A Theoretical Model for Crack Propagation and Crack Arrest in Pressurized Pipelines

2009 ◽  
pp. 341-341-18 ◽  
Author(s):  
PA McGuire ◽  
SG Sampath ◽  
CH Popelar ◽  
MF Kanninen
Keyword(s):  
Theoretical Model ◽  
Crack Propagation ◽  
Crack Arrest ◽  
Pressurized Pipelines

Steady-State Crack Propagation in Pressurized Pipelines

1977 ◽  
Vol 99 (1) ◽  
pp. 112-121 ◽  
Author(s):  
C. Popelar ◽  
A. R. Rosenfield ◽  
M. F. Kanninen
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Driving Force ◽  
Crack Arrest ◽  
Operating Conditions ◽  
Unstable Crack ◽  
Crack Driving Force ◽  
Plastic Yield ◽  
Pressurized Pipelines ◽  
Full Scale Tests

Previous work at Battelle-Columbus on the development of a theoretical model for unstable crack propagation and crack arrest in a pressurized pipeline is extended in this paper by including the effect of backfill. The approach being developed involves four essential aspects of crack propagation in pipelines. These four components of the problem are: 1 – a shell theory characterization of the dynamic deformation of a pipe with a plastic yield-hinge behind an axially propagating crack, 2 – a fluid-mechanics treatment of the axial variations in the gas pressure acting on the pipe walls, 3 – an energy-based dynamic fracture mechanics formulation for the crack-driving force, and 4 – measured values of the dynamic energy absorption rate for pipeline steels. Comparisons given in the paper show that the steady-state crack speeds predicted by the model are in reasonably good agreement with the crack speeds measured in full-scale tests, both with and without backfill. The analysis further reveals the existence of a maximum steady-state crack-driving force as a function of the basic mechanical properties of the pipe steel and the pipeline goemetry and operating conditions. Quantitative estimates of this quantity provided by the model offer a basis for comparison with the empirical crack-arrest design criteria for pipelines developed by AISI, the American Gas Association, the British Gas Council, and British Steel. These are also shown to be in substantial agreement with the predictions of the model developed in this paper.

Short Crack Propagation Model Applied to Shot Peened Aluminium Alloys

2009 ◽  
Vol 65 ◽  
pp. 53-61 ◽  
Author(s):  
J. Solis ◽  
J. Oseguera-Peña ◽  
I. Betancourt
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Aluminium Alloys ◽  
Micromechanical Model ◽  
High Strength ◽  
Crack Arrest ◽  
Propagation Model ◽  
Safe Load ◽  
Compressive Residual Stresses

The Navarro-Rios micromechanical model was used to assess the bounds of two different damage zones: crack arrest region and crack propagation region of controlled shot peening (CSP) of high strength aluminium alloys. Performance of CSP in terms of fatigue resistance was investigated. This comparison indicated that CSP in terms of fatigue depends on the competition between its beneficial and detrimental products, i.e. surface roughness and compressive residual stresses respectively. The gathered information can be used for safe load determinations in design.

KIa Crack Arrest Toughness Assessment Using Thermal Shock on Notched Disks

2004 ◽  
Author(s):  
Me´jido Hajjaj ◽  
Ste´phane Bugat ◽  
Clotilde Berdin ◽  
Philippe Bompard
Keyword(s):  
Crack Propagation ◽  
Thermal Shock ◽  
Static Analysis ◽  
Thermal Analyses ◽  
Crack Arrest ◽  
The Finite Element Method ◽  
Wave Interference ◽  
Shock Experiment ◽  
T Values ◽  
Arrest Toughness

The aim of the study is to validate the KIa-T curve on a thermal shock experiment performed on a notched disk (DTSE) taken from a A533-B type steel. Several experiments have been performed. Non linear thermal analyses were carried out using the finite element method in order to obtain the full thermal field within the specimen during crack propagation. The results obtained are in excellent agreement with the experimental results. The DTSE is also interpretated in static terms to compare the obtained KIa (T) values with the limit curve. Finally, dynamic F.E. simulations allow to estimate the influence of dynamic effects in the DTSE and thus validate the methodology. According to the computations, the crack arrested when dK/da>0 and dKd/da = 0. The comparison between stress intensity factor computed from elastic-static analysis (or dynamic) and RCC-M code demonstrated the conservatism of the approach. Then static analysis is sufficient to analyse the result, since no wave interference with the crack propagation was identified.

Fracture and Crack Propagation Behavior of 560 MPa Microalloyed Pipeline Steel under Different Cooling Schedules

2017 ◽  
Vol 898 ◽  
pp. 1094-1102 ◽  
Author(s):  
Jin Hua Zhao ◽  
Dong Fang Li ◽  
Guo Yuan ◽  
Xue Qiang Wang ◽  
Rui Hao Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Crack Propagation ◽  
Pipeline Steel ◽  
Crack Arrest ◽  
Dominant Factor ◽  
Cooling Schedules ◽  
Effective Grain Size ◽  
Mixed Microstructure ◽  
Low Temperature Toughness

Three kinds of pipeline steel with different microstructures were fabricated by varying cooling schedules during thermo-mechanical controlled processing (TMCP). Charpy impact property of the pipeline steels were obtained, and the fracture and crack-arrest mechanisms were further studied. The results indicated that the steels were classified into two kinds according to their microstructures, the mixture of acicular ferrite (AF), quasi-polygonal ferrite (QF), granular bainite (GB) and small fraction of degenerate pearlite (DP), and the mixed microstructure of AF and GB, respectively. The processed steel with microstructure of AF and GB exhibited more excellent low-temperature toughness and crack-arrest properties with upper shelf energy of ~281 J and energy transition temperature of ~-76°C. The mixed microstructure (AF + GB) possessing smaller effective grain size hindered the propagating of crack and consumed large amount of energy during fracture. The effective grain size of microstructure was the dominant factor controlling low-temperature toughness and crack-arrest properties of pipeline steel, which increased the high-angle boundary length per unit area and further increased the crack propagation energy during fracture.

