Capacitive and piezoelectric air-coupled transducers for resonant ultrasonic inspection

Schindel, D.W.; Hutchins, David A.; Grandia, Willem

doi:10.1016/0041-624x(96)00063-7

Cited by 52 publications

(15 citation statements)

References 18 publications

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“…By using this broadband response, the broadband impulse source was observed. 7) Defect depths estimation by measuring the transverse resonances of polymer-composite-, 8) metal-9) and multilayeredplates 10) were also achieved by the normal incidence of air-coupled ultrasounds with broadband response. On the other hand, the piezoelectric composite transducer consists of piezoelectric pillars embedded in polymer matrix.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigations of Transmission Coefficients of Longitudinal Waves through Metal Plates Immersed in Air for Uses of Air Coupled Ultrasounds

et al. 2008

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Theoretical and experimental investigations of transmission coefficients of longitudinal waves through metal plates immersed in air have been carried out for noncontact and nondestructive testing (NDT) of metal plates. Transmission coefficients through metal plates in water and through polymer plates in air have also been shown for comparisons. Theoretical relations between the transmission coefficients and the Lamb wave dispersions were described. It was confirmed that the transmission coefficients took high values when the Lamb waves were generated without exception. Quantitative evaluations for the transmission coefficients were investigated for the use of the air-coupled ultrasounds. The experimental verifications were carried out using 1-, 3-, and 5-mm-thick aluminum plates. The experimental results of the transmission coefficients were in fairly good agreement with the theoretical predictions.

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Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigations of Transmission Coefficients of Longitudinal Waves through Metal Plates Immersed in Air for Uses of Air Coupled Ultrasounds

et al. 2008

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“…al. [46] observed that higher transmission can be obtained at the position of the defects when the center frequency of the capacitive transducers where changed according to depth of the defect. This phenomenon was explained by the broadband nature of the signals generated by the capacitive transducers.…”

Section: Bright Spot In Through Transmissionmentioning

confidence: 81%

<title>Air-coupled ultrasonic measurements in composites</title>

2005

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“…For actuating applications, ultrasound is utilized in industrial cleaning, material soldering (Parrini, 2001), and medical diagnoses and therapies (Shung and Zipparo, 1996). The piezoelectric transducer (Schindel et al, 1996) was previously the major device for generating ultrasound when ultrasound was applied for solid material NDE. Piezoelectric devices are preferred as the characteristic impedance of piezoelectric materials is the same order of magnitude as that of the solids.…”

Section: Introductionmentioning

confidence: 99%

Surface micromachined capacitive ultrasonic transducer for underwater imaging

Liu¹,

Chen²

2007

Journal of the Chinese Institute of Engineers

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This study presents the primary design, fabrication process and device measurement of a Capacitive Micromachined Ultrasonic Transducer (CMUT) for underwater acoustic imaging. Theoretical analysis and computer simulations of the CMUT are performed. The CMUT fabrication uses the full surface micromachining techniques of the Micro Electro Mechanical System (MEMS). These techniques are Low Pressure Chemical Vapor Deposition (LPCVD), photolithography, Reactive Ion Etching System (RIE) dry etching, sacrificial layer wet etching, metal thermal evaporation coating and Plasma-Enhanced Chemical Vapor Deposition (PECVD). Several important issues regarding fabrication are discussed. The measured input impedance of the CMUT is in agreement with the theoretical prediction. The received signal has a 35 dB signal-to-noise ratio indicating that practical applications of the immersion CMUT are feasible and that the radiation pattern measurement of the CMUT array has good beamforming characteristics for underwater imaging.

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Capacitive and piezoelectric air-coupled transducers for resonant ultrasonic inspection

Cited by 52 publications

References 18 publications

Theoretical and Experimental Investigations of Transmission Coefficients of Longitudinal Waves through Metal Plates Immersed in Air for Uses of Air Coupled Ultrasounds

Theoretical and Experimental Investigations of Transmission Coefficients of Longitudinal Waves through Metal Plates Immersed in Air for Uses of Air Coupled Ultrasounds

<title>Air-coupled ultrasonic measurements in composites</title>

Surface micromachined capacitive ultrasonic transducer for underwater imaging

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