The sensitivity of failure analysis of boiler tubes to the shape of elliptical external erosion flaws

Kalu, Ifeanyi Emmanuel; Inglis, Helen M.; Kok, Schalk

doi:10.1016/j.engfailanal.2020.104952

Cited by 3 publications

(1 citation statement)

References 30 publications

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“…Based on the magnetic dipole model of rectangular and cylindrical crack defects, this paper obtains the integral expression of the leakage magnetic defect signals of conical holes, elliptical holes, hyperbolic crack holes, and truncated cone holes, and verifies the rationality of the expression through experiments, providing a new method for quantitatively analyzing the variation in leakage magnetic signals on the surface of defects. At the same time, it also provides a new analysis method for difficult-to-detect locations and regions, such as stress corrosion defects with elliptical shapes in boilers and saddle-shaped defects in reactor pressure vessels [ 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Charge Model for Leakage Signals from Surface Defects in Ferromagnetic Material

Sheng

Zhang

et al. 2023

Materials

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A novel three-dimensional theoretical model of magnetic flux leakage (MFL) is proposed in this paper based on the magnetic dipole model. The magnetic dipole model assumes that a ferromagnetic specimen with defects is exposed to a uniform external magnetic field that causes a uniform magnetization around the defect surface. Under this assumption, the MFL can be regarded as arising from magnetic charges on the defect surface. Previous theoretical models were mostly used to analyze simple crack defects such as cylindrical and rectangular cracks. In this paper, we developed a magnetic dipole model for more complex defect shapes such as circular truncated holes, conical holes, elliptical holes, and double-curve-shaped crack holes to complement the existing defect shapes. Experimental results and comparisons with previous models demonstrate that the proposed model provides a better approximation of complex defect shapes.

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Section: Introductionmentioning

confidence: 99%

Magnetic Charge Model for Leakage Signals from Surface Defects in Ferromagnetic Material

Sheng

Zhang

et al. 2023

Materials

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Failure in power plant system related to mitigations and economic analysis; A study case from steam power plant in Suralaya, Indonesia

Nugraha¹,

Harianto²,

Muflikhun

2023

Results in Engineering

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Prediction of the Time to Failure of Boiler Tubes Flawed With Localized Erosion

Kalu

Inglis

Kok

2023

Journal of Pressure Vessel Technology

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A failure mechanism prevalent with boiler tubes operating in harsh environmental conditions is localized erosion. The consequence of the erosion mechanism is a substantial reduction of the tube thickness, ultimately leading to plastic collapse and consequently rupturing of the tubes. Locating and repairing all the affected tubes within the boiler is time consuming and expensive. It will be worthwhile to rank all the identified flaws so that critical flaws that cannot survive till the next scheduled shutdown are prioritized for repair. Consequently, nonlinear structural analysis was conducted on various boiler tubes that failed by localized erosion. The tubes had a wide range of localized erosion flaws that required a detailed assessment technique. The failure was evaluated numerically using various stress and strain-based failure criteria as well as performing the American Petroleum Institute and the American Society of Mechanical Engineers (API-ASME) fitness-for-service (FFS) assessment on the tubes. A projected time to failure ( P_t) for each tube based on the various criteria used in this study was determined. This enabled the ranking of the flawed tubes based on the priority of their repair. The outcome of this study demonstrates the potential for a tool which will enable industry users to prioritise the replacement or repair of critically flawed tubes and avert replacing tubes that are still safe for future operation.

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The sensitivity of failure analysis of boiler tubes to the shape of elliptical external erosion flaws

Cited by 3 publications

References 30 publications

Magnetic Charge Model for Leakage Signals from Surface Defects in Ferromagnetic Material

Magnetic Charge Model for Leakage Signals from Surface Defects in Ferromagnetic Material

Failure in power plant system related to mitigations and economic analysis; A study case from steam power plant in Suralaya, Indonesia

Prediction of the Time to Failure of Boiler Tubes Flawed With Localized Erosion

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