Measurement of elastic nonlinearity using remote laser ultrasonics and CHeap Optical Transducers and dual frequency surface acoustic waves

Collison, Ian J.; Stratoudaki, Theodosia; Clark, Matt; Somekh, Mike

doi:10.1016/j.ultras.2008.07.003

Cited by 14 publications

(5 citation statements)

References 16 publications

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“…A similar measurement with a heterodyne laser interferometer was utilized to make SHG measurements of Rayleigh waves in a nickel superalloy [38]. Recent developments in laser instrumentation such as the CHeap Optical Transducer (CHOT) [111,112] where patterns are essentially deposited on the surface of a sample for laser generation or transmission, could eventually make laser interrogation portable and feasible in an in situ application. Laser-based generation and detection has also been utilized in vibro-acoustic measurements [112][113][114].…”

Section: Laser Methodsmentioning

confidence: 99%

“…Recent developments in laser instrumentation such as the CHeap Optical Transducer (CHOT) [111,112] where patterns are essentially deposited on the surface of a sample for laser generation or transmission, could eventually make laser interrogation portable and feasible in an in situ application. Laser-based generation and detection has also been utilized in vibro-acoustic measurements [112][113][114]. Signals from a laser detector are usually weak such that careful signal conditioning is essential to reliably extract the second harmonic signal.…”

Section: Laser Methodsmentioning

confidence: 99%

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Review of Second Harmonic Generation Measurement Techniques for Material State Determination in Metals

et al. 2014

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This paper presents a comprehensive review of the current state of knowledge of second harmonic generation (SHG) measurements, a subset of nonlinear ultrasonic nondestructive evaluation techniques. These SHG techniques exploit the material nonlinearity of metals in order to measure the acoustic nonlinearity parameter, β. In these measurements, a second harmonic wave is generated from a propagating monochromatic elastic wave, due to the anharmonicity of the crystal lattice, as well as the presence of microstructural features such as dislocations and precipitates. This article provides a summary of models that relate the different microstructural contributions to β, and provides details of the different SHG measurement and analysis techniques available, focusing on longitudinal and Rayleigh wave methods. The main focus of this paper is a critical review of the literature that utilizes these SHG methods for the nondestructive evaluation of plasticity, fatigue, thermal aging, creep, and radiation damage in metals.

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Section: Laser Methodsmentioning

confidence: 99%

Section: Laser Methodsmentioning

confidence: 99%

Review of Second Harmonic Generation Measurement Techniques for Material State Determination in Metals

et al. 2014

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“…28,29 The experiments presented in this article are based on the parametric interaction between a transducer generated pump SAW and a laser generated probe SAW. We have previously demonstrated the potential of this technique using cheap optical transducers (CHOTs) for generation and detection of ultrasound 34 and we now show its capabilities to measure material nonlinearity using laser ultrasonics. Laser ultrasound can overcome several shortcomings associated with the use of contact transducers: It is a remote and couplant free technique especially suitable for components with complex geometry and places with restricted access.…”

Section: Introductionmentioning

confidence: 91%

Measurement of material nonlinearity using surface acoustic wave parametric interaction and laser ultrasonics

Stratoudaki

Ellwood

Sharples

et al. 2011

The Journal of the Acoustical Society of America

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A dual frequency mixing technique has been developed for measuring velocity changes caused by material nonlinearity. The technique is based on the parametric interaction between two surface acoustic waves (SAWs): The low frequency pump SAW generated by a transducer and the high frequency probe SAW generated and detected using laser ultrasonics. The pump SAW stresses the material under the probe SAW. The stress (typically <5 MPa) is controlled by varying the timing between the pump and probe waves. The nonlinear interaction is measured as a phase modulation of the probe SAW and equated to a velocity change. The velocity-stress relationship is used as a measure of material nonlinearity. Experiments were conducted to observe the pump-probe interaction by changing the pump frequency and compare the nonlinear response of aluminum and fused silica. Experiments showed these two materials had opposite nonlinear responses, consistent with previously published data. The technique could be applied to life-time predictions of engineered components by measuring changes in nonlinear response caused by fatigue.

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“…Their collinear interaction results in a phase modulation of the high frequency wave which was measured by Jacob et al 17 and Vila et al 18 using longitudinal waves. In Collison et al 19 we first proposed an experimental technique based on laser ultrasonics and optical transducers that used a dynamic method to observe the acoustoelastic effect in solids. The technique was based on the collinear parametric interaction of SAWs.…”

Section: Introductionmentioning

confidence: 99%

“…It measures the velocity change of a high frequency probe wave due to the induced stress from a second large amplitude low frequency pump wave. 19,25 By controlling the delay between the generation of the two waves, their interaction point, hence the applied stress, can be selected. The duration of the probe wave packet (T packet ) is short compared to the period of the pump wave (T pump ): T packet < 1=4T pump .…”

Section: Introductionmentioning

confidence: 99%

Determination of the acoustoelastic coefficient for surface acoustic waves using dynamic acoustoelastography: An alternative to static strain

Ellwood

Stratoudaki

Sharples

et al. 2014

The Journal of the Acoustical Society of America

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The third-order elastic constants of a material are believed to be sensitive to residual stress, fatigue, and creep damage. The acoustoelastic coefficient is directly related to these third-order elastic constants. Several techniques have been developed to monitor the acoustoelastic coefficient using ultrasound. In this article, two techniques to impose stress on a sample are compared, one using the classical method of applying a static strain using a bending jig and the other applying a dynamic stress due to the presence of an acoustic wave. Results on aluminum samples are compared. Both techniques are found to produce similar values for the acoustoelastic coefficient. The dynamic strain technique however has the advantages that it can be applied to large, real world components, in situ, while ensuring the measurement takes place in the nondestructive, elastic regime.

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Measurement of elastic nonlinearity using remote laser ultrasonics and CHeap Optical Transducers and dual frequency surface acoustic waves

Cited by 14 publications

References 16 publications

Review of Second Harmonic Generation Measurement Techniques for Material State Determination in Metals

Review of Second Harmonic Generation Measurement Techniques for Material State Determination in Metals

Measurement of material nonlinearity using surface acoustic wave parametric interaction and laser ultrasonics

Determination of the acoustoelastic coefficient for surface acoustic waves using dynamic acoustoelastography: An alternative to static strain

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