Abstract This paper investigates the impact of different matching layers on ultrasonic transducers’ performance. Matching are mostly used to solve acoustic impedance problem between piezoelectric element and test specimen. To design good layers, we merged metal–polymer mass–spring systems. Their thickness was also optimized using quarter-wavelength approach. Silver, alumina, copper served as ma...

The paper is devoted to the experimental investigation of the statistical characteristics of the grid-generated turbulence produced in a wind tunnel. Ultrasonic time-of-flight method using dual transducers is utilized to develop a methodology for determination of the correlation functions of turbulent velocity and sound speed fluctuations. The ultrasonic flowmeter equation is considered in the ...

Ultrasonic phased arrays are an emerging technology in nondestructive evaluation (NDE) applications. A phased array is a multi-element piezo-electric device whose elements are individually excited by electric pulses at programmed delay