High Frequency Guided Waves for Disbond Detection in Multi-Layered Structures

This paper is focused on dispersive properties of lossless planar layered structures with media having positive constitutive parameters (permittivity and permeability), possibly uniaxially anisotropic. Some of these properties have been derived in the past with reference to specific simple layered structures, and are here established with more general proofs, valid for arbitrary layered structures with positive parameters. As a first step, a simple application of the Smith chart to the relevant dispersion equation is used to prove that evanescent (or plasmonic-type) waves cannot be supported by layers with positive parameters. The main part of the paper is then focused on a generalization of a common graphical solution of the dispersion equation, in order to derive some general properties about the behaviour of the wavenumbers of surface waves as a function of frequency. The wavenumbers normalized with respect to frequency are shown to be always increasing with frequency, and at high frequency they tend to the highest refractive index in the layers. Moreover, two surface waves with the same polarization cannot have the same wavenumber at a given frequency. The low-frequency behaviours are also briefly addressed. The results are derived by means of a suitable application of Foster’s theorem.

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Scattering of ultrasonic guided waves by heterogeneous interfaces in elastic multi-layered structures

Wave Motion ◽

10.1016/j.wavemoti.2016.01.006 ◽

2016 ◽

Vol 63 ◽

pp. 68-82 ◽

Cited By ~ 6

Author(s):

Ricardo Leiderman ◽

Juan C. Figueroa ◽

Arthur M.B. Braga ◽

Fernando Alves Rochinha

Keyword(s):

Guided Waves ◽

Layered Structures ◽

Ultrasonic Guided Waves ◽

Heterogeneous Interfaces

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High-frequency radiation from earthquake sources in laterally varying layered structures

Geophysical Journal International ◽

10.1111/j.1365-246x.1987.tb01368.x ◽

1987 ◽

Vol 88 (1) ◽

pp. 43-79 ◽

Cited By ~ 12

Author(s):

V. erveny ◽

J. Pleinerova ◽

L. Klime ◽

I. P en ik

Keyword(s):

High Frequency ◽

Layered Structures ◽

Earthquake Sources ◽

Frequency Radiation ◽

High Frequency Radiation

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Absorption of high-frequency guided waves in a plasma-loaded waveguide

Physics of Plasmas ◽

10.1063/1.2799161 ◽

2007 ◽

Vol 14 (10) ◽

pp. 102107 ◽

Cited By ~ 8

Author(s):

A. Ganguli ◽

Kamran Akhtar ◽

R. D. Tarey

Keyword(s):

High Frequency ◽

Guided Waves

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Modeling guided waves to constrain the velocity structure of the oceanic crust in the subduction zone of eastern Alaska

10.5194/egusphere-egu2020-3268 ◽

2020 ◽

Author(s):

Xiaoyu Guan ◽

Yuanze Zhou ◽

Takashi Furumura

Keyword(s):

Subduction Zone ◽

Oceanic Crust ◽

High Frequency ◽

Subduction Zones ◽

Guided Waves ◽

Velocity Structure ◽

Guided Wave ◽

S Wave ◽

Arrival Times ◽

Velocity Models

<p>Fitting subduction zone guided waves with synthetics is an ideal choice for studying the velocity structure of the oceanic crust. After an earthquake occurs in subduction zones, seismic waves can be trapped in the low-velocity oceanic crust and propagated as guided waves. The arrival time and frequency characteristics of the guided waves can be used to image the velocity structure of the oceanic crust. The analysis and modeling based on guided wave observations provide a rare opportunity to understand the velocity structure of the oceanic crust and the variations in oceanic crustal materials during the subduction process.</p><p>High-frequency guided waves have been observed in the subduction zone of eastern Alaska. On several sections, observed seismograms recorded by seismic stations show low-frequency (<2Hz) onsets ahead of the main high-frequency (>2Hz) guided waves. Differences in the arrival times and dispersion characteristics of seismic phases are related to the velocity structure of the oceanic crust, and the characteristics of coda waves are related to the distribution of elongated scatters in the oceanic crust. Through fitting the observed broadband waveforms and synthetics modeled with the 2-D FDM (Finite Difference Method), we obtain the preferred oceanic crustal velocity models for several sections in the subduction zone of eastern Alaska. The preferred models can explain the seismic phase arrival times, dispersions, and coda characteristics in the observed waveforms. With the obtained P- and S- wave models of velocity structures on several sections, the material compositions they represent are deduced, and the variations of oceanic crustal materials during subducting can be understood. This provides new evidence for studying the details of the subduction process in the subduction zone of eastern Alaska.</p>

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Stochastic high-frequency precession of magnetization in layered structures with antiferromagnetic ordering

Physics of the Solid State ◽

10.1134/1.1825552 ◽

2004 ◽

Vol 46 (11) ◽

pp. 2073-2080

Author(s):

A. M. Shutyi ◽

D. I. Sementsov

Keyword(s):

High Frequency ◽

Layered Structures ◽

Antiferromagnetic Ordering

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Advanced debonding detection technique for aerospace composite structures

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-10-2020-0222 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Assunta Sorrentino ◽

Fulvio Romano ◽

Angelo De Fenza

Keyword(s):

High Frequency ◽

Composite Structures ◽

Guided Waves ◽

Plastic Material ◽

Impact Damage ◽

Small Scale ◽

Content Type ◽

Stiffened Panels ◽

Reinforced Plastic ◽

Debonding Detection

Purpose The purpose of this paper is to introduce a methodology aimed to detect debonding induced by low impacts energies in typical aeronautical structures. The methodology is based on high frequency sensors/actuators system simulation and the application of elliptical triangulation (ET) and probability ellipse (PE) methods as damage detector. Numerical and experimental results on small-scale stiffened panels made of carbon fiber-reinforced plastic material are discussed. Design/methodology/approach The damage detection methodology is based on high frequency sensors/actuators piezoceramics system enabling the ET and the PE methods. The approach is based on ultrasonic guided waves propagation measurement and simulation within the structure and perturbations induced by debonding or impact damage that affect the signal characteristics. Findings The work is focused on debonding detection via test and simulations and calculation of damage indexes (DIs). The ET and PE methodologies have demonstrated the link between the DIs and debonding enabling the identification of position and growth of the damage. Originality/value The debonding between two structural elements caused in manufacturing or in-service is very difficult to detect, especially when the components are in low accessibility areas. This criticality, together with the uncertainty of long-term adhesive performance and the inability to continuously assess the debonding condition, induces the aircrafts’ manufacturers to pursuit ultraconservative design approach, with in turn an increment in final weight of these parts. The aim of this research’s activity is to demonstrate the effectiveness of the proposed methodology and the robustness of the structural health monitoring system to detect debonding in a typical aeronautical structural joint.

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