A Study of Shear Crack Propagation in Gas-Pressurized Pipelines

1982 ◽  
Vol 104 (4) ◽  
pp. 338-343 ◽  
Author(s):  
E. Sugie ◽  
M. Matsuoka ◽  
T. Akiyama ◽  
H. Mimura ◽  
Y. Kawaguchi
Keyword(s):  
Crack Propagation ◽  
Crack Velocity ◽  
Shear Crack ◽  
Controlled Rolling ◽  
Full Scale ◽  
Pipe Length ◽  
On Line ◽  
Pressurized Pipelines ◽  
Quenching And Tempering ◽  
Crack Propagation And Arrest

Full-scale burst tests were carried out five times on line pipes of 48 in. o.d. × 0.720 in. w.t., Grad. X-70 manufactured by the controlled rolling and the quenching and tempering processes. It was found that the critical notch ductility for arresting a shear crack depends on the pipe length within which the crack is to be arrested. This result is well explained by solving the equation which governs change of crack velocity. The behavior of shear crack propagation and arrest can be well analyzed regardless of the existence or nonexistence of separation by Charpy energy.

scholarly journals Three-Dimensional Simulation of Crack Propagation in the Central-Cracked Flat and Stiffened Plates Under Uniform Tension

2020 ◽  
Author(s):  
Mohammad Hossein Taghizadeh Valdi
Keyword(s):  
Crack Propagation ◽  
Crack Tip ◽  
Crack Arrest ◽  
Correction Function ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
Propagation Behavior ◽  
Out Of Plane ◽  
Plane Bending ◽  
Geometry Correction

Abstract In this paper, the crack propagation behavior in flat and stiffened plates with central-cracked is studied based on the theory of linear elastic fracture mechanics and 3D finite-element method. The magnitude and distribution of the stress intensity factor in a 3D stiffened plates are affected by the out-of-plane bending and loading modes. Initially, for validating this method, the behavior of crack propagation in a central-cracked flat plate (unstiffened), followed by the propagation behavior and the crack arrest effects on stiffened plates by stiffeners, as well as the out-of-plane bending effect on the geometry correction function distribution are studied; However, the results are compared with the results of the referenced article. In order to analyze the effect of stiffeners in preventing crack expansion, stiffeners with variable thickness and height were used. It should also be noted that the crack propagation behavior in the stiffened plate is analyzed in two methods. In the first analysis, after the crack tip reaches to the stiffeners, they have not fracture and the crack only expands in the stiffened plate (in the stiffened plate type 1 and 2). In the second analysis, with the crack growth in the stiffened plate and the crack tip reaching to the stiffeners, Also they fractured and cracks in the stiffened plate and stiffeners are propagated (only in the stiffened plate type 2). In both analyses, the magnitudes ​​of the geometry correction function in the middle-plane, the crack arrest effect by the stiffeners (Δβs), and the out-of-plane bending effect (Δβ) were obtained. Then, the changes in these magnitudes ​​were investigated. It was observed that the stiffeners thickness had a negligible effect on the distribution of the geometry correction function and, in general, the stiffeners had a significant role in preventing the crack growth compared to the flat plate, and the more the crack tip is closer to the adjoining stiffeners; the stiffeners effect in the crack arrest will increases. Furthermore, with attention to the geometry correction function that is studied for different crack sizes, it was determined that the geometry correction function and stress intensity coefficient with increasing the length of the crack in the plate, increase.

Effect of Notch Type in Drop-Weight Tear Test Specimen on Crack Propagation and Arrest Behavior

2018 ◽  
Author(s):  
Satoshi Igi ◽  
Toshihiko Amano ◽  
Takahiro Sakimoto ◽  
Yasuhiro Shinohara ◽  
Tetsuya Tagawa
Keyword(s):  
Crack Propagation ◽  
Large Scale ◽  
Crack Arrest ◽  
Brittle Crack ◽  
Chevron Notch ◽  
Drop Weight ◽  
Drop Weight Tear Test ◽  
Shear Area ◽  
The Impact ◽  
Crack Propagation And Arrest

The drop-weight tear test (DWTT) has been widely used to evaluate the resistance of linepipe steels against brittle fracture propagation. However, in the recent years there is an ambiguity in its evaluation if inverse fracture appears on the specimen fracture surfaces. Although cause of the inverse fracture is not fully understood, compressive pre-straining near the impact hammer and existing tiny split have been discussed as a possible cause. In this paper, machined notch in brittle weld DWTT for X65 was performed and compared with various notch types of DWTTs such as conventional DWTT specimen with a pressed notch (PN), a chevron notch (CN) and a static pre-cracked (SPC). The fracture appearances were compared with different strength X65 - X80 grades linepipes and with different initial notch types. The frequency of the inverse fracture appeared in these DWTTs were different in each material and each specimen types, but there were no cases where the inverse fracture did not occurs. The purpose of DWTT is to evaluate the brittle crack arrestability of the material in a pressurized linepipe. A large scale brittle crack arrest test, so called West Jeferson test is generally used to reproduce crack propagation and arrest behavior in an actual pipeline material. A middle scale test so called Crack Arrest Temperature (CAT) test was also proposed to check the shear area fraction measured in DWTT with API rating with that the local shear lip thickness fraction in those tests. CAT test can well reproduce crack propagation and arrest behavior under the condition of brittle crack initiation from the initial notch.

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