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.

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.

Fracture Propagation and Arrest in High-Pressure Gas Transmission Pipeline by Ultra High Strength Line Pipes

2008 ◽  
Author(s):  
Hiroyuki Makino ◽  
Izumi Takeuchi ◽  
Ryouta Higuchi
Keyword(s):  
High Pressure ◽  
Crack Velocity ◽  
Shear Fracture ◽  
Fracture Propagation ◽  
High Strength ◽  
Initial Crack ◽  
Full Scale ◽  
Velocity Curve ◽  
Gas Pipelines ◽  
Energy Prediction

The fracture arrest of high pressure gas pipelines is one of the keen subjects for application of high strength line pipes. To examine the arrestability of high strength line pipes against crack propagation, several full scale fracture propagation tests have been conducted. The fracture propagation tests of X100 or X120 under high pressure revealed that the existing models of arrest energy prediction failed to predict the arrest energies. By careful investigations of the test results, it is found that the failure in prediction is mainly due to the uncertainty of crack velocity curve prediction. On the other hand, accuracy of predicted gas decompression curve is relatively high even in the case of high pressure condition. Experimentally, the arrest energies have been determined by full-scale fracture propagation tests with increasing toughness arrangement. Different from actual pipeline, extremely low toughness pipe has been employed in crack initiation pipe with intention of getting steady state propagation. However, arrestability of pipe might be underestimated in the increasing toughness arrangement test as the initial crack velocity increases. Together with recalibrated crack velocity curve, Sumitomo model (HLP method with Sumitomo’s crack velocity curve) predicts that even toughness arrangement, which is the case of real pipelines, could arrest the propagating shear fracture in high pressure gas pipelines by X100.

The Practical Application of Fracture Control to Natural Gas Pipelines

2008 ◽  
Author(s):  
K. A. Widenmaier ◽  
A. B. Rothwell
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
High Strength ◽  
Fracture Initiation ◽  
Opening Angle ◽  
Pipe Material ◽  
Design Factor ◽  
Line Pipe ◽  
Natural Gas Pipelines ◽  
Crack Tip Opening

The use of high strength, high design-factor pipe to transport natural gas requires the careful design and selection of pipeline materials. A primary material concern is the characterization and control of ductile fracture initiation and arrest. Impact toughness in the form of Charpy V-notch energies or drop-weight tear tests is usually specified in the design and purchase of line pipe in order to prevent large-scale fracture. While minimum values are prescribed in various codes, they may not offer sufficient protection in pipelines with high pressure, cold temperature, rich gas designs. The implications of the crack driving force arising from the gas decompression versus the resisting force of the pipe material and backfill are examined. The use and limitations of the Battelle two-curve method as the standard model are compared with new developments utilizing crack-tip opening angle and other techniques. The methodology and reasoning used to specify the material properties for line pipe are described and the inherent limits and risks are discussed. The applicability of Charpy energy to predict ductile arrest in high strength pipes (X80 and above) is examined.

Interactive Simulation of Gas Decompression and Crack Propagation in Natural Gas Transmission Pipelines

2002 ◽  
Author(s):  
Hiroyuki Makino ◽  
Yoshiaki Kawaguchi ◽  
Yoichiro Matsumoto ◽  
Shu Takagi ◽  
Shinobu Yoshimura
Keyword(s):  
Natural Gas ◽  
Crack Propagation ◽  
Shear Fracture ◽  
Interactive Simulation ◽  
Operating Pressure ◽  
Gas Temperature ◽  
Natural Gas Transmission ◽  
Propagating Shear ◽  
Fracture Arrest ◽  
Transmission Pipelines

In this paper, the propagating shear fracture in natural gas transmission pipelines is simulated by an interactive method between gas decompression and crack propagation. A rich gas which contains heavier hydrocarbons than methane is highlighted and the relation between the crack velocity and the distance is simulated for varied condition of pipelines. The results of simulation are shown in the relation between the fracture arrest distance and the toughness of the pipes used, and the effects of the difference in gas compositions, increase of the operating pressure and the change of the initial gas temperature are discussed. The results of the simulation make it clear that the rich gas increases the risk for long running fracture, the simple increase of the operating pressure by increasing the design factor causes long crack propagation, increase of the operating pressure by using higher grade pipes not always invites long crack propagation and lower temperature increases the fracture arrest distance in relatively lower pressure but decreases the distance in relatively higher pressure. All the discussion in this study indicates that the analysis of the decompression behavior of the inner gas is essential for the interpretation of the phenomenon of the propagating shear fracture in pipelines. It is concluded that the fluid characteristics of the gas transmitted and material characteristics of the pipes used should be matched appropriately for the safety of the pipelines.

Propagating Shear Fracture in Natural Gas Transmission Pipelines

2009 ◽  
pp. 237-237-10 ◽  
Author(s):  
E Sugie ◽  
M Matsuoka ◽  
T Akiyama ◽  
K Tanaka ◽  
M Tsukamoto
Keyword(s):  
Natural Gas ◽  
Shear Fracture ◽  
Natural Gas Transmission ◽  
Propagating Shear ◽  
Transmission Pipelines

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.

Evaluation of Compressive Strain Limit of X80 Saw Pipes With Girth Welding by FE Analysis

2010 ◽  
Author(s):  
Hidenori Shitamoto ◽  
Masahiko Hamada ◽  
Shuji Okaguchi ◽  
Nobuaki Takahashi ◽  
Izumi Takeuchi ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
High Strength ◽  
Environmental Conservation ◽  
Ground Movement ◽  
Bending Test ◽  
Line Pipe ◽  
Strain Capacity ◽  
Girth Welding ◽  
Transmission Pipelines

The expansion of supply capacity of natural gas to market is expected from the concern of environmental conservation by less CO2 emission. Transportation cost has been focused for natural gas to be competitive in the market. High-pressure gas pipelines have constructed by large diameter and high strength line pipes to improve transportation efficiency of gas transmission pipelines. High strength line pipes have been developed to cope with high-pressure operation. Strength in circumferential direction on line pipe is the prime target to hold high pressure safely. In terms of pipe size, pipe diameter has been increased to lead larger D/t. Both of higher strength and larger D/t result in less favorable to deformability of pipeline. To apply strain based design to pipeline, the evaluation of strain capacity, which is related to deformability of line pipe, is required supposing the pipeline encounters large scale ground movement such as earthquake or landslide. It is not simple to find the criteria to prevent leak or rupture of pipeline in such events, as not only pipe property but also interaction between pipe and soil are needed to consider. Gas transmission pipelines are constructed by joint girth welding. The strain capacity of pipeline with girth weld has to be investigated for strain based design. Full scale bending test of joint welded pipe was conducted and FEA model to assess strain capacity of pipeline with girth weld is developed.

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.

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