Application of arbitrary pulse width and position trains for the correlation sidelobes reduction for narrowband transducers

Svilainis, Linas; Aleksandrovas, Arturas

doi:10.1016/j.ultras.2013.04.001

Cited by 12 publications

(11 citation statements)

References 17 publications

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“…Note that due to cross-correlation properties [30][31][32][33][34], x R1W (t) and x R2W (t) are compressed versions of the original echoes s R1 (t) and s R2 (t) that retain the original frequency information thus its separation will be easier. Once these are properly gated, cross-correlation x R12W (t) between them can be calculated in frequency domain as:…”

Section: Pulse-echo Parametersmentioning

confidence: 99%

Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution

Rodríguez-Martínez

Svilainis

Dumbrava

et al. 2014

NDT & E International

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Svilainis, L.; V. Dumbrava; Dumbrava, V.; Salazar Afanador, A. (2014). Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution. NDT and E International. 66:117-127. doi:10.1016/j.ndteint.2014 AbstractA new method for the automatic and simultaneous measurement of phase velocity and thickness for thin composite plates was developed based on Ping He's method, without any need of a priori knowledge of the material parameters. Two composites were analyzed: a block of clean epoxy and a thin specimen of glass-fiber reinforced plastic produced by Resin TransferMolding. The proposed method combines cross-correlation functions and iterative deconvolution for accurate measurement of times of flight and gating. The new method has demonstrated to be more accurate than conventional Ping He's method, and can be implemented automatically thus saving processing time and increasing accuracy.

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Section: Pulse-echo Parametersmentioning

confidence: 99%

Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution

Rodríguez-Martínez

Svilainis

Dumbrava

et al. 2014

NDT & E International

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“…In this work, we present the development of the complete laser ultrasound source. Targeted applications are the synthetic aperture focusing technique (SAFT) [10], [65]- [68], photoacoustics [53]- [63] and the transducer spatial sensitivity evaluation and calibration [69]- [72]. The whole laser system is compact and lightweight.…”

Section: Introductionmentioning

confidence: 99%

Compact Laser Driver for Ultrasonic Arbitrary Position and Width Pulse Sequences Generation

Svilainis

Chaziachmetovas

Eidukynas

et al. 2021

IEEE Trans. Instrum. Meas.

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Laser ultrasound offers several benefits in comparison to immersion or air coupled ultrasound: it directly generates stress on the sample surface; it has a wide bandwidth and a small acoustic source can be produced. Conventionally, high power pulsed lasers are required therefore equipment is bulky and expensive. Here we propose to use mid-power laser diodes, which are small and low cost. To solve the low signal amplitude problem with lower power lasers, the use of spread spectrum signal, arbitrary position and width binary pulse sets is proposed. To date, a laser driver for this task has not been available. This paper describes the development of such a compact driver, where the essential electronics occupy an area of 10x20 mm. The whole system with a fixture for kinematic mount is comparable in size to a conventional piezoelectric ultrasonic transducer. The driver can supply pulse sets of up to 40 A. Individual pulse duration can vary between 20 ns to 1000 ns (0.5-25 MHz ultrasound range) and the total pulse train duration is limited by the laser type used. Experiments show that up to 10 s long pulse sets can be used at 10 A current, without laser degradation. Current waveforms, beam profile and optical response signals were measured for three rectified topologies. It was concluded, that the GaN based constant current switch topology has the best performance, but a power MOSFET in a source current feedback topology can also be used to generate pulses down to 20 ns. Photoacoustic response signals from chirp and phase shift keying modulation have been demonstrated.

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“…Despite all these problems, and because of the continuous improvement in air-coupled transducers [4], electronics, signal-processing-like coded excitation [5,6], and inspection techniques, there are good records of successful applications in different fields and by different groups [7].…”

Section: Introductionmentioning

confidence: 99%

Air-Coupled and Resonant Pulse-Echo Ultrasonic Technique

Álvarez-Arenas

Camacho

2019

Sensors

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An ultrasonic, resonant, pulse-echo, and air-coupled nondestructive testing (NDT) technique is presented. It is intended for components, with regular geometries where it is possible to excite resonant modes, made of materials that have a high acoustic impedance (Z) and low attenuation coefficient (α). Under these conditions, these resonances will present a very large quality factor (Q) and decay time (τ). This feature is used to avoid the dead zone, produced by the echo coming from the first wall, by receiving the resonant echo from the whole specimen over a longer period of time. This echo is analyzed in the frequency domain to determine specimen resonant frequency, which can be further used to determine either velocity or thickness. Using wideband air-coupled transducers, we tested the technique on plates (steel, aluminum, and silicone rubber) by exciting the mode of the first thickness. As expected, the higher the Z and the lower the α, the better the technique performed. Sensitivity to deviations of the angle of incidence away from normal (±2°) and the possibility to generate shear waves were also studied. Then, it was tested on steel cylindrical pipes that had different wall thicknesses and diameters. Finally, the use of this technique to generate C-Scan images of steel plates with different thicknesses was demonstrated.

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Application of arbitrary pulse width and position trains for the correlation sidelobes reduction for narrowband transducers

Cited by 12 publications

References 17 publications

Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution

Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution

Compact Laser Driver for Ultrasonic Arbitrary Position and Width Pulse Sequences Generation

Air-Coupled and Resonant Pulse-Echo Ultrasonic Technique

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