Guided waves scattering by discontinuities near pipe bends

Predoi, Mihai Valentin; Petre, Cristian

doi:10.1121/1.4805575

Cited by 6 publications

(6 citation statements)

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“…Moreover there is a wave focalization on the outer side of the bent, near its middle. This peculiarities have been emphasized for the first time by Predoi and Petre [17], to our knowledge. A decomposition of the plane incident wave into specific toroidal plane waves seems to be not physical.…”

Section: Simulation Resultsmentioning

confidence: 57%

“…In the present research we are focusing on generating a high energy ultrasonic pulse, capable to produce detectable signals from small defects, at relatively high frequency (1MHz). Moreover we discuss the probability of detectability of defects near and especially on pipe bends, continuing previous researches concerning bents [17], by using FEM simulations [18] and optimal selection of modes [19].…”

Section: Introductionmentioning

confidence: 79%

See 1 more Smart Citation

Ultrasonic Guided Waves Inspection of Pipes From One End to the First Bent

Predoi¹,

Soare²,

Vasile³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Non-destructive inspection of long pipes can be time consuming and some localized defects might remain undetected. A new technique based on guided waves was developed in the last decade. High risk industries such as chemical or nuclear, require a reliable method covering if possible the whole length of the piping. Guided ultrasonic waves can propagate along several meters and up to tens of meters in pipes. The reflected signal, which is usually made of some of the propagating modes, brings information concerning the presence of defects and in some conditions on their location and size. There are three classes of guided modes which can propagate in a pipe: longitudinal, torsional and flexural modes. Even if many authors have investigated the guided waves in pipes, in the present research we are focusing on generating a high energy ultrasonic pulse, capable to produce detectable signals from small defects. Moreover we discuss the probability of detectability of defects near and especially on pipe bends. Using our in-house specialized software package to determine the dispersion curves and displacements fields, we determine the incident modes sent in a pipe from its free end, as in heat exchangers. These results are used for optimal numerical simulation, using the Finite Elements Method (FEM), in order to determine the defect detectability. The numerical data are compared with results obtained in laboratory experiments standard equipment for ultrasonic NDT.

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Section: Simulation Resultsmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 79%

Ultrasonic Guided Waves Inspection of Pipes From One End to the First Bent

Predoi¹,

Soare²,

Vasile³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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“…More recently, an analytical modelling approach has been put forward in [138]. Further study on the transmission behaviours of specific modes can be found in [139,140].…”

Section: Pipe Structure: Discontinuity and Bendmentioning

confidence: 99%

A Comprehensive Review of Acoustic Methods for Locating Underground Pipelines

et al. 2020

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Underground pipelines are vital means of transporting fluid resources like water, oil and gas. The process of locating buried pipelines of interest is an essential prerequisite for pipeline maintenance and repair. Acoustic pipe localization methods, as effective trenchless detection techniques, have been implemented in locating underground utilities and shown to be very promising in plastic pipeline localization. This paper presents a comprehensive review of current acoustic methods and recent advances in the localization of buried pipelines. Investigations are conducted from multiple perspectives including the wave propagation mechanism in buried pipe systems, the principles behind each method along with advantages and limitations, representative acoustic locators in commercial markets, the condition of buried pipes, as well as selection of preferred methods for locating pipelines based on the applicability of existing localization techniques. In addition, the key features of each method are summarized and suggestions for future work are proposed. Acoustic methods for locating underground pipelines have proven to be useful and effective supplements to existing localization techniques. It has been highlighted that the ability of acoustic methods to locate non-metallic objects should be of particular practical value. While this paper focuses on a specific application associated with pipeline localization, many acoustic methods are feasible across a wide range of underground infrastructures.

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“…40 Given the above difficulties, detection of defects using L(0,2) and T(0,1) modes near/in elbows circumferentially welded to straight tubes is even more complicated by multiple reflections and mode conversion. 41–44…”

Section: Introductionmentioning

confidence: 99%

Influence of thermal expansion bend and tubesheet geometry on guided wave inspection of steam generator tubes of a fast breeder reactor

Narayanan

Arjun

Kumar

2021

Structural Health Monitoring

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Periodic assessment of steam generator tubes of a sodium-cooled nuclear reactor is very crucial for smooth operation of steam generators. To examine the integrity, an in-bore magnetostrictive transducer capable of launching and receiving longitudinal ultrasonic guided waves (L(0,2) mode) from the inner diameter side of a steam generator tube developed in-house is used. Preliminary tests conducted on defective steam generator tubes with thermal expansion bends (three successive bends) of the mockup steam generator test facility yield a good sensitivity of 20% wall thickness deep flaw (0.46-mm deep and 1-mm wide half-circumferential groove) and the location accuracy of 10 mm. In order to remove high noise, wavelet-based denoising using discrete wavelet transform is used which improves the signal-to-noise ratio by 5–10 dB. In addition, cross-correlation technique is also used to denoise and unambiguously identify the defect echoes amid noise and multiple reflections between the defects. Furthermore, influence of the thermal expansion bend and tubesheet–spigot structure on L(0,2) mode is studied using the finite element analysis. It is observed that in the thermal expansion (multiple) bend, axisymmetric L(0,2) mode becomes non-axisymmetric (maximum and minimum amplitudes at extrados and intrados, respectively) and undergoes mode conversion to a weak flexural mode F(1,3). The results are validated experimentally. In the tubesheet–spigot structure, L(0,2) mode is found to have ∼10% reflection from spigot–tubesheet transitions, and it is seen to mode convert to bulk waves in the tubesheet. In conclusion, thicker tubesheets are found to be better from the perspective of inspection.

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Guided waves scattering by discontinuities near pipe bends

Cited by 6 publications

References 0 publications

Ultrasonic Guided Waves Inspection of Pipes From One End to the First Bent

Ultrasonic Guided Waves Inspection of Pipes From One End to the First Bent

A Comprehensive Review of Acoustic Methods for Locating Underground Pipelines

Influence of thermal expansion bend and tubesheet geometry on guided wave inspection of steam generator tubes of a fast breeder reactor

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