Evaluation of limit load data for cracked pipe bends under opening bending and comparisons with existing solutions

Yahiaoui, K.; Moreton, D. N.; Moffat, D. G.

doi:10.1016/s0308-0161(01)00131-4

Cited by 44 publications

(30 citation statements)

References 11 publications

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“…Their condition, before and after the deformation of the specimen, is recorded through their four fringe images which are taken before and after their deformation by an external force [6,8]. The intensity of light, before the object is deformed by the force, is given as follows:…”

Section: Theorymentioning

confidence: 99%

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Optical-fiber Electronic Speckle Pattern Interferometry for Quantitative Measurement of Defects on Aluminum Liners in Composite Pressure Vessels

Kim¹,

Kang²,

Choi³

2013

Journal of the Optical Society of Korea

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Optical-fiber electronic speckle pattern interferometry (ESPI) is a non-contact, non-destructive examination technique with the advantages of rapid measurement, high accuracy, and full-field measurement. The optical-fiber ESPI system used in this study was compact and portable with the advantages of easy set-up and signal acquisition. By suitably configuring the optical-fiber ESPI system, producing an image signal in a charge-coupled device camera, and periodically modulating beam phases, we obtained phase information from the speckle pattern using a four-step phase shifting algorithm. Moreover, we compared the actual defect size with that of interference fringes which appeared on a screen after calculating the pixel value according to the distance between the object and the CCD camera. Conventional methods of measuring defects are time-consuming and resource-intensive because the estimated values are relative. However, our simple method could quantitatively estimate the defect length by carrying out numerical analysis for obtaining values on the X-axis in a line profile. The results showed reliable values for average error rates and a decrease in the error rate with increasing defect length or pressure.

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Section: Theorymentioning

confidence: 99%

“… O , and  R are the phases of the object and reference light beams, respectively [7,8]. When the object is deformed by the external force, the intensity of light is expressed as follows:…”

Section: Theorymentioning

confidence: 99%

Optical-fiber Electronic Speckle Pattern Interferometry for Quantitative Measurement of Defects on Aluminum Liners in Composite Pressure Vessels

Kim¹,

Kang²,

Choi³

2013

Journal of the Optical Society of Korea

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“…Even for cracked pipes, analytical, experimental and finite element (FE) solutions have been well documented [8,9,10]. For pipe bends without defects or with crack defects, some limit load solutions are available in the literature [11][12][13][14][15][16]. Compared to those of straight pipes, plastic limit analysis of pipe bends are complicated not only due to more geometric variables involved, such as the bend radius and angle, but also due to the large geometry change effect [17].…”

Section: Introductionmentioning

confidence: 99%

“…Compared with fracture analysis, plastic limit load analysis can be economically acquired and provide great convenience to engineers. In addition, failure of piping components with highly ductile materials and often used in elevated temperature pressure circuits is frequently dominated by plastic collapse [13]. It is especially important for nuclear power plants because of the application of leak-before-break (LBB) concept which involves detailed integrity assessment of primary heat transport piping systems taking into account the postulated cracks [23,24].…”

Section: Introductionmentioning

confidence: 99%

Plastic limit loads for pipe bends with circumferential through-wall crack under torsion moment

Zhou

Miao

et al. 2015

International Journal of Mechanical Sciences

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“…Earlier limit load solutions for pipe bends were based either on empirical ones using experimental data (Greenstreet 1978;Griffiths 1979) or on analytical ones (Spence and Findlay 1973;Calladine 1974;Goodall 1978), as summarized in Miller (1986Miller ( , 1988). More recently, although some experimental works have been done (Yahiaoui et al 2002;Chattopahyay et al 2004a), numerical analyses using finite element (FE) methods are increasingly popular Younan 1998, 1999;Chattopadhyay et al 2000Chattopadhyay et al , 2004bRobertson et al 2005;Yahiaoui et al 2000;Oh 2006a, b, 2007). For 90 • pipe bends under combined pressure and in-plane bending, Kim and Oh (2006a) performed extensive geometrically linear FE analyses using elastic-perfectly plastic materials, and found that published analytical solutions (Spence and Findlay 1973;Calladine 1974;Goodall 1978) were much lower than FE results.…”

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confidence: 99%

Plastic loads of pipe bends under combined pressure and out-of-plane bending

Lee¹,

Kim²,

Park

2008

Int J Fract

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This paper provides plastic limit and TES (twice-elastic-slope) plastic load solutions for 90 • pipe bends under combined pressure and out-of-plane bending, via threedimensional non-linear FE analyses using elastic-perfectly plastic materials. Without internal pressure, a closed-form approximation is given. For combined pressure and out-of-plane bending, tabulated data are given, from which TES plastic loads can be interpolated. It is found that TES plastic loads for pipe bends under out-of-plane bending are lower than those under in-plane opening bending, but are higher than those under in-plane closing bending. It suggests that the in-plane closing bending mode is the most critical loading mode for 90 • pipe bends, which is fully consistent to existing findings.Keywords Combined pressure and out-of-plane bending · Finite element limit analysis · Pipe Bend · Twice-elastic-slope plastic load Nomenclature E Young's modulus M Out-of-plane bending moment M o TES plastic out-of-plane moments of pipe bends P Internal pressure P o Limit pressure of a pipe bend P s o Limit pressure of a straight pipe = 2 √ 3 σ o t r R Bend radius r Mean pipe radius t Thickness of pipe

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Evaluation of limit load data for cracked pipe bends under opening bending and comparisons with existing solutions

Cited by 44 publications

References 11 publications

Optical-fiber Electronic Speckle Pattern Interferometry for Quantitative Measurement of Defects on Aluminum Liners in Composite Pressure Vessels

Optical-fiber Electronic Speckle Pattern Interferometry for Quantitative Measurement of Defects on Aluminum Liners in Composite Pressure Vessels

Plastic limit loads for pipe bends with circumferential through-wall crack under torsion moment

Plastic loads of pipe bends under combined pressure and out-of-plane bending

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