A Calibration Technique for Ultrasonic Immersion Transducers and Challenges in Moving Towards Immersion Based Harmonic Imaging

Chakrapani, Sunil Kishore; Barnard, Daniel J.

doi:10.1007/s10921-019-0613-6

Cited by 8 publications

(6 citation statements)

References 35 publications

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“…When the propagation distance or the sample thickness was insufficient, similar behavior was observed for the measured β of water and aluminum [25,26]. The behavior of γ after total corrections is shown in Figure 7b as a function of input power level.…”

Section: Plot Of 𝐴 Vs 𝐴 and Source Nonlinearity Checksupporting

confidence: 68%

“…Furthermore, the y-intercept of the fitted line may not pass through the origin. The non-zero y-intercept indicates the amount of source nonlinearity included in the measurement system or the noise floor of the measurement system [ 25 ]. Therefore, the relationship plot of

vs.

obtained using the measurement data provides insight into the behavior of nonlinear solid samples and the stability of the measurement system against source nonlinearity.…”

Section: Third Harmonic Generation Measurement and Effect Of Various ...mentioning

confidence: 99%

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Highly Sensitive Detection of Microstructure Variation Using a Thickness Resonant Transducer and Pulse-Echo Third Harmonic Generation

et al. 2023

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In nonlinear ultrasound testing, the relative nonlinear parameter is conveniently measured as a sensitive means of detecting and imaging overall variation of microstructures and damages. Compared to the quadratic nonlinear parameter (β′), the cubic nonlinear parameter (γ′), calculated as the third harmonic amplitude divided by the cube of the fundamental amplitude, has generally a higher value, providing better sensitivity in nonlinear parameter mapping. Since the third harmonic amplitude is about two orders of magnitude lower than the fundamental amplitude, efficient excitation and highly sensitive reception of third harmonic is very important. In this paper, we explore an odd harmonic thickness resonant transducer that meets the requirements for pulse-echo third harmonic generation (THG) measurements. We also address the problem of source nonlinearity that may be present in the measured amplitude of the third harmonic and propose a method to properly correct it. First, we measure γ′ for a series of aluminum specimens using the through-transmission method to observe the behavior of γ′ as a function of specimen thickness and input voltage, and examine the effects of various corrections such as attenuation, diffraction and source nonlinearity. Next, we apply the odd harmonic resonant transducer to pulse-echo THG measurements of precipitation heat-treated specimens. It is shown that such transducer is very effective in generation and detection of fundamental and third harmonics under finite amplitude toneburst excitation. The highly sensitive detectability of γ′ are presented as a function of aging time, and the sensitivity of γ′ is compared with that of β′ and β′2.

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Section: Plot Of 𝐴 Vs 𝐴 and Source Nonlinearity Checksupporting

confidence: 68%

vs.

obtained using the measurement data provides insight into the behavior of nonlinear solid samples and the stability of the measurement system against source nonlinearity.…”

Section: Third Harmonic Generation Measurement and Effect Of Various ...mentioning

confidence: 99%

Highly Sensitive Detection of Microstructure Variation Using a Thickness Resonant Transducer and Pulse-Echo Third Harmonic Generation

et al. 2023

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“…The absolute measurement of the received displacement generally requires the use of a calibrated receiving transducer. In case of an air-coupled receiver, however, the reciprocity-based calibration [ 19 , 20 ] is very difficult to perform because of high attenuation in the air. Due to the difficulty of obtaining calibration measurements, it is possible to use an electrical output signal instead of the received displacement in the measurement of nonlinear parameters.…”

Section: Sound Beam Fields and Nonlinear Parametermentioning

confidence: 99%

“…Detection of second harmonic generation measurements using longitudinal waves has been conducted with contact piezoelectric transducers [ 1 , 2 , 3 , 4 , 5 , 6 ], capacitive transducers [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ], and laser interferometers [ 15 , 16 , 17 , 18 ]. An absolute measurement of material nonlinearity is possible using either capacitive transducers [ 9 , 12 ] or contact piezoelectric transducers using a calibration procedure [ 19 , 20 ] in which the absolute displacement amplitude of the fundamental and second harmonic waves can be measured.…”

Section: Introductionmentioning

confidence: 99%

Absolute Measurement of Material Nonlinear Parameters Using Noncontact Air-Coupled Reception

et al. 2021

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Nonlinear ultrasound is often employed to assess microdamage or nonlinear elastic properties of a material, and the nonlinear parameter is commonly used to quantify damage sate and material properties. Among the various factors that influence the measurement of nonlinear parameters, maintaining a constant contact pressure between the receiver and specimen is important for repeatability of the measurement. The use of an air-coupled transducer may be considered to replace the contact receiver. In this paper, a method of measuring the relative and absolute nonlinear parameters of materials is described using an air-coupled transducer as a receiver. The diffraction and attenuation corrections are newly derived from an acoustic model for a two-layer medium and the nonlinear parameter formula with all corrections is defined. Then, we show that the ratio of the relative nonlinear parameter of the target sample to the reference sample is equal to that of the absolute nonlinear parameter, and this equivalence is confirmed by measurements on three systems of aluminum samples. The proposed method allows the absolute measurement of the nonlinear parameter ratio or the nonlinear parameter without calibration of the air-coupled receiver and removes restrictions on the selection of reference samples.

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“…Nonlinear ultrasound methods often measure the second harmonic generation (SHG) to obtain a nonlinear parameter β, defined as the ratio of the second harmonic amplitude to the square of the fundamental wave amplitude, and draw conclusions about the material state. Nonlinear parameters can be measured, using longitudinal waves [7][8][9][10][11], Rayleigh waves [12][13][14], and Lamb waves [15][16][17]. Rayleigh waves require sufficient propagation distance to measure SHG; the measured nonlinearity is averaged over distance and cannot be localized.…”

Section: Introductionmentioning

confidence: 99%

Transmission Phase Control of Annular Array Transducers for Efficient Second Harmonic Generation in the Presence of a Stress-Free Boundary

Jeong

Shin

2021

Applied Sciences

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The through-transmission (TT) method is mainly used to measure the amplitude of the second harmonic from which the acoustic nonlinear parameter is determined for early damage detection of materials. The pulse echo (PE) method, however, has been excluded from nonlinear studies of solid materials because the stress-free boundary suppresses the generation of second harmonics. It is more demanding to develop the PE method for practical applications and this paper considers a novel phase shift technique of annular array transducers to improve second harmonic generation (SHG) at the stress-free boundary. The fundamental and second harmonic fields after phase-shifted radiation are calculated, and their received amplitudes are investigated. The phase difference between the two second harmonic components after reflection from the stress-free boundary is analyzed to explain the enhanced SHG. The PE method with optimal phase shift can generate an improved second harmonic amplitude as high as about 45% of the TT method. Four element array transducers are also found to be more efficient in improved SHG than two element transducers.

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A Calibration Technique for Ultrasonic Immersion Transducers and Challenges in Moving Towards Immersion Based Harmonic Imaging

Cited by 8 publications

References 35 publications

Highly Sensitive Detection of Microstructure Variation Using a Thickness Resonant Transducer and Pulse-Echo Third Harmonic Generation

Highly Sensitive Detection of Microstructure Variation Using a Thickness Resonant Transducer and Pulse-Echo Third Harmonic Generation

Absolute Measurement of Material Nonlinear Parameters Using Noncontact Air-Coupled Reception

Transmission Phase Control of Annular Array Transducers for Efficient Second Harmonic Generation in the Presence of a Stress-Free Boundary

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