Interaction of lamb modes with delaminations in plates coated by highly absorbing materials

Shkerdin, G. N.; Glorieux, Christ

doi:10.1109/tuffc.2007.250

Cited by 11 publications

(3 citation statements)

References 21 publications

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“…It is obvious that for the numerical evaluation it is necessary to truncate this system to a finite number of local modes. The calculation accuracy could be also quantified by the relative errors of EM energy flow conservation at the interface planes z=(0, L z ) [24]; however, the condition of boundary equations (4a)-(4d) fulfilment is a more general one and this condition leads automatically to EM energy flow conservation fulfilment. It is also important to remark that the EM energy flow is mainly transferred by propagating modes (in the nonabsorptive case even only by propagating modes).…”

Section: Modal Decomposition Methods In a Rectangular Metal Waveguide...mentioning

confidence: 99%

Modulation of TE propagation modes in rectangular metal waveguide with integrated graphene structure in the sub-terahertz frequency range

Shkerdin

Alkorre

et al. 2016

J. Opt.

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The propagation of TE modes in a rectangular metal waveguide with an integrated structure of finite length containing a graphene monolayer was studied by a modal decomposition method. The modal decomposition method generates a number of linear algebraic equations related to waveguide modes taken into account. The system of linear algebraic equations for the amplitudes of all modes was derived taking into account the propagation as well as a number of local evanescent modes. Truncation errors in the function of the number of modes taken were quantified by using the discontinuities of the boundary conditions for the transverse electric and magnetic field components at the interface of the discontinuities of the structure. The transmitted and reflected TE01 mode amplitudes were calculated versus the graphene layer length, its position inside the waveguide cavity and the graphene electrons chemical potential. It was shown that the symmetrical positioning of the graphene layer inside the waveguide cavity is the most suitable to achieve the largest amplitude modulation, whereas an asymmetrical positioning is suitable to achieve a large phase modulation of the transmitted mode. It was shown that the phase modulation increases with a transmission coefficient modulation increase and decreases with a transmission coefficient increase. It was found that the phase modulation firstly increases almost proportionally with the graphene layer length for relatively short structures; however, after passing through a maximum, the phase modulation becomes almost constant and hence only weakly dependent on the graphene layer length. Typical phase modulation values turn out to be about 15–20 degrees for minimal transmission coefficients of about 0.6–0.4; however, the phase modulation reaches a value of about 45 degrees if the transmission coefficient modulation equals 50%.

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Section: Modal Decomposition Methods In a Rectangular Metal Waveguide...mentioning

confidence: 99%

Modulation of TE propagation modes in rectangular metal waveguide with integrated graphene structure in the sub-terahertz frequency range

Shkerdin

Alkorre

et al. 2016

J. Opt.

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“…Koodalil et al 27,28 developed a technique that uses shear horizontal guided waves generated with periodic permanent magnet electromagnetic acoustic transducers (PPM EMATs) to quantify the interfacial adhesion of aluminium-epoxy-aluminium tri-layer in a lap shear joint. Simonetti, 29 Shkerdin and Glorieux 30 and Laperre and Thys 31 presented the theoretical aspects of Lamb wave propagation in bilayer consisting of a metal plate coated by a highly absorptive viscoelastic coating rubber layer. Bostron et al 22 demonstrated the feasibility of guided ultrasonic interface waves (similar to a leaky Rayleigh-like wave on the stiff solid) at a soft–stiff boundary to evaluate the bond between coatings and metal structures using several wave features such as amplitude ratio, pulse width and frequency ratio.…”

Section: Introductionmentioning

confidence: 99%

A study on the use of fundamental antisymmetric-like guided wave for health monitoring of elastic–viscoelastic bilayer structures

Ghose

Panda

Balasubramaniam

2022

Structural Health Monitoring

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This study investigates the ultrasonic guided wave propagation in an elastic–viscoelastic (steel–rubber) bilayer structure. 2D finite element models are developed in the frequency domain to simulate the wave propagation in the steel–rubber bilayer structure. The guided wave A0 mode is generated in the bilayer with a contact L-wave probe and detected with an out-of-plane laser vibrometer. Several wave features, such as amplitude, phase velocity and phase delay, are measured and compared to determine the characteristic changes of the A0 wave mode in the steel layer alone as well as in the bilayer structure. Studies are also performed for the bilayer structure when excited from the steel and rubber surfaces. The amplitude and phase velocity of the A0 mode are reduced in the bilayer compared to the steel layer alone. The phase velocity of the A0 wave mode in the bilayer does not depend on the viscoelastic properties of the rubber layer, rather depends only on the elastic properties of the rubber layer. The viscoelastic rubber layer in the bilayer structure does not sustain any independent wave mode; instead, it carries the A0 mode of the steel layer alone as a modified A0 wave mode in the bilayer structure. A parametric numerical study of the viscoelasticity of the rubber layer in the bilayer structure shows that the attenuation of the modified A0 mode in the bilayer is more affected by the bulk S-wave attenuation than the bulk L-wave attenuation. The rate of attenuation of the modified A0 mode in the bilayer is faster on the rubber surface than on the steel surface. A study on the A0 wave mode interaction with the interfacial disbond between steel and rubber layers is also carried out.

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“…In the field of non-destructive material characterisation, the modal decomposition is often favoured. Shkerdin and Glorieux 1,2 have investigated Lamb mode propagation through a composite plate consisting of two parallel layers of different materials with a finite length delamination. The method to calculate the transmitted and reflected fields was based on a modal expansion of each field in terms of propagating and evanescent modes.…”

Section: Introductionmentioning

confidence: 99%

The significance of the evanescent spectrum in structure-waveguide interaction problems

Tsouvalas

Dalen

Metrikine

2015

The Journal of the Acoustical Society of America

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Modal decomposition is often applied in elastodynamics and acoustics for the solution of problems related to propagation of mechanical disturbances in waveguides. One of the key elements of this method is the solution of an eigenvalue problem for obtaining the roots of the dispersion equation, which signify the wavenumbers of the waves that may exist in the system. For non-dissipative media, the wavenumber spectrum consists of a finite number of real roots supplemented by infinitely many imaginary and complex ones. The former refer to the propagating modes in the medium, whereas the latter constitute the so-called evanescent spectrum. This study investigates the significance of the evanescent spectrum in structure-waveguide interaction problems. Two cases are analysed, namely, a beam in contact with a fluid layer and a cylindrical shell interacting with an acousto-elastic waveguide. The first case allows the introduction of a modal decomposition method and the establishment of appropriate criteria for the truncation of the modal expansions in a simple mathematical framework. The second case describes structure-borne wave radiation in an offshore environment during the installation of a pile with an impact hammer-a problem that has raised serious concerns in recent years due to the associated underwater noise pollution.

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Interaction of lamb modes with delaminations in plates coated by highly absorbing materials

Cited by 11 publications

References 21 publications

Modulation of TE propagation modes in rectangular metal waveguide with integrated graphene structure in the sub-terahertz frequency range

Modulation of TE propagation modes in rectangular metal waveguide with integrated graphene structure in the sub-terahertz frequency range

A study on the use of fundamental antisymmetric-like guided wave for health monitoring of elastic–viscoelastic bilayer structures

The significance of the evanescent spectrum in structure-waveguide interaction problems

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