Laser ultrasound for the non contact characterisation of the mechanical properties of materials

B. Culshaw, B.L. Sorazu, S.G. Pierce, Campbell S.R. McKee, G.J. Thursby

Research output: Contribution to conferencePaper

Abstract

We present our perspectives on using laser ultrasound, coupled with optical detection, to characterise the properties of plate like structures. The laser source launches a wideband signal in spatial and temporal domains exciting a Lamb wave spectrum over several octaves. Optical detection picks out the modal dispersion curves and inverting these mathematically presents values for thickness, density, modulus and Poisson ratio with confidence levels of a few per cent. Our investigations have compared approaches to dispersion curve measurement involving both 2-D and short time FFT to examine different areas of the specimen. We have compared high peak power impulse excitation with synthetic pulse generation using frequency scanned (or Pseudo Random Binary Sequence pulsed) low power sources based on semiconductor lasers or fibre amplifier based systems. A thorough analysis of the numerical inversion process has demonstrated that, with careful optimisation, the data obtained from the sample may be confidently inverted. Our demonstrations to date have been on large scale (mm thick by cm longitudinal dimensions) samples and studies of the application of the concepts to micro-systems are currently under way.
Original languageEnglish
Publication statusUnpublished - Jan 2008
Event1st international conference on laser ultrasonics science, technology and applications - Montreal, Canada
Duration: 16 Jul 200818 Jul 2008

Conference

Conference1st international conference on laser ultrasonics science, technology and applications
CityMontreal, Canada
Period16/07/0818/07/08

Fingerprint

mechanical properties
thickness ratio
Lamb waves
octaves
fast Fourier transformations
Poisson ratio
curves
lasers
impulses
confidence
amplifiers
semiconductor lasers
inversions
broadband
optimization
fibers
pulses
excitation

Keywords

  • laser ultrasound
  • lamb wave propagation
  • material properties measurement

Cite this

Culshaw, B., Sorazu, B. L., Pierce, S. G., McKee, C. S. R., & Thursby, G. J. (2008). Laser ultrasound for the non contact characterisation of the mechanical properties of materials. Paper presented at 1st international conference on laser ultrasonics science, technology and applications, Montreal, Canada, .
Culshaw, B. ; Sorazu, B.L. ; Pierce, S.G. ; McKee, Campbell S.R. ; Thursby, G.J. / Laser ultrasound for the non contact characterisation of the mechanical properties of materials. Paper presented at 1st international conference on laser ultrasonics science, technology and applications, Montreal, Canada, .
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abstract = "We present our perspectives on using laser ultrasound, coupled with optical detection, to characterise the properties of plate like structures. The laser source launches a wideband signal in spatial and temporal domains exciting a Lamb wave spectrum over several octaves. Optical detection picks out the modal dispersion curves and inverting these mathematically presents values for thickness, density, modulus and Poisson ratio with confidence levels of a few per cent. Our investigations have compared approaches to dispersion curve measurement involving both 2-D and short time FFT to examine different areas of the specimen. We have compared high peak power impulse excitation with synthetic pulse generation using frequency scanned (or Pseudo Random Binary Sequence pulsed) low power sources based on semiconductor lasers or fibre amplifier based systems. A thorough analysis of the numerical inversion process has demonstrated that, with careful optimisation, the data obtained from the sample may be confidently inverted. Our demonstrations to date have been on large scale (mm thick by cm longitudinal dimensions) samples and studies of the application of the concepts to micro-systems are currently under way.",
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Culshaw, B, Sorazu, BL, Pierce, SG, McKee, CSR & Thursby, GJ 2008, 'Laser ultrasound for the non contact characterisation of the mechanical properties of materials' Paper presented at 1st international conference on laser ultrasonics science, technology and applications, Montreal, Canada, 16/07/08 - 18/07/08, .

Laser ultrasound for the non contact characterisation of the mechanical properties of materials. / Culshaw, B.; Sorazu, B.L.; Pierce, S.G.; McKee, Campbell S.R.; Thursby, G.J.

2008. Paper presented at 1st international conference on laser ultrasonics science, technology and applications, Montreal, Canada, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Laser ultrasound for the non contact characterisation of the mechanical properties of materials

AU - Culshaw, B.

AU - Sorazu, B.L.

AU - Pierce, S.G.

AU - McKee, Campbell S.R.

AU - Thursby, G.J.

PY - 2008/1

Y1 - 2008/1

N2 - We present our perspectives on using laser ultrasound, coupled with optical detection, to characterise the properties of plate like structures. The laser source launches a wideband signal in spatial and temporal domains exciting a Lamb wave spectrum over several octaves. Optical detection picks out the modal dispersion curves and inverting these mathematically presents values for thickness, density, modulus and Poisson ratio with confidence levels of a few per cent. Our investigations have compared approaches to dispersion curve measurement involving both 2-D and short time FFT to examine different areas of the specimen. We have compared high peak power impulse excitation with synthetic pulse generation using frequency scanned (or Pseudo Random Binary Sequence pulsed) low power sources based on semiconductor lasers or fibre amplifier based systems. A thorough analysis of the numerical inversion process has demonstrated that, with careful optimisation, the data obtained from the sample may be confidently inverted. Our demonstrations to date have been on large scale (mm thick by cm longitudinal dimensions) samples and studies of the application of the concepts to micro-systems are currently under way.

AB - We present our perspectives on using laser ultrasound, coupled with optical detection, to characterise the properties of plate like structures. The laser source launches a wideband signal in spatial and temporal domains exciting a Lamb wave spectrum over several octaves. Optical detection picks out the modal dispersion curves and inverting these mathematically presents values for thickness, density, modulus and Poisson ratio with confidence levels of a few per cent. Our investigations have compared approaches to dispersion curve measurement involving both 2-D and short time FFT to examine different areas of the specimen. We have compared high peak power impulse excitation with synthetic pulse generation using frequency scanned (or Pseudo Random Binary Sequence pulsed) low power sources based on semiconductor lasers or fibre amplifier based systems. A thorough analysis of the numerical inversion process has demonstrated that, with careful optimisation, the data obtained from the sample may be confidently inverted. Our demonstrations to date have been on large scale (mm thick by cm longitudinal dimensions) samples and studies of the application of the concepts to micro-systems are currently under way.

KW - laser ultrasound

KW - lamb wave propagation

KW - material properties measurement

UR - http://www.ndt.net/article/laser-ut2008/papers/Culshaw%20LU2008.pdf

M3 - Paper

ER -

Culshaw B, Sorazu BL, Pierce SG, McKee CSR, Thursby GJ. Laser ultrasound for the non contact characterisation of the mechanical properties of materials. 2008. Paper presented at 1st international conference on laser ultrasonics science, technology and applications, Montreal, Canada, .