Simulation of Dynamic Crack Propagation and Arrest Using Various Types of Crack Arrestor

2016 ◽  
Author(s):  
Mohammed Uddin ◽  
Gery Wilkowski
Keyword(s):  
Crack Propagation ◽  
Large Diameter ◽  
Small Diameter ◽  
Full Scale ◽  
Fe Model ◽  
Ductile Crack ◽  
Burst Test ◽  
Ductile Crack Growth ◽  
Diameter Pipe ◽  
Linepipe Steels

In linepipe steels, there has been a growing interest in using damage mechanics that provides physical models of the fracture process which are embedded into a two- or three-dimensional finite element (FE) model. Among the various damage models, the cohesive zone model (CZM) has recently been used to simulate the ductile crack growth behavior in linepipe steels because of its computational efficiency and it requires only two parameters which can be determined in experiments. While CZM is not yet to be used as predictive tool, but it has a great application in crack arrestor design as well as in providing insight to ductile crack propagation. In this paper, the authors have demonstrated some practical applications of CZM in linepipe steels. The CZM was used to simulate the ductile crack propagation in full-scale pipes which was able to capture the global deformation as well as the experimental crack speed. The model was then used to determine the effect of anchor blocks at the end of the pipe in a large diameter full-scale burst test. Later, the model was used to simulate two small diameter pipe tests with steel crack arrestors to mimic two arrestor cases with one showing crack propagation and the other showing crack arrest. The CZM model was also applied to demonstrate the circumferential ring-off behavior of a small diameter pipe test with rigid crack arrestor. The arrestor model was then extended to simulate a large diameter full scale Mojave burst test with “soft crack arrestor (SCA)”. A single element FE model was developed to verify the SCA material which was later extended with stain-based failure criteria. Finally, ductile crack growth in full-scale pipe with SCA was demonstrated to show that the FE CZM model can be used to optimize the design of SCA.

Brittle Crack Arrestability and Inverse Fracture in DWTT

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Takahiro Sakimoto ◽  
Toshihiko Amano ◽  
Takashi Hiraide ◽  
Tetsuya Tagawa ◽  
Satoshi Igi ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Test Temperature ◽  
Crack Arrest ◽  
Ductile Crack ◽  
Brittle Crack ◽  
Burst Test ◽  
Shear Area ◽  
Linepipe Steels ◽  
Temperature Test ◽  
Test Stress

Abstract The drop-weight tear test (DWTT) has been widely used to evaluate the resistance of linepipe steels against brittle crack propagation, and the shear area fraction SA% in the DWTT has been adopted in the requirement for the linepipe steels. However, recent studies have pointed out the issue of ambiguity in evaluation of the DWTT when a ductile crack initiates from the notch and then transits to a brittle crack during ductile crack propagation. This fracture behavior is termed “inverse fracture.” According to the API Recommended Practice 5L3 (API RP 5L3), a test is considered invalid when a DWTT specimen shows inverse fracture. In this case, it is difficult to examine the acceptance criterion (85% shear area transition temperature) for linepipe steels. Because the purpose of the DWTT is to evaluate the brittle crack arrestability of the steels in a pressurized linepipe, the DWTT results should be examined with a propagating brittle crack arrest test. A large-scale brittle crack arrest test called the West Jefferson test is generally conducted to reproduce the crack propagation and arrest behavior in actual linepipes. However, it is somewhat difficult to control the lower test temperature and to initiate brittle crack in recent high-toughness steels in this burst test. Although the test stress conditions of the uniaxial tension in the plate tension brittle crack arrest test and the biaxial tension in a pressurized pipe are different, the plate tension brittle crack arrest test has the advantages of accurate control of the test temperature, test stress, and brittle crack initiation in comparison with the actual pipe burst test. Therefore, in this study, the brittle crack arrestability of linepipe steel which showed inverse fracture in the DWTT was investigated by conducting plate tension brittle crack arrest tests under an isothermal condition (crack arrest temperature test (CAT test)), which simulates the condition of the actual pipelines in service. This study also investigated the local shear lip thickness fraction in the CAT tests together with the shear area fraction SA% measured in DWTTs. Based on the results, the effect of brittle crack arrestability on inverse fracture appearance in the DWTTs was discussed in comparison with the brittle crack arrest behavior in the CAT tests.

