Survey and Tentative Revisal of Ductile Fracture Arrest Prevision Criteria in Pipelines for Gas Transmission

Bonomo, F.; Bramante, M.; Alpa, G.; Bozzo, E.; Morini, A.; Pozzi, A.

doi:10.1007/978-94-009-8594-0_43

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…For steels used in the initial calibration o f the Battelle two-step analysis (as well as the several other empirical models that were subsequently developed by others for applications involving methane based on a comparable fullscale database in the same era (Maxey, 1974;Anon., 1974;Fearnehough and Jones, 1980;V o g tet al, 1983;Bonomo, 1980;Anon, 1983), the fracture resistance measured using a CVN specimen was associated with DDF. Because of their relatively low toughness, the steels o f this era did not show much resistance to the initiation of DDF, nor were there other significant dissipative processes contributing to the apparent DDF resistance.…”

Section: Calibration Of the Battelle "Two-step" Model For Arrest Tougmentioning

confidence: 99%

“…A relationship like Eq. (1) was also developed for the simpler case o f pure or nearly pure methane for use with the simplified form of the Battelle model (Bonomo, 1980). Predictions of the fracture behavior for a given fullscale test or pipeline design relates to the specific temperature involved in that application.…”

Section: Approach To Extend the Validity Of Arrest-prediction Models mentioning

confidence: 99%

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A Numerical Procedure for the Evaluation of the Engine Head-Cylinder Group Cooling Effectiveness

Antonelli

Martorano

Simi

et al. 2009

Volume 2: Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Computational Heat Transfer

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The purpose of this paper is to investigate the thermal flows and heat transfer phenomena occurring in the cooling circuit of a high specific power engine and to suggest a valid method to evaluate its effectiveness in keeping the temperature below a safety limit even in the highest thermal power points. This is a first work showing the analysis of the cooling circuit of a small single-cylinder, four-stroke, high power density gasoline engine carried out with a numerical three-dimensional CFD analysis by means of a CFD conjugate simulation, whose boundary conditions have been taken from a validated one-dimensional fluid dynamic engine model. Once its validity has been assessed by the comparison between the simulation results and data collected by literature and experiments, the interest for this procedure relies on the fact that heat fluxes are directly calculated by the CFD code through the knowledge of gas temperatures and convective heat transfer coefficients. Hence an arbitrary, a priori subdivision of the total heat flux released by fuel combustion into heat converted into mechanical work, heat released to the cooling system, heat rejected to the exhaust, etc. can be avoided; at the same time, the model provides the proper distribution of the heat rejected to the various surfaces constituting the water jackets. The evaluation of the effectiveness of the cooling system is then directly performed in terms of temperature distribution. By this way, once the engine has been designed from a fluid dynamic and mechanical point of view, the effectiveness of the cooling system can be immediately verified through the application of the described procedure. This study takes into consideration the evaluation of average and instantaneous heat transfer coefficient and in-cylinder gas temperature through the use of a validated 1D CFD model, the analysis of the temperature field by means of a conjugate heat transfer simulation of the whole head and cylinder group and an example of the application of this procedure for the evaluation of a simple modification of the cooling system.

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Section: Calibration Of the Battelle "Two-step" Model For Arrest Tougmentioning

confidence: 99%

Section: Approach To Extend the Validity Of Arrest-prediction Models mentioning

confidence: 99%

A Numerical Procedure for the Evaluation of the Engine Head-Cylinder Group Cooling Effectiveness

Antonelli

Martorano

Simi

et al. 2009

Volume 2: Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Computational Heat Transfer

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“…At the same time the specialized model was being developed, researchers in the US and Europe began suggesting other purely empirical models applicable specifically to single-phase decompression. Like the simplified Battelle model, all five empirical expressions that were developed [5][6][7][8][9][10] were calibrated using the CVN test practice. The experiments used to calibrate or validate these early CVN-based models made use of line-pipe steels with toughness typically less than 100 J, consistent with line pipe available in the early 70s.…”

Section: Early Cvn-based Arrest-toughness Modelsmentioning

confidence: 99%

Characterizing Dynamic Crack-Resistance of Pipelines Using Laboratory-Scale Practices

Leis

2000

Volume 1: Codes, Standards and Regulations; Design and Constructions; Environmental; GIS/Database Development; Innovative Proje

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The consequences of a dynamic fracture in a gas-transmission pipeline require that they be designed to avoid such incidents with great certainty. Because of the complexity of this fracture process, the only certain approach to determine fracture-arrest conditions involved full-scale experiments. As time passed empirically calibrated balance equations between the crack-driving conditions and the line-pipe steels crack-arrest capabilities were developed. Such models worked well until the introduction of high-toughness line pipe, for which to full-scale test predictions were non-conservative, and increasingly so as toughness increased. Problems with early CVN-based models led to development of alternative schemes. This paper presents results of experiments done to evaluate plausible alternatives to the CVN practice, which rely on an impact test identical to or adapted from the drop-weight tear-test (DWTT). As this practice is comparable to that of the CVN practice save for using an up-scale specimen geometry, results are presented and contrasted for these test methods, for pipe grades from B to X70, and toughness from less than 10 J in excess of 300 J. Data are analyzed to reveal trends not typically reported for such testing. It is shown that there is no essential difference between data developed from the CVN and DWTT practices, provided the results are compared at similar levels of impact-machine excess-energy capacity. Further, it is shown that non-conservative predictions of full-scale test behavior for higher-toughness steels can be traced to using the early CVN-based models at toughness levels well outside the range of their empirical calibration.

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“…With the aim to identify the resistance force that a pipeline is able to oppose the driving force, given by the pressurized gas, instrumented Drop Weight Tear Tests (DWTs) are performed on SENB-shaped specimens [3][4][5]. The output of these tests are the measurement of the energy lost during the steady state propagation of the crack.…”

Section: Introductionmentioning

confidence: 99%

Effect of fracture tunneling in DWT Tests

Marotta

Minotti

Salvini

2012

Engineering Fracture Mechanics

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a b s t r a c tThe work deals with the effective shape of the fracture during a Drop Weight Tear Test (DWT). An inexpensive technique, able to determine the geometrical shape of the fracture, is discussed and presented. The technique is capable to perform reliable measurements and offers a mathematical description of the fracture profile. In few words, the fracture tunneling measurement and its correlated effects are the objectives of this work. The technique is based on a copy of the fracture by a silicone mold, followed by a digital analysis of the tomographic images. The attention is finally focused on two different steels used in inshore gas piping. The tunneling measurement is exploited in a finite element simulation of the fracture propagation, thus opening the opportunity to update the kinematic models applied for Crack Tip Opening Angle assessment.

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Survey and Tentative Revisal of Ductile Fracture Arrest Prevision Criteria in Pipelines for Gas Transmission

Cited by 5 publications

References 6 publications

A Numerical Procedure for the Evaluation of the Engine Head-Cylinder Group Cooling Effectiveness

A Numerical Procedure for the Evaluation of the Engine Head-Cylinder Group Cooling Effectiveness

Characterizing Dynamic Crack-Resistance of Pipelines Using Laboratory-Scale Practices

Effect of fracture tunneling in DWT Tests

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