Computing leaky Lamb waves for waveguides between elastic half-spaces using spectral collocation

Fuente: arXiv
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Autori principali: Georgiades, Evripides, Lowe, Michael J. S., Craster, Richard V.
Natura: Preprint
Pubblicazione: 2023
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author Georgiades, Evripides
Lowe, Michael J. S.
Craster, Richard V.
author_facet Georgiades, Evripides
Lowe, Michael J. S.
Craster, Richard V.
contents In non-destructive evaluation guided wave inspections, the elastic structure to be inspected is often embedded within other elastic media and the ensuing leaky waves are complex and non-trivial to compute; we consider the canonical example of an elastic waveguide surrounded by other elastic materials that demonstrates the fundamental issues with calculating the leaky waves in such systems. Due to the complex wavenumber solutions required to represent them, leaky waves pose significant challenges to existing numerical methods, with methods that spatially discretise the field to retrieve them suffering from the exponential growth of their amplitude far into the surrounding media. We present a spectral collocation method yielding an accurate and efficient identification of these modes, leaking into elastic half-spaces. We discretise the elastic domains and, depending on the exterior bulk wavespeeds, select appropriate mappings of the discretised domain to complex paths, in which the numerical solution decays and the physics of the problem are preserved. By iterating through all possible radiation cases, the full set of dispersion and attenuation curves are successfully retrieved and validated, where possible, against the commercially available software DISPERSE. As an independent validation, dispersion curves are obtained from finite element simulations of time-dependent waves using Fourier analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2306_10064
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Computing leaky Lamb waves for waveguides between elastic half-spaces using spectral collocation
Georgiades, Evripides
Lowe, Michael J. S.
Craster, Richard V.
Numerical Analysis
In non-destructive evaluation guided wave inspections, the elastic structure to be inspected is often embedded within other elastic media and the ensuing leaky waves are complex and non-trivial to compute; we consider the canonical example of an elastic waveguide surrounded by other elastic materials that demonstrates the fundamental issues with calculating the leaky waves in such systems. Due to the complex wavenumber solutions required to represent them, leaky waves pose significant challenges to existing numerical methods, with methods that spatially discretise the field to retrieve them suffering from the exponential growth of their amplitude far into the surrounding media. We present a spectral collocation method yielding an accurate and efficient identification of these modes, leaking into elastic half-spaces. We discretise the elastic domains and, depending on the exterior bulk wavespeeds, select appropriate mappings of the discretised domain to complex paths, in which the numerical solution decays and the physics of the problem are preserved. By iterating through all possible radiation cases, the full set of dispersion and attenuation curves are successfully retrieved and validated, where possible, against the commercially available software DISPERSE. As an independent validation, dispersion curves are obtained from finite element simulations of time-dependent waves using Fourier analysis.
title Computing leaky Lamb waves for waveguides between elastic half-spaces using spectral collocation
topic Numerical Analysis
url https://arxiv.org/abs/2306.10064