Study of guided wave propagation on a plate between two solid bodies with imperfect contact conditions

Balvantín, Antonio J.; Peña, José Ángel; Leyva, Pablo Alberto Limon; Hernández-Rodríguez, E.

doi:10.1016/j.ultras.2017.06.003

Cited by 13 publications

(5 citation statements)

References 28 publications

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“…There are many studies on the improvement of the transduction efficiency of body waves and surface waves, but there are not many studies on the improvement of the transduction efficiency of single-mode Lamb wave transducers and structural modifications. Only the lowest order S 0 waves and A 0 waves can be excited at any frequency in each set of Lamb waves [19][20][21]. At the low frequency-thickness product ( f • d), the S 0 wave propagates with less dispersion and is therefore more suitable for measuring the elastic characteristics of thin plates or detecting their possible defects [22,23].…”

Section: Introductionmentioning

confidence: 99%

An EMAT for improving the purity and amplitude of S₀ Lamb waves

Yang

Zhang²,

Wu³

et al. 2022

Meas. Sci. Technol.

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Different waves of the Lamb waves may be superimposed in practical tests due to its multimodal characteristics and dispersion characteristics, thus greatly increasing the difficulty of later signal analysis and creating a huge limitation to their application in non-destructive testing (NDT). Only a single magnet was used to generate a static magnetic field in the traditional S0 mode Lamb wave (S0 wave) electromagnetic acoustic transducer (EMAT), which resulted in a less pure S0 wave. Additionally, the accompanying A0 mode Lamb wave (A0 wave) will decrease the accuracy of the results in defect detection and increase the difficulty of the signal processing. In order to obtain a single-mode S0 wave, a periodic magnet structure EMAT structure was proposed in this study. Finite element models were established and the effect of single and periodic magnet structure on the static magnetic field was analyzed. The periodic magnet structure EMAT can substantially enhance the S0 mode Lamb wave amplitude by increasing the flux density of the local magnetic field using periodically arranged magnets. However, it also causes enhancement to the A0 wave and decreases the detection accuracy. An improved EMAT was further proposed to increase the S0 wave amplitude with no enhancement to the A0 wave amplitude. Experiments were conducted and two types of EMAT were comparatively investigated, which agreed with the simulated results. The S0 wave amplitude can be increased by 7 times with the improved EMAT compared to traditional EMAT, and the A0 wave is completely submerged in the noise. The improved EMAT proposed in this study can provide guidance for the single-mode S0 wave defect detection.

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Section: Introductionmentioning

confidence: 99%

An EMAT for improving the purity and amplitude of S₀ Lamb waves

Yang

Zhang²,

Wu³

et al. 2022

Meas. Sci. Technol.

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“…20 whereF {•} and F −1 {•} are the operators of the forward and inverse Fourier transform, respectively, i is the imaginary symbol, and c p (f ) is the phase velocity of the Lamb wave mode computed by using the Rayleigh-Lamb equation. 21 The expression d = (x − x 0 ) 2 + (y − y 0 ) 2 represents the distance between the location (x, y) and emitting source coordinate (x 0 , y 0 ).…”

Section: Topological Imaging Theorymentioning

confidence: 99%

Lamb Waves Topological Imaging of Multiple Blind Defects in an Isotropic Plate

Zhu¹,

Zhang²,

Xu³

et al. 2019

The International Journal of Acoustics and Vibration

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The study investigates the feasibility of the Lamb wave topological imaging method for detecting multiple blindholes in an isotropic plate. The topological imaging method is performed based on the computations of two wave fields, a forward and an adjoint, in the defect-free reference medium using different emitting sources. The image is computed by multiplying the forward and adjoint wave fields together and integrating them over time or frequency. The interferences of multimode aliasing and the scattering effect can thus be eliminated at the defectfree positions with an improved image resolution. To investigate the physical mechanism, the refocusing process of the multimode Lamb waves at the defect positions is presented by a face-to-face comparison between the snapshots of the forward and adjoint wave fields using the finite element simulation. The Lamb wave topological imaging method is numerically and experimentally verified to identify multiple blind-holes in an isotropic aluminium plate. The results demonstrate that the topological imaging method enables the suppression of the sartefacts resulting from the mode conversion and achieve high-resolution imaging of the blind defects

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“…Although the solution accuracy improves with a smaller value of the time step and element size, unnecessarily small values necessitate significantly increased computational time. For these reasons, it is generally recommended to use 8 to 20 elements per wavelength [13,18,19], and 10 to 20 points per cycle of the highest frequency for the time step [13,20]. In this study, the time step and the element size were evaluated using Equations (6) and (7).…”

Section: Transient Simulationsmentioning

confidence: 99%

Quantification of Bolt Tension by Surface Acoustic Waves: An Experimentally Verified Simulation Study

Alhazmi

Guldiken

2019

Acoustics

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Quantifying bolt tension and ensuring that bolts are appropriately tightened for large-scale civil infrastructures are crucial. This study investigated the feasibility of employing the surface acoustic wave (SAW) for quantifying the bolt tension via finite element modeling. The central hypothesis is that the real area of contact in a bolted joint increases as the tension or preload is increased, causing an acoustical signature change. The experimentally verified 3-D simulations were carried out in two steps: A preload was first applied to the bolt body to simulate the realistic behavior of bolted joint; and the SAW propagation was then excited on the top surface of the plate to reflect from the bolted joint. The bolt tension value was varied between 4 and 24 kN (properly tightened bolt) in the steps of 4 kN to study the effect of the bolt tension. The results indicate an increased reflected wave amplitude and a gradual phase shift, up to 0.5 µs, as the bolt tension increased. Furthermore, the result shows that the distance between the first reflected wave and the source becomes shorter as the preload increases, as hypothesized. A 1.9 mm difference in the distance between the maximum and minimum preload was observed. As part of this study, the simulation results were also compared with the experimental results, and a good agreement between the simulation and experiments was demonstrated.

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Study of guided wave propagation on a plate between two solid bodies with imperfect contact conditions

Cited by 13 publications

References 28 publications

An EMAT for improving the purity and amplitude of S₀ Lamb waves

An EMAT for improving the purity and amplitude of S₀ Lamb waves

Lamb Waves Topological Imaging of Multiple Blind Defects in an Isotropic Plate

Quantification of Bolt Tension by Surface Acoustic Waves: An Experimentally Verified Simulation Study

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Study of guided wave propagation on a plate between two solid bodies with imperfect contact conditions

Cited by 13 publications

References 28 publications

An EMAT for improving the purity and amplitude of S0 Lamb waves

An EMAT for improving the purity and amplitude of S0 Lamb waves

Lamb Waves Topological Imaging of Multiple Blind Defects in an Isotropic Plate

Quantification of Bolt Tension by Surface Acoustic Waves: An Experimentally Verified Simulation Study

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Product

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An EMAT for improving the purity and amplitude of S₀ Lamb waves

An EMAT for improving the purity and amplitude of S₀ Lamb waves