Comparison of continuous-wave (CW) and tone-burst (TB) excitation modes in vibro-acoustography: Application for the non-destructive imaging of flaws

Mitri, F.G.; Greenleaf, James F.; Fatemi, Mostafa

doi:10.1016/j.apacoust.2008.03.005

Cited by 19 publications

(3 citation statements)

References 26 publications

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“…After characterizing the piezoelectret transducer as a hydrophone for detecting underwater low-frequency ultrasonic signals, images were produced following the same VA technique previously described in the CW mode schematically shown in figure 3. The ultrasonic power sources can be driven in either the CW or the burst mode, and both have their advantages as well as drawbacks [28]. Here, the CW mode was chosen and the low-frequency zone was set at 50 kHz, i.e.…”

Section: Vibro-acoustographymentioning

confidence: 99%

Piezoelectret-based hydrophone: an alternative device for vibro-acoustography

Medeiros

Kamimura

Altafim

et al. 2015

Meas. Sci. Technol.

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Piezoelectric polymers are highly desirable for ultrasound applications since their low acoustic impedance is much closer to the impedances of air and water than those of traditional piezoceramics. However, the piezoelectric effect observed in these poled polymers is limited to a few dozen picocoulombs per newton and requires very low-noise amplification. A different class of polymeric material known as piezoelectrets, presents piezoelectric effect in the same order of magnitude as those found on piezoceramics. This new class of materials has been explored in a wide range of applications such as flexible keyboards and airborne ultrasound transducers. Based on these polymers, we present here a new transducer for vibro-acoustography (VA), which is an ultrasonic image technique employed in medical diagnosis or material analysis based on ultrasound scattered by a target object. A calibration was carried out using a standard hydrophone, which is normally employed in VA. The average sensitivity of the transducer in the continuous wave mode was 1.712 mV Pa−1(−182.7 dB re 1 V Pa−1) with a maximum sensitivity of 18.25 mV Pa−1 (−154.8 dB re 1 V Pa−1) at its resonance frequency around 40 kHz. Subsequently, measurements in the burst mode and of directional sensitivity were taken and are presented here together with VA images obtained from a chicken bone and a metal sphere.

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Section: Vibro-acoustographymentioning

confidence: 99%

Piezoelectret-based hydrophone: an alternative device for vibro-acoustography

Medeiros

Kamimura

Altafim

et al. 2015

Meas. Sci. Technol.

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“…Nondestructive testing plays an important role in identifying and detection of internal defects and cracks in many industrial applications such as concrete structures, metal testing and surface flaw testing etc. There have been many nondestructive inspection methods for surface flaw [3], mainly visual inspection [4], magnetic particle testing [5], ultrasonic testing [6] etc. Workers must be experienced and skilled ,flaw can be inspected when using visual detection.…”

Section: Overview Of Nondestructive Inspection Techniquesmentioning

confidence: 99%

Intelligent Inspection of the High-Speed Train Bogie Flaw Based on Eddy Current

Zhou

Liu

Chen

2015

AMM

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This paper presents a flaw inspection method based on eddy current effect, by comparison of environment analysis and inspection methods for the high-speed train bogie surface flaw. It designed a testing physical prototype and a reasonable control system which was based on eddy current inspection bogie surface flaw, what’s more, it made use of restraining lift-off effect in testing two times, and the result of experiment indicated that method which tested bogie surface flaw was feasible and effective by digital monitor. The method will offer a guarantee for moving of the high-speed train safely and comfortably, and establish a little base to inspect interior flaw and research farther.

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“…These led to the development of non-contact testing methods, with air serving as the ambient or contact medium (Fang et al [4]). Usually, water is used as contact or ambient medium, due to its suitable impedance properties to many materials (Zhang et al [5], Jasiuniene et al [6], Mitri et al [7]). However, due to the large difference in impedance with air as the contact medium, most of the ultrasonic energy is reflected at the interface between the media (Sanabria et al [8]).…”

Section: Introductionmentioning

confidence: 99%

The Spec-Radiation Method as a Fast Alternative to the Re-Radiation Method for the Detection of Flaws in Wooden Particleboards

Schmelt¹,

Twiefel²

2020

Applied Sciences

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For real-time evaluation of non-destructive air-coupled ultrasonic testing of wood-based materials, efficient and reliable calculation methods from ultrasonic holography are essential. Presented here is the spec-radiation method as a fast alternative to the re-radiation method. The spec-radiation method offers a more accurate and up to 88% faster evaluation than the re-radiation method for the determination of flaws in particleboards. Flaws of sub-wavelength sizes can be identified and their shape and location can be determined with this method. The spec-radiation method produces a better reproduction of the sound field than the re-radiation method, especially in the area of the measuring plane.

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Comparison of continuous-wave (CW) and tone-burst (TB) excitation modes in vibro-acoustography: Application for the non-destructive imaging of flaws

Cited by 19 publications

References 26 publications

Piezoelectret-based hydrophone: an alternative device for vibro-acoustography

Piezoelectret-based hydrophone: an alternative device for vibro-acoustography

Intelligent Inspection of the High-Speed Train Bogie Flaw Based on Eddy Current

The Spec-Radiation Method as a Fast Alternative to the Re-Radiation Method for the Detection of Flaws in Wooden Particleboards

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