Dual-probe laser interferometer for structural health monitoring

Hurlebaus, Stefan; Jacobs, Laurence J.

doi:10.1121/1.2170442

Cited by 10 publications

(11 citation statements)

References 6 publications

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“…Compare the ratio of these absolute acoustic nonlinearity parameters to the ratio of the measured relative acoustic nonlinear parameters,/?' as 1.39 [10] versus the current 1.33.…”

Section: Methodsmentioning

confidence: 99%

“…A heterodyne laser interferometer system is used as a high fidehty, point-hke, hnear detection system to measure the out-of-plane particle velocity of a point on the specimen surface. This interferometric system has a frequency bandwidth of approximately 100 kHz to 15 MHz [10], and makes frequency-independent measurements without interfering with the process being monitored. Signal averaging (up to 1000 signals) is used to increase the signal-to-noise ration (SNR).…”

Section: Methodsmentioning

confidence: 99%

“…The slope of the Al-2024 specimen is 3.03 x 10' while the slope of the Al-6061 specimen is 4.03 x 10' . Using longitudinal waves, Yost and Cantrell [10] measured the absolute acoustic nonlinearity parameters (fi) of aluminum alloy Al-2024 and Al-6061 as 4.09 and 5.67, respectively. Compare the ratio of these absolute acoustic nonlinearity parameters to the ratio of the measured relative acoustic nonlinear parameters,/?'…”

Section: Methodsmentioning

confidence: 99%

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A Rayleigh Wave Technique to Measure the Acoustic Nonlinearity Parameter of Materials

Shui¹,

Jacobs²,

Qu³

et al. 2008

AIP Conference Proceedings

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Nonlinear ultrasonic techniques have shown great potential for evaluating accumulated damage early in the fatigue life, and ultimately for predicting remaining lifetime of a structural component. The acoustic nonlinearity parameter, a direct measure of the accumulated fatigue damage, is determined from the second harmonic amplitude in finite amplitude sinusoidal ultrasonic waves transmitted through the material. An absolute determination of the acoustic nonlinear parameter is notoriously difficult for several reasons. In this paper, a new experimental technique based on Rayleigh surface waves is presented for determining the absolute acoustic nonlinearity parameter of a relatively thin material specimen. Rayleigh waves are efficiently generated in a specimen by exciting at its edge, and the surface normal velocity of the propagating Rayleigh waves is measured with a laser interferometer system. The high efficiency of the excitation method allows us to drive the transmitting piezoelectric transducer as low as 60 Vpp, and thus to avoid the inherent harmonic distortion from the transducer. The absolute acoustic nonlinearity parameter is then determined from the measured magnitudes of the fundamental and second harmonic surface normal velocities. This technique is applied to determining the acoustic nonlinearity parameters of aluminum alloys 2024 and 6061; the results are compared with those available in the literature. The present technique is especially well-suited for relatively thin components, and much simpler and efficient than the traditional longitudinal wave technique.

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“…Compare the ratio of these absolute acoustic nonlinearity parameters to the ratio of the measured relative acoustic nonlinear parameters,/?' as 1.39 [10] versus the current 1.33.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A Rayleigh Wave Technique to Measure the Acoustic Nonlinearity Parameter of Materials

Shui¹,

Jacobs²,

Qu³

et al. 2008

AIP Conference Proceedings

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“…The elastic wave propagates through the aluminum wire and is detected by a laser Doppler vibrometer (LDV). The LDV is a powerful measurement tool which allows non-contact, high fidelity, point-like measurements over a wide frequency range [8]. As shown, the LDV is used to measure the axial particle velocity at the left end of the wire.…”

Section: A Single Wire Measurementsmentioning

confidence: 99%

“…The attenuation coefficient is estimated according to Eqn. (8), where the maximum amplitudes of the end reflections have been used in computations. Depicted in Fig.…”

Section: B Transmission Line Measurementsmentioning

confidence: 99%

Power Line Monitoring

Wilson

Hurlebaus

2007

2007 American Control Conference

Self Cite

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Overhead power lines are periodically inspected using both on-ground and helicopter-aided visual inspection. Factors including sun glare, cloud cover, close proximity to power lines, and rapidly changing visual circumstances make airborne inspection of power lines a particularly hazardous task. In this study, the feasibility of continuous, on-line monitoring of power lines using ultrasonic waves is considered. A sending/receiving transducer located on the power line generates an ultrasonic wave in the cable. A defect in the cable will cause a portion of the incident ultrasonic wave to be reflected back to the transducer. Data acquired by the transducer can be relayed to a central communication node via a wireless transmitter. The methodology developed in this study can also be applied to other cable monitoring applications, such as bridge cable monitoring, which would otherwise put human inspectors at risk.

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A new technique for measuring the acoustic nonlinearity of materials using Rayleigh waves

Shui

Kim

et al. 2008

NDT & E International

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Dual-probe laser interferometer for structural health monitoring

Cited by 10 publications

References 6 publications

A Rayleigh Wave Technique to Measure the Acoustic Nonlinearity Parameter of Materials

A Rayleigh Wave Technique to Measure the Acoustic Nonlinearity Parameter of Materials

Power Line Monitoring

A new technique for measuring the acoustic nonlinearity of materials using Rayleigh waves

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