Dispersion and attenuation by transmission, reflection, and mode conversion in welded pipes

Vogelaar, Bbsa; Golombok, M Michael

doi:10.1016/j.apacoust.2016.03.007

Cited by 7 publications

(13 citation statements)

References 29 publications

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“…For example, the method has been demonstrated to work in welded joint pipes. 3 Liquid contents are not a problem and indeed the attenuation is less when the inner and outer fluids are the same, 4 and this presents some advantages for the application of acoustic testing in pipelines compared to the standard methods which are restricted to above ground. 5 Moreover, pipe bends do not constitute a problem provided these are not too tight.…”

Section: Introductionmentioning

confidence: 99%

Time-lapse acoustic monitoring of deteriorating pipes

Vogelaar

Priems

Bourgonje

et al. 2018

Structural Health Monitoring

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In-service degradation of a pipe section is monitored in real time with torsional guided waves which can resolve 5% damage to the internal wall. We use a single permanently installed source–receiver pair as opposed to the current state-of-the-art sensor rings. There is no baseline subtraction requirement as a single reflection coefficient is derived by internal referencing of the time trace. Even with continuously operating pump vibration, there is enough acoustic signal for confident damage localization. Since pipelines wear out gradually in industrial installations, the acoustic footprint is similar to that previously determined in periodically damaged pipes. The reflective method can thus be applied successfully to monitor structural health in industrial pipelines during operation as opposed to the current state-of-the-art guided wave inspection approaches using near-weld reflection techniques along with disassembled and re-assembled sensor rings.

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Section: Introductionmentioning

confidence: 99%

Time-lapse acoustic monitoring of deteriorating pipes

Vogelaar

Priems

Bourgonje

et al. 2018

Structural Health Monitoring

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“…Ultrasonic guided wave is an effective nondestructive testing (NDT) tool for checking the normality of these structures and detecting probable defects caused by corrosion or other environmental elements [ 1 , 2 , 3 , 4 , 5 ]. Dispersion, multiple modes, and noise are common problems associated with using guided waves [ 6 , 7 , 8 , 9 , 10 ]. As guided wave propagates, dispersion makes its energy spread out in space and time.…”

Section: Introductionmentioning

confidence: 99%

Sparse and Dispersion-Based Matching Pursuit for Minimizing the Dispersion Effect Occurring when Using Guided Wave for Pipe Inspection

2017

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Ultrasonic guided wave is an effective tool for structural health monitoring of structures for detecting defects. In practice, guided wave signals are dispersive and contain multiple modes and noise. In the presence of overlapped wave-packets/modes and noise together with dispersion, extracting meaningful information from these signals is a challenging task. Handling such challenge requires an advanced signal processing tool. The aim of this study is to develop an effective and robust signal processing tool to deal with the complexity of guided wave signals for non-destructive testing (NDT) purpose. To achieve this goal, Sparse Representation with Dispersion Based Matching Pursuit (SDMP) is proposed. Addressing the three abovementioned facts that complicate signal interpretation, SDMP separates overlapped modes and demonstrates good performance against noise with maximum sparsity. With the dispersion taken into account, an overc-omplete and redundant dictionary of basic atoms based on a narrowband excitation signal is designed. As Finite Element Method (FEM) was used to predict the form of wave packets propagating along structures, these atoms have the maximum resemblance with real guided wave signals. SDMP operates in two stages. In the first stage, similar to Matching Pursuit (MP), the approximation improves by adding, a single atom to the solution set at each iteration. However, atom selection criterion of SDMP utilizes the time localization of guided wave reflections that makes a portion of overlapped wave-packets to be composed mainly of a single echo. In the second stage of the algorithm, the selected atoms that have frequency inconsistency with the excitation signal are discarded. This increases the sparsity of the final representation. Meanwhile, leading to accurate approximation, as discarded atoms are not representing guided wave reflections, it simplifies extracting physical meanings for defect detection purpose. To verify the effectiveness of SDMP for damage detection results from numerical simulations and experiments on steel pipes are presented.

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“…Whereas R dam was insensitive to the medium, R dam 'is more sensitive than R dam for a liquid filled pipe. The fits shown are trend lines: the relatively large amount of scatter derives from the fact that although severely dampened there are residual modes still present in our signal as we have previously shown [13][14][15]. R dam ' displays much more scatter than R dam .…”

Section: Damage Detectionmentioning

confidence: 99%

“…This is related to the difference in resistance to shear at the inner and outer boundary of the thin wall. Different fluids at the inner and outer wall yield a stress gradient in the (membrane-like) wall, leading to the wave generation of flexural modes [13][14][15]. These fluidinduced vibrations add to the apparent high shear damping for different inner/outer fluids in flexible structures, such as our thin-walled pipe.…”

Section: Medium Effectsmentioning

confidence: 99%

“…Each collar contains up to 16 signal sensors. We have shown that this can be reduced by >90% and also made to work over a much longer pipe length [13][14][15] thus simplifying the overal configuration of such a detection system. This used the simplest acoustic mode, the so-called T(0,1) which has been shown to predominate in pipe transmission and to be dispersion free.…”

Section: Introductionmentioning

confidence: 99%

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Simplified Ultrasonic Damage Detection in Fluid-Filled Pipes

Vogelaar

Golombok

2017

J Nondestruct Eval

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The location and extent of damage in a pipe can be remotely determined from weld and internal damage reflections using a single acoustic emitter/sensor pair. The use of normalised reflections yields single numbers enabling long distance data collection techniques such as wireless hopping. The attenuation is twice as high for opposite inner and outer fluids (whether air and water, or water and air) as compared to identical inner and outer fluids. The absolute recorded signals in the water-filled pipe are attenuated by a factor two compared to the empty pipe. The axial length of detection is reduced by a half. The reduction of >90% in sensors and the longer axial detection (>10× current state-of-theart-technology) means that permanent fixed sensor pairs for whole pipelines are on the horizon of possibility. The greatest advantage is envisioned in submersed pipelines.

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Dispersion and attenuation by transmission, reflection, and mode conversion in welded pipes

Cited by 7 publications

References 29 publications

Time-lapse acoustic monitoring of deteriorating pipes

Time-lapse acoustic monitoring of deteriorating pipes

Sparse and Dispersion-Based Matching Pursuit for Minimizing the Dispersion Effect Occurring when Using Guided Wave for Pipe Inspection

Simplified Ultrasonic Damage Detection in Fluid-Filled Pipes

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