Guided waves in a plate with linearly varying thickness: experimental and numerical results

Elkettani, Mounsif Echcherif; Luppé, Francine; Guillet, Arnaud

doi:10.1016/j.ultras.2004.01.071

Cited by 45 publications

(21 citation statements)

References 5 publications

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“…It has been shown that such structural details do not fundamentally affect the propagation of FFGW and that models based on simplified plate (2D) or tube (3D) geometry provide good predictions on FFGW in real bone (Moilanen et al, 2007b;Moilanen et al, 2007c). Tapering of layers or of the entire bilayer system is, on the other hand, known to alter the mode map (Ech-Cherif El-Kettani et al, 2004). In this case, modes other than FFGW are mainly affected.…”

Section: G Limitations Of the Studymentioning

confidence: 99%

Tailoring the excitation of fundamental flexural guide waves in coated bone by phase-delayed array: Two-dimensional simulations

Kilappa

Moilanen

Salmi

et al. 2015

The Journal of the Acoustical Society of America

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The fundamental flexural guided wave (FFGW) enables ultrasonic assessment of cortical bone thickness. In vivo, it is challenging to detect this mode, as its power ratio with respect to disturbing ultrasound is reduced by soft tissue covering the bone. A phase-delayed ultrasound source is proposed to tailor the FFGW excitation in order to improve its power ratio. This situation is analyzed by 2D finite-element simulations. The soft tissue coating (7-mm thick) was simulated as a fluid covering an elastic plate (bone, 2-6 mm thick). A six-element array of emitters on top of the coating was excited by 50-kHz tone bursts so that each emitter was appropriately delayed from the previous one. Response was recorded by an array of receivers on top of the coating, 20-50 mm away from the closest emitter. Simulations predicted that such tailored/phase-delayed excitations should improve the power ratio of FFGW by 23 ± 5 dB, independent of the number of emitters (N). On the other hand, the FFGW magnitude should increase by 5.8 ± 0.5 dB for each doubling of N. This suggests that mode tailoring based on phase-delayed excitation may play a key role in the development of an in vivo FFGW assessment.

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Section: G Limitations Of the Studymentioning

confidence: 99%

Tailoring the excitation of fundamental flexural guide waves in coated bone by phase-delayed array: Two-dimensional simulations

Kilappa

Moilanen

Salmi

et al. 2015

The Journal of the Acoustical Society of America

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“…The usual approach in this case is to consider the lowest modes of a Lamb wave, including symmetric and anti-symmetric modes in a plate whose thickness varies slowly with distance so that at any point, the Lamb wave analysis for constant thickness can be applied (these propagating waves in a slowly varying cross-sectional area are adiabatic waves where the wave continuously adapts to the change in local thickness through a modification of the wavenumber and phase velocity) 18 …”

mentioning

confidence: 99%

Point mobility of a cylindrical plate incorporating a tapered hole of power-law profile

O'Boy

Bowyer

Krylov

2011

The Journal of the Acoustical Society of America

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“…(1) is acceptable for the computation of its group delay. [11][12][13] Obviously, this requires that the GW considered in each segment for the computation of the group delay is generated by the incoming wave that has been considered in the previous segment of waveguide.…”

Section: Group Delay Computationmentioning

confidence: 99%

Localization of defects in irregular waveguides by dispersion compensation and pulse compression

et al. 2013

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In this work a pulse-echo procedure suitable to locate defect-induced reflections in irregular waveguides is proposed. In particular, the procedure extracts the distance of propagation of a guided wave scattered from a defect within the echo signal, revealing thus the source-defect distance. To such purpose, first, a Warped Frequency Transform (WFT) is used to compensate the signal from the dispersion of the guided wave due to the traveled distance in a portion of the waveguide that is assumed as reference. Next, a pulse compression procedure is applied to remove the additional dispersion introduced by the remaining irregular portion of the waveguide.Thanks to this processing the actual distance traveled by the wave in the regular portion of the irregular waveguide is revealed. Thus the proposed strategy extends pulse-echo defect localization procedures based on guided waves to irregular waveguides. Since the processing is based on Fast Fourier Transforms, the algorithm can be easily implemented in real time applications for structural health monitoring. The potential of the procedure is numerically demonstrated by processing Lamb waves propagating in an irregular waveguide composed by aluminum plates with different thicknesses and tapered portions.

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Guided waves in a plate with linearly varying thickness: experimental and numerical results

Cited by 45 publications

References 5 publications

Tailoring the excitation of fundamental flexural guide waves in coated bone by phase-delayed array: Two-dimensional simulations

Tailoring the excitation of fundamental flexural guide waves in coated bone by phase-delayed array: Two-dimensional simulations

Point mobility of a cylindrical plate incorporating a tapered hole of power-law profile

Localization of defects in irregular waveguides by dispersion compensation and pulse compression

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