Time-frequency-domain formulation of ultrasonic frequency analysis

Simpson, W.A.

doi:10.1121/1.1903512

Cited by 28 publications

(11 citation statements)

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“…Analysis of ultrasonic waves which have been transmitted through a sample allow acoustic and hence mechanical parameters of the sample to be extracted. In most cases, signals are not overlapped and both time domain [1] and frequency domain [2,3] analysis can be used to determine parameters such as wave velocity, attenuation or density.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic characterization of porous silicon using a genetic algorithm to solve the inverse problem

Bustillo

Fortineau

Gautier

et al. 2014

NDT & E International

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International audienceThis paper presents a method for ultrasonic characterization of porous silicon in which a genetic algorithm based optimization is used to solve the inverse problem. A one dimensional model describing wave propagation through a water immersed sample is used in order to compute transmission spectra. Then, a water immersion wide bandwidth measurement is performed using insertion/substitution method and the spectrum of signals transmitted through the sample is calculated using Fast Fourier Transform. In order to obtain parameters such as thickness, longitudinal wave velocity or density, a genetic algorithm based optimization is used.A validation of the method is performed using aluminum plates with two different thicknesses as references: a good agreement on acoustical parameters can be observed, even in the case where ultrasonic signals overlap.Finally, two samples, i.e. a bulk silicon wafer and a porous silicon layer etched on silicon wafer, are evaluated. A good agreement between retrieved values and theoretical ones is observed. Hypothesis to explain slight discrepancies are proposed

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Section: Introductionmentioning

confidence: 99%

Ultrasonic characterization of porous silicon using a genetic algorithm to solve the inverse problem

Bustillo

Fortineau

Gautier

et al. 2014

NDT & E International

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“…The velocities of the separated shear‐wave modes are different. When two shear‐wave modes travel in the same direction, interference effects are produced . After the two shear‐wave modes with interference effects are reflected from the steel‐member rear side, they return to the shear‐wave transceiver probe.…”

Section: Theorymentioning

confidence: 70%

“…The synthesis signal of the two shear‐wave modes contains stress information, which is the basis of this method, to measure stress by evaluating the change of the shear‐wave spectrum. Simpson investigated the birefringence‐induced interference effect of two shear waves and established the fundamental procedures for measuring stress using the shear‐wave spectrum. Blinka and Sachse investigated the shear‐wave echo power spectrum, and their experimental results showed that the shear‐wave spectrum changed with the stress.…”

Section: Introductionmentioning

confidence: 78%

Comparison of the L cr wave TOF and shear‐wave spectrum methods for the uniaxial absolute stress evaluation of steel members

Teng

et al. 2019

Struct Control Health Monit

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The absolute stress of steel members is a key parameter for determining the performance of steel structures. Compared with other nondestructive evaluation methods, ultrasonic methods, which correlate material stress with ultrasonic velocity, have received the greatest amount of research attention. In this study, we investigated the measurement of the absolute stress distribution of steel members using two ultrasonic methods: a longitudinal critically refracted (Lcr) wave method and a shear wave method. The Lcr wave is generated from the longitudinal wave mode conversion and exhibits the greatest sensitivity to stress. The shear waves are generated by the birefringence effect, and their synthesis signal spectrum exhibits a minimum that varies with stress. A comparison of the two absolute stress evaluation methods is performed. Specifically, four steel members with identical dimensions and materials are used to investigate the discreteness of the calibrated parameters. The uniaxial absolute stress distributions of two steel members with variable cross sections are measured using the two methods and verified using the traditional strain gauge method. The results show that the uniaxial stress distributions of the two steel members can be evaluated by both the Lcr wave time-of-flight method and the shear-wave spectrum method, although the latter is more accurate for the measurement of stress distribution. Furthermore, the measurement principles, parametric calibrations, sensitivity, accuracy, and repeatability of the two methods are compared, and their applicability is discussed. KEYWORDS acoustoelastic effect, birefringence effect, Lcr wave TOF method, nondestructive stress measurement, shear-wave spectrum method, steel members, uniaxial absolute stress

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“…The effect of overlapping modes and other interacting waves is to cause high-frequency modulation superimposed on the dispersion curve of the fundamental mode (Simpson, 1974;SanchezSalinero et al, 1987;Stoll et al, 1994b;Bautista, 1994). In order to reduce the effect of both organized and unorganized noise, a variety of different strategies have been employed.…”

Section: Introductionmentioning

confidence: 98%

Remote determination of in situ sediment parameters using Love waves

Bautista

Stoll

1995

The Journal of the Acoustical Society of America

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In situ properties of near-bottom sediments are determined using an experimental technique based on the dispersive properties of horizontally polarized surface waves generally known as Love waves. This technique basically consists of generating the Love waves, analyzing the recorded seismic signals to determine dispersion, and, finally, mathematically inverting the dispersion data to obtain a geoacoustic model of the sediment. In the field experiments, Love waves are generated using a torsional source and the generated signals are recorded with a linear array of gimbaled geophones that measure transverse horizontal motion. Experimental dispersion curves (wave velocity versus frequency), are then obtained from the recorded wavelets. These velocity waveforms are usually composed of overlapping modes and in order to reduce the influence of modal interference on the experimental phase velocity dispersion curves, a phase-matched filter is used to extract a smoothed phase velocity dispersion curve for the fundamental mode. The dispersion curve is then mathematically inverted to obtain a sediment model using a constrained least-squares method with singular-value decomposition and it is shown that the maximum parameter resolution depth can be estimated from the generalized inverse. Practical use of the technique is demonstrated by an analysis of the results of a field experiment carried out in a marine sand sediment. ¸

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Time-frequency-domain formulation of ultrasonic frequency analysis

Cited by 28 publications

References 0 publications

Ultrasonic characterization of porous silicon using a genetic algorithm to solve the inverse problem

Ultrasonic characterization of porous silicon using a genetic algorithm to solve the inverse problem

Comparison of the L cr wave TOF and shear‐wave spectrum methods for the uniaxial absolute stress evaluation of steel members

Remote determination of in situ sediment parameters using Love waves

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