be directly related to the pressure in the plane of the crack tip. By comparing measured fracture velocity with the crack tip pressure determined either directly at pressure transducer locations or by comparison with propagation velocities within the expansion wave, conclusions can be drawn regarding the accuracy of existing relationships. Most previous work regarding correction factors has been based simply on discrepancies between predicted and observed propagation and arrest behaviour. Direct comparisons of observed and predicted fracture speed potentially provide much more data and focus more clearly on where model deficiencies may lie. The current analysis focuses on comparisons with the predictions of the traditional TCM and those of a transient model developed by JFE. While data from the present work are clearly limited, this approach appears to present a way of recalibrating fracture velocity formulations that may extend the range over which traditional, Charpy-based approaches can be applied. For the future, the incorporation of additional results from other recent, well-characterized burst tests would be extremely valuable in this respect.

Development of X80M Line Pipe Steel for Spiral Welded Pipes With Low Temperature Toughness and Excellent Weldability

2014 ◽  
Author(s):  
Nuria Sanchez ◽  
Özlem E. Güngör ◽  
Martin Liebeherr ◽  
Nenad Ilić
Keyword(s):  
Low Temperature ◽  
Life Cycle Cost ◽  
Volume Fraction ◽  
Large Diameter ◽  
Pipe Production ◽  
Strain Accumulation ◽  
Long Distance ◽  
Line Pipe ◽  
Low Temperature Toughness ◽  
Welded Pipe

The unique combination of high strength and low temperature toughness on heavy wall thickness coils allows higher operating pressures in large diameter spiral welded pipes and could represent a 10% reduction in life cycle cost on long distance gas pipe lines. One of the current processing routes for these high thickness grades is the thermo-mechanical controlled processing (TMCP) route, which critically depends on the austenite conditioning during hot forming at specific temperature in relation to the aimed metallurgical mechanisms (recrystallization, strain accumulation, phase transformation). Detailed mechanical and microstructural characterization on selected coils and pipes corresponding to the X80M grade in 24 mm thickness reveals that effective grain size and distribution together with the through thickness gradient are key parameters to control in order to ensure the adequate toughness of the material. Studies on the softening behavior revealed that the grain coarsening in the mid-thickness is related to a decrease of strain accumulation during hot rolling. It was also observed a toughness detrimental effect with the increment of the volume fraction of M/A (martensite/retained austenite) in the middle thickness of the coils, related to the cooling practice. Finally, submerged arc weldability for spiral welded pipe manufacturing was evaluated on coil skelp in 24 mm thickness. The investigations revealed the suitability of the material for spiral welded pipe production, preserving the tensile properties and maintaining acceptable toughness values in the heat-affected zone. The present study revealed that the adequate chemical alloying selection and processing control provide enhanced low temperature toughness on pipes with excellent weldability formed from hot rolled coils X80 grade in 24 mm thickness produced at ArcelorMittal Bremen.

Buckling Resistance of Large Diameter Spiral Welded Linepipe

2004 ◽  
Author(s):  
Tom Zimmerman ◽  
Chris Timms ◽  
Jueren Xie ◽  
James Asante
Keyword(s):  
Oil And Gas ◽  
Weld Seam ◽  
Large Diameter ◽  
Ground Movement ◽  
Finite Element Analyses ◽  
Line Pipe ◽  
Diameter Pipe ◽  
Buckling Resistance ◽  
Analytical Research ◽  
Full Scale Tests

This paper contains the results of an experimental and analytical research program to determine the compressive buckling resistance of large-diameter, spiral-welded linepipe. Buckling resistance is important for pipe intended for service in Arctic, oil and gas pipeline systems, where pipes may be subjected to high bending strains caused by various ground movement events. The experimental work consisted of four full-scale tests of 30-inch (762 mm) diameter pipe subjected to various combinations of internal pressure, axial force and bending. The pipe specimens were fabricated using two material grades (X70 and X80) and two D/t ratios (82 and 48). Finite element analyses of the four tests were conducted to develop a better understanding of specimen behavior. The results suggest that spiral welded linepipe is as good as longitudinally welded line pipe in terms of buckling capacity. The spiral weld seam was in no way detrimental to the pipe performance.

Large-Diameter Line Pipe Expanding Process

2012 ◽  
Vol 192 ◽  
pp. 180-184 ◽  
Author(s):  
Ai Xia He ◽  
Rong Chang Li
Keyword(s):  
Process Parameters ◽  
Large Diameter ◽  
Dimensional Accuracy ◽  
Optimization Method ◽  
Main Process ◽  
Shape Accuracy ◽  
Line Pipe ◽  
Factors Affecting ◽  
Array Optimization

Mechanical expanding process for large diameter line pipe, a detailed analysis of factors affecting the quality of the final products of the mechanical expansion and proposed optimization using orthogonal array optimization method, as an indicator of dimensional accuracy and shape accuracy of the products, combination of a variety of specifications of mechanical expanding products, the main process parameters to be optimized. Analysis and discussion of results, revealing the degree of influence of various factors on the quality of the final product, and gives the optimum combination of the results. Experiments show that the combination of optimized process parameters, and more help to improve the accuracy of the size and shape of products.

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