Investigation of elastic modes propagating in multi-wire helical waveguides

Treyssède, Fabien; Laguerre, Laurent

doi:10.1016/j.jsv.2009.11.021

Cited by 86 publications

(77 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Without PML (γ=1), this expression coincides with the results standardly found for closed waveguide problems [48,49]. With PMLs, M is complex and E tot is no longer real.…”

Section: Modal Filtering Of Radiation Modessupporting

confidence: 88%

Finite element computation of trapped and leaky elastic waves in open stratified waveguides

Treyssède¹,

Nguyen²,

Bonnet-Bendhia³

et al. 2014

Wave Motion

View full text Add to dashboard Cite

Elastic guided waves are of interest for inspecting structures due to their ability to propagate over long distances. In numerous applications, the guiding structure is surrounded by a solid matrix that can be considered as unbounded in the transverse directions. The physics of waves in such an open waveguide significantly differs from a closed waveguide, i.e. for a bounded cross-section. Except for trapped modes, part of the energy is radiated in the surrounding medium, yielding attenuated modes along the axis called leaky modes. These leaky modes have often been considered in non destructive testing applications, which require waves of low attenuation in order to maximize the inspection distance. The main difficulty with numerical modeling of open waveguides lies in the unbounded nature of the geometry in the transverse direction. This difficulty is particularly severe due to the unusual behavior of leaky modes: while attenuating along the axis, such modes exponentially grow along the transverse direction. A simple numerical procedure consists in using absorbing layers of artificially growing viscoelasticity, but large layers may be required. The goal of this paper is to explore another approach for the computation of trapped and leaky modes in open waveguides. The approach combines the so-called semi-analytical finite element method and a perfectly matched layer technique. Such an approach has already been successfully applied in scalar acoustics and electromagnetism. It is extended here to open elastic waveguides, which raises specific difficulties. In this paper, two-dimensional stratified waveguides are considered. As it reveals a rich structure, the numerical eigenvalue spectrum is analyzed in a first step. This allows to clarify the spectral objects calculated with the method, including radiation modes, and their dependency on the perfectly matched layer parameters. In a second step, numerical dispersion curves of trapped and leaky modes are compared to analytical results.

show abstract

“…Without PML (γ=1), this expression coincides with the results standardly found for closed waveguide problems [48,49]. With PMLs, M is complex and E tot is no longer real.…”

Section: Modal Filtering Of Radiation Modessupporting

confidence: 88%

Finite element computation of trapped and leaky elastic waves in open stratified waveguides

Treyssède¹,

Nguyen²,

Bonnet-Bendhia³

et al. 2014

Wave Motion

View full text Add to dashboard Cite

show abstract

“…Here, to ensure low dispersion, an appropriate thickness of the wire and suitable mean -helical and conical configurations due to curvature effect were considered for selection of waveguide dimensions using our earlier approaches [17][18][21][22][23] . Studies of waves in helical waveguides are reported in literature [25][26] with applications in civil structures. The elastic wave dispersion effects were modelled for cylindrical and helix geometries using a finite element approach in a non-orthonormal coordinate system.…”

Section: Ultrasonic Waves In Stepped-helical and Conical Waveguidesmentioning

confidence: 99%

“…A straight waveguide sensor system was reported 9 for measuring the vitrification melter temperature. The guided wave behaviour was studied in different curvature structures of helical and spiral ultrasonic waveguide configurations [17][18][19][20][21][25][26] for designing the distributed temperature measurement sensor. Here, the stepped and conical waveguides are designed based on this approach for measuring the distributed temperature measurements in a high-temperature furnace.…”

Section: Introductionmentioning

confidence: 99%

Distributed temperature sensors development using an stepped-helical ultrasonic waveguide

Periyannan

Rajagopal

Balasubramaniam

2018

AIP Conference Proceedings

View full text Add to dashboard Cite

“…The studies on waves in helical waveguides have been previously reported on acoustic waves, 25 electromagnetic waves 26 and elastic waves 27,28 with applications in civil structures. For avoiding dispersion effects due to curvature, the recommended helix diameter 21 is such that the ratio a of the helix diameter (D) to the torsional mode wavelength (λ T ) must be maintained above 2 as defined below:…”

Section: Helical Waveguide Designmentioning

confidence: 99%

Torsional mode ultrasonic helical waveguide sensor for re-configurable temperature measurement

2016

View full text Add to dashboard Cite

This paper introduces an ultrasonic torsional mode based technique, configured in the form of a helical “spring-like” waveguide, for multi-level temperature measurement. The multiple sensing levels can be repositioned by stretching or collapsing the spring to provide simultaneous measurements at different desired spacing in a given area/volume. The transduction is performed using piezo-electric crystals that generate and receive T(0,1) mode in a pulse echo mode. The gage lengths and positions of measurements are based on machining multiple reflector notches in the waveguide at required positions. The time of fight (TOF) measurements between the reflected signals from the notches provide local temperatures that compare well with co-located thermocouples.

show abstract

Investigation of elastic modes propagating in multi-wire helical waveguides

Cited by 86 publications

References 27 publications

Finite element computation of trapped and leaky elastic waves in open stratified waveguides

Finite element computation of trapped and leaky elastic waves in open stratified waveguides

Distributed temperature sensors development using an stepped-helical ultrasonic waveguide

Torsional mode ultrasonic helical waveguide sensor for re-configurable temperature measurement

Contact Info

Product

Resources

About