Superposition model of mode shapes composed of travelling torsional guided waves excited by multiple circular transducer arrays in pipes

Niu, Xinli; Tee, Kong Fah; Marques, Hugo

doi:10.1016/j.ultras.2021.106507

Cited by 16 publications

(4 citation statements)

References 18 publications

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“…Because of the good performance of the transducer, it has been applied for studying different types of crack reflections [64][65][66], coating layer reflections [67,68], crack-like defect imaging [69] and chemical plant pipeline inspection [70,71]. To optimise the signal-to-noise ratio of the in-plane poled thickness-shear d 15 mode piezoelectric, Niu et al [72,73] superimposed multiple ring transducers. Boivin et al [74] found that the unwanted mode can be restrained by increasing the transducer length.…”

Section: Piezoelectric Torsional Transducer Arraymentioning

confidence: 99%

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

Fang

2023

Smart Mater. Struct.

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An axisymmetric guided wave mode is excited independently within a circular tube structure to reduce the complexity of signal interpretation through the prevention of unwanted wave polarisations and reflections. However, it is difficult to use the axisymmetric guided wave to determine the circumferential position and coverage of a defect within the circular tube structure. Non-axisymmetric guided waves can be used to mitigate the limitation of the axisymmetric guided wave through the adoption of a partially covered transducer design and analysis of the propagation characteristics. The partial excitation of non-axisymmetric guided waves can facilitate the arrangement of a transducer during defect detection. This paper reviews state-of-the-art research on non-axisymmetric guided waves for determining the axial positions, circumferential positions, and circumferential lengths of defects. First, the fundamental analysis of a specific non-axisymmetric guided wave mode based on the normal mode expansion method and beam directivity analysis method reveals that the propagation characteristics of the wave mode are closely related to the working principle and configuration of the corresponding transducer. Then, the advantages and disadvantages of the different types of transducers and transducer arrays for the excitation of non-axisymmetric guided waves are introduced and discussed. Finally, the current defect detection methods based on non-axisymmetric guided waves are discussed and summarised. This review can promote the application of non-axisymmetric guided waves in defect detection.

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Section: Piezoelectric Torsional Transducer Arraymentioning

confidence: 99%

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

Fang

2023

Smart Mater. Struct.

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“…Sixteen PZT transducers were coupled at both ends of grouted sleeves in the form of a circular array. Among the other types of PZT arrays (parallel, rectangular, and cross configurations), ring arrays are the most preferred for applications in cylindrical structures, such as tubes [43,44]. The schematic of PZTs is presented in figure 4.…”

Section: Specimen Designmentioning

confidence: 99%

Combined two-level guided wave structural health monitoring strategy using multifeature integration and machine learning: application to early-age grouted sleeves

Liu,

Yi,

et al. 2023

Smart Mater. Struct.

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Structural health monitoring of grouted sleeves is one of the assembly industry’s huge challenges. In this study, a combined two-level damage detection was introduced. It comprises defect classification (healthy, rebar eccentricity, and grout leakage) and severity evaluation for early-age grouted sleeves using guided waves. Multiple features (MF) from time-, frequency-, and time-frequency domains were extracted and defined according to the diverse defects and ages of grouted sleeves to represent complex damage characteristics. Moreover, the egret swarm algorithm optimization–extreme learning machine (ESAO-ELM) models were proposed to avoid the influence of subjective experience and judgment from experts. ESAO optimized the initial random parameters (input weights and hidden layer bias) of ELM. Then, two MF-ESAO-ELM models were trained for two-level damage detection on the experimental dataset. The performance of the proposed models was comprehensively evaluated using accuracy, recall, precision, and confusion matrix. MF-ESAO-ELM performs better than ELM and PSO-ELM in accuracy. In this strategy, the defect classification model works in the outer layer to distinguish the state and types of defects of grouted sleeves (healthy, eccentric, or leakage). In comparison, the inner layer starts predicting the severity only if the defect type is leakage. MF-ESAO-ELM offers advantages in terms of accuracy, strategy, and calculation time.

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“…The reason of that the higher order wave modes appearance as a coherent noise level leads to the non-dispersed travelling wavefield propagated with following some dispersive waves. The influenced effect for the PSL SNR could be more obvious when the echo signal is received from a longer distance at the operating frequency of 40 kHz (see Figure 10b) The relevant research and improvements were investigated in [23,28].…”

Section: Excitation Sequence Characteristicsmentioning

confidence: 99%

Hybrid Coded Excitation of the Torsional Guided Wave Mode T(0,1) for Oil and Gas Pipeline Inspection

et al. 2022

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Ultrasonic guided wave testing is an essential technique in non-destructive testing for structural integrity of oil and gas pipelines. This technique, based on the pulse-echo method, is often used for the long-range detection of pipelines at any location. However, guided waves suffer from high attenuation when they propagate in attenuative material structures and multiple wave modes due to the excitation, which reduces the power of echo signals and induces corruption caused by coherent noise. In this paper, a developed hybrid coded excitation method that uses the convolution of a Barker code and Golay code pair is proposed and applied for an ultrasonic guided wave testing system to excite the torsional guided wave mode T(0,1) in a steel pipe. The proposed method combines the advantages of these two coding methods and increases the flexibility of code lengths. The performance is evaluated by signal to noise ratio and peak sidelobe level of the processed signal. Both theoretical simulations and experiments have investigated using the proposed codes composed of Barker codes and Golay code pairs of different lengths and combinations. The experimental results show the significant improvement of the signal to noise ratio and the peak sidelobe level due to the proposed hybrid code usage for the excitation of guided waves. The values are further improved to around 32 dB and around −24 dB, respectively. Overall, the proposed hybrid coded method for improving the echo SNR can benefit from guided wave testing to reduce coherent and random noise levels and many other potential applications.

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Superposition model of mode shapes composed of travelling torsional guided waves excited by multiple circular transducer arrays in pipes

Cited by 16 publications

References 18 publications

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

Combined two-level guided wave structural health monitoring strategy using multifeature integration and machine learning: application to early-age grouted sleeves

Hybrid Coded Excitation of the Torsional Guided Wave Mode T(0,1) for Oil and Gas Pipeline Inspection

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