Design of crack arrestors for ultra high grade gas transmission pipelines: simulation of crack initiation, propagation and arrest

2011 ◽  
Vol 2 (2) ◽  
pp. 307-319
Author(s):  
F. Van den Abeele ◽  
M. Di Biagio ◽  
L. Amlung
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Large Scale ◽  
Large Diameter ◽  
Pipe Material ◽  
High Grade ◽  
Gas Pipelines ◽  
Ductile Crack ◽  
Reinforced Plastics ◽  
Four Point Bending

One of the major challenges in the design of ultra high grade (X100) gas pipelines is the identification of areliable crack propagation strategy. Recent research results have shown that the newly developed highstrength and large diameter gas pipelines, when operated at severe conditions, may not be able to arrest arunning ductile crack through pipe material properties. Hence, the use of crack arrestors is required in thedesign of safe and reliable pipeline systems.A conventional crack arrestor can be a high toughness pipe insert, or a local joint with higher wall thickness.According to experimental results of full-scale burst tests, composite crack arrestors are one of the mostpromising technologies. Such crack arrestors are made of fibre reinforced plastics which provide the pipewith an additional hoop constraint. In this paper, numerical tools to simulate crack initiation, propagationand arrest in composite crack arrestors are introduced.First, the in-use behaviour of composite crack arrestors is evaluated by means of large scale tensile testsand four point bending experiments. The ability of different stress based orthotropic failure measures topredict the onset of material degradation is compared. Then, computational fracture mechanics is applied tosimulate ductile crack propagation in high pressure gas pipelines, and the corresponding crack growth inthe composite arrestor. The combination of numerical simulation and experimental research allows derivingdesign guidelines for composite crack arrestors.

Evaluation of Residual Stresses Induced by Repairs to Small Diameter Stainless Steel Pipe Welds

2015 ◽  
Author(s):  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller ◽  
John V. Mullen
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Large Diameter ◽  
Small Diameter ◽  
Steel Pipe ◽  
Limited Information ◽  
Diameter Pipe ◽  
Stainless Steel Pipe ◽  
Lower Magnitude ◽  
The Impact

Residual stresses within stainless steel pipe welds may cause or exacerbate in-service cracking. Significant investigative efforts have been devoted to the examination of piping residual stresses in large diameter piping using both finite element modeling and experimental techniques, but limited information is available for small diameter piping. Even less information is available for small diameter piping welds which have been repaired or re-worked during initial fabrication. This investigation used both experimental methods and analytical modeling to assess the impact of repair welding during initial fabrication on the residual stresses along the inner diameter (ID) of small diameter pipe specimens. The investigation showed that tensile axial residual stresses were located in the heat affected zone (HAZ) along the ID of the pipe specimens adjacent to regions which were excavated and re-welded. Such repair welds were also shown to markedly increase the magnitude of the tensile axial residual stresses for weld configurations which otherwise had lower magnitude residual stresses.

Ductile Fracture Simulation of CRIEPI STPT 410 Pipe With Circumferential Crack

2014 ◽  
Author(s):  
Hyun-Suk Nam ◽  
Young-Ryun Oh ◽  
Jae-Jun Han ◽  
Chang-Young Oh ◽  
Yun-Jae Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Crack Growth ◽  
Fracture Strain ◽  
Damage Model ◽  
Full Scale ◽  
Ductile Crack ◽  
Size Dependent ◽  
Element Size ◽  
Ductile Crack Growth ◽  
Strain Model

This paper provides simulation of ductile crack growth in full-scale cracked pipe tests using an element-size dependent damage model. This method is based on the stress-modified fracture strain damage model. The stress-modified fracture strain model is determined to be incremental damage in terms of stress triaxiality and fracture strain for dimple fracture from tensile test result with FE analyses technique. To validate the proposed method, this research analyses STPT 410 cracked pipes test at 300°C taken from CRIEPI (Central Research Institute of Electric Power Industry). In order to calibrate the stress-modified fractures strain model, tensile tests and fracture toughness tests were compared with simulated results using element-size dependent damage model. Tensile specimen and fracture toughness specimen were extracted from STPT 410 steel pipe. The calibrated damage model predicts ductile crack growth in 5 type circumferential cracked pipes bending test. And these results were compared with the experimental results. The results show that the proposed method can simulate ductile crack growth in full-scale cracked pipe tests.

Assessment of the Remaining Strength of Corroded Small Diameter (Below 6”) Pipelines and Pipework

2012 ◽  
Author(s):  
Troy Swankie ◽  
Vinod Chauhan ◽  
Robert Owen ◽  
Robert Bood ◽  
Geoffrey Gilbert
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Ductile Failure ◽  
Corrosion Damage ◽  
Full Scale ◽  
Alternative Methods ◽  
Low Grade ◽  
Numerical Work ◽  
Line Pipe ◽  
Failure Pressure

Internal and external corrosion damage is a major cause of pipeline failures worldwide. When corrosion features in pipelines are detected by in-line inspection (ILI), a decision whether to replace, repair or accept and monitor must be made. Extensive experimental and numerical work has been undertaken to develop methods for assessing the remaining strength of corroded transmission pipelines. Common methods used by the pipeline industry include ASME B31G, modified ASME B31G and LPC. These methods are semi-empirical and have been developed using a modified version of a toughness independent ductile failure criterion for pressurized pipes containing axially orientated surface breaking defects. The validity range of these models is dominated by large diameter (10 to 48″), thin walled, low grade (API 5L grade A to X65) and low yield to tensile ratio line pipe. Smaller diameter (not greater than 6″), thick walled pipelines and pipework located, for example, at above ground installations, compressor and pressure reduction stations are very common. The use of ASME B31G, modified ASME B31G or LPC may not be appropriate when assessing the remaining strength of small diameter pipelines and pipework. No alternative methods are available in the public domain and hence a program of work was undertaken to derive appropriate defect acceptance limits by conducting a series of full-scale burst tests on small diameter pipe with simulated corrosion defects. It was concluded that the LPC method gave the most accurate prediction of failure pressure when compared with the results of the full-scale tests, and the most conservative predictions of failure pressure were obtained using the ASME B31G method.

Numerical Simulation of Dynamic Ductile Fracture Propagation Using Cohesive Zone Modeling

2008 ◽  
Author(s):  
Do-Jun Shim ◽  
Gery Wilkowski ◽  
David Rudland ◽  
Brian Rothwell ◽  
James Merritt
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Crack Growth ◽  
Growth Model ◽  
Cohesive Zone ◽  
Zone Model ◽  
Pipe Material ◽  
Ductile Crack ◽  
Ductile Crack Growth ◽  
Crack Growth Model

This paper presents the development of a dynamic ductile crack growth model to simulate an axially running crack in a pipe by finite element analyses. The model was developed using the finite element (FE) program ABAQUS/Explicit. To simulate the ductile crack propagation, a cohesive zone model was employed. Moreover, the interaction between the gas decompression and the structural deformation was simulated by using an approximate three-dimensional pressure decay relationship from experimental results. The dynamic ductile crack growth model was employed to simulate 152.4 mm (6-inch) diameter pipe tests, where the measured fracture speed was used to calibrate the cohesive model parameters. From the simulation, the CTOA values were calculated during the dynamic ductile crack propagation. In order to validate the calculated CTOA value, drop-weight tear test (DWTT) experiments were conducted for the pipe material, where the CTOA was measured with high-speed video during the impact test. The calculated and measured CTOA values showed reasonable agreement. Finally, the developed model was employed to investigate the effect of pipe diameter on fracture speed for small-diameter pipes.

On the Collapse Pressure of Impanded Large Diameter Pipe (JCO-C)

2012 ◽  
Author(s):  
Thilo Reichel ◽  
Vitaliy Pavlyk ◽  
Jochem Beissel ◽  
Ivan Aretov ◽  
Stelios Kyriakides
Keyword(s):  
Heat Treatment ◽  
Large Diameter ◽  
Full Scale ◽  
Compressive Yield Strength ◽  
Perfect Agreement ◽  
Collapse Pressure ◽  
Large Diameter Pipe ◽  
Diameter Pipe ◽  
Improved Performance ◽  
Welded Pipe

Current manufacturing technology for large diameter pipe, such as the UOE process, is known to result in pipe with reduced collapse pressure compared to a seamless one of the same steel grade and D/t. It has recently been demonstrated [1,2] that such deficient performance can be alleviated by finishing longitudinally welded pipe by compression. A newly developed cold sizing press, called Impander®, is used to produce pipe with reduced ovality, reduced residual stresses and increased compressive yield strength. The combination of these factors can lead to a significant increase in the collapse pressure of the pipe. The paper will review experimental and analytical results that demonstrate the improved collapse pressure of pipes manufactured by it. This improved performance was confirmed in a full-scale collapse experiment on a pipe finished by impansion of 1.1%. The test showed perfect agreement with the modelling. The collapse pressure was 37% higher than current design codes allow. Additional work has been performed aimed at evaluating the effect of low temperature heat treatment on the collapse pressure. A full-scale collapse test on impanded and heat-treated pipe has shown that a significant additional enhancement in collapse pressure results from the heat treatment. The paper will discuss the thermomechanical causes of these enhancements of the collapse pressure.

scholarly journals Arctic Linepipe With High Resistance to Crack Propagation and HIC

1996 ◽  
Author(s):  
Gregorio R. Murtagian ◽  
Guillermo L. Fitzsimons ◽  
Juan C. González ◽  
Irina S. Kotova ◽  
Nikoli I. Anenkov
Keyword(s):  
Crack Propagation ◽  
Large Diameter ◽  
Propagation Speed ◽  
Unstable Crack ◽  
Computer Data ◽  
Computer Data Acquisition ◽  
Hydrogen Induced Cracking ◽  
Crack Propagation Speed ◽  
Linepipe Steels ◽  
Work Done

Linepipe steels for sour, arctic and offshore applications, form a class of material by themselves. These linepipes are originated in the need to fulfill several special characteristics like adequacy for induction bending, toughness requirement at very low temperature to prevent a unstable crack propagation, and hydrogen induced cracking resistance. These kind of linepipes are produced through clean steel practice, resulting in a low residuals content and a low non metallic inclusions rating. It is also very important to get a fine and uniform microstructure to guarantee good performance under sour environments, arctic and offshore conditions. In the present paper, a practical test to assess fitness for service of special linepipes is presented. Two linepipes with diameters between 219 and 273 mm and Diameter/thickness (D/t) ratios from 10 to 20, intended for arctic service were studied. While linepipe of both large Diameter and D/t (above 50), have been studied, there has been very little work done for diameters below 420 mm and D/t ratios in the range of 10–20. Full scale burst tests at −40°C and −60°C were carried out under controlled conditions. Actual crack propagation speed during burst tests at temperatures below −60°C, was tracked through an oscilloscope-computer data acquisition system. Weldability and hydrogen induced cracking performances were also studied.

Dynamic Ductile Tearing in High Strength Pipeline Steels

1996 ◽  
Author(s):  
F. Rivalin ◽  
A. Pineau
Keyword(s):  
Crack Propagation ◽  
High Strength Steels ◽  
High Strength ◽  
Pearlitic Steel ◽  
Crack Arrest ◽  
Full Scale ◽  
Ductile Crack ◽  
Safety Level ◽  
Dynamic Conditions ◽  
Pipe Burst

The study of rapid ductile crack propagation and crack arrest is a central point if one wants to reach a higher safety level in pipelines. Correlations between Charpy tests and full scale burst tests proved to be unsuccessful in predicting pipe burst for recent high strength steels. This paper presents an experiment which allows to test large SENT specimens under dynamic loading, and to characterize steel resistance against rapid ductile crack propagation by a classical energetic parameter, called the crack propagation energy, R, proposed by Turner. The R parameter proved to be characteristic of the rapid crack propagation in the material, for a given specimen and loading configuration. Failure of the specimen under dynamic conditions occurs by shearing fracture which is the same as in a full scale burst test. An example is given for an X65 ferritic-pearlitic steel loaded under static and dynamic conditions. A fracture mode transition is shown following the loading rate. From a metallurgical point of view, shearing fracture occurs by nucleation, growth and coalescence of voids, as for classical ductile fracture.

Fracture Resistance in Line Pipe

1965 ◽  
Vol 87 (3) ◽  
pp. 265-278 ◽  
Author(s):  
G. M. McClure ◽  
A. R. Duffy ◽  
R. J. Eiber
Keyword(s):  
Fracture Behavior ◽  
Large Diameter ◽  
Full Scale ◽  
Laboratory Studies ◽  
Research Committee ◽  
Line Pipe ◽  
Diameter Pipe ◽  
On Line ◽  
Fracture Tests ◽  
Scale Behavior

The program of research on line pipe under the sponsorship of the A.G.A. Pipeline Research Committee is a comprehensive effort to investigate the important properties of pipe used in gas transmission. Several different phases are involved in this project, ranging from fundamental laboratory studies to fracture-behavior experiments on large-diameter pipe. This paper discusses the full-scale experimental parts of the program in which the fracture toughness of line pipe is being studied. Some of the factors that influence full-scale fracture behavior are discussed—material properties, fracture speed, temperature, wall thickness, nominal stress level, and type of backfill. Laboratory fracture tests that are being run and correlated with full-scale behavior are also described.

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