Improving laser-EMAT ultrasonic energy conversion efficiency using surface constraint mechanism

Shi, Wei; Tong, Yanshan; Lü, Chao; Chen, Yao; Shen, Gongtian; Zeng, Guangdeng

doi:10.1016/j.ultras.2022.106729

Cited by 11 publications

(2 citation statements)

References 34 publications

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“…Recently, the laser ultrasonic technique (LUT) has been widely exploited for the detection and evaluation of various types of structural damage [21][22][23][24][25][26], due to its superior merits such as the noncontact excitation and wideband reception of ultrasonic waves, high sensitivity to damage and spatial resolution, accessibility to harsh environments and complexed structures. According to numerical and experimental results, multiple types of ultrasonic waves can be generated by a pulsed laser beam, including the skimming longitudinal wave, body longitudinal wave, shear wave, and Rayleigh wave.…”

Section: Introductionmentioning

confidence: 99%

Frequency-dependent Scattering of Wideband Laser-generated Rayleigh Waves for Vertical Surface Crack Characterization

Su²,

Yang³

et al. 2023

Smart Mater. Struct.

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Wideband laser-generated Rayleigh waves have been extensively exploited for surface crack characterization, most of which, nonetheless, are of a nature of either numerical simulation or experimental observation. Earlier, an elastodynamic reciprocity theorem-based theoretical model was proposed by the authors [1, 2], aimed at scrutinizing the interaction of narrowband Rayleigh-Lamb waves with a surface or subsurface crack. In this study, the model is expanded to a wideband scenario to analytically explore the interaction of a wideband laser-generated Rayleigh wave with a surface crack, as well as the resultant crack-scattered Rayleigh wavefield. First, under the narrowband scenario, a dimensionless parameter is formulated based on the closed-form solution to the magnitude of the narrowband scattered Rayleigh wavefield, revealing that the scattering effect of a surface crack on the Rayleigh waves is frequency-dependent and there exists a characteristic frequency, at which the crack-scattered Rayleigh wavefield manifests the strongest intensity. Similarly, under the wideband scenario, such dependence can be calibrated by a spectral damage indicator (SDI), which facilitates the evaluation of the severity of the surface crack using the wideband laser-generated Rayleigh wave. Proof-of-concept simulation is performed to verify the model. Quantitative agreement between the analytical and numerical results validates the accuracy of the proposed model and SDI. Experiment is also conducted to demonstrate the effectiveness of the frequency-dependent scattering of wideband laser-generated Rayleigh waves for vertical surface crack characterization.

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Section: Introductionmentioning

confidence: 99%

Frequency-dependent Scattering of Wideband Laser-generated Rayleigh Waves for Vertical Surface Crack Characterization

Su²,

Yang³

et al. 2023

Smart Mater. Struct.

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“…Furthermore, a prevalent challenge in guided wave inspection methods is the imperative need for signal enhancement to mitigate noise interference and amplify received signal amplitudes. Notably, the presence of substantial noise generated by peripheral machinery necessitates the implementation of effective countermeasures [9][10][11][12][13][14][15]. Moreover, EMAT wave detection currently mainly employs low-frequency regions, and the resolution is relatively low.…”

Section: Introductionmentioning

confidence: 99%

Internal and External Pipe Defect Characterization via High-Frequency Lamb Waves Generated by Unidirectional EMAT

Zhang,

Li,

Zhang

et al. 2023

Sensors

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Periodic permanent magnet(PPM) electromagnetic acoustic transducers (EMATs) are commonly employed for axial defect inspection in pipelines. However, the lowest-order shear horizontal waves (SH0) guided waves have difficulties in distinctly differentiating internal and external defects. To enhance the signal-to-noise ratio and resolution, a unidirectional electromagnetic acoustic transducer (EMAT) based on Circumferential Lamb waves (CLamb waves) is developed. Through structural parameter optimization and excitation frequency adjustment, high-amplitude and low-dispersion CLamb waves are successfully generated in the high-frequency-thickness product region of the dispersion curve. Finite element simulations and experimental validation confirm the capability of this EMAT in exciting CLamb waves for the detection of crack-like defects. Experimental results demonstrate that the excitation efficiency of the CLamb EMAT exceeds that of the periodic permanent magnet electromagnetic acoustic transducer by more than tenfold. The defect reflection signal of the CLamb EMAT exhibits higher resolution and more significant amplitude compared to the PPM EMAT. The integration of this method with SH0 mode detection allows for the inspection of both internal and external defects in pipelines, offering a new avenue for EMAT applications in pipeline inspection.

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Non-contact and non-invasive water level measurement outside metal pipes with electromagnetic acoustic resonance

Shi,

Jin,

Jiang

et al. 2025

Measurement

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Improving laser-EMAT ultrasonic energy conversion efficiency using surface constraint mechanism

Cited by 11 publications

References 34 publications

Frequency-dependent Scattering of Wideband Laser-generated Rayleigh Waves for Vertical Surface Crack Characterization

Frequency-dependent Scattering of Wideband Laser-generated Rayleigh Waves for Vertical Surface Crack Characterization

Internal and External Pipe Defect Characterization via High-Frequency Lamb Waves Generated by Unidirectional EMAT

Non-contact and non-invasive water level measurement outside metal pipes with electromagnetic acoustic resonance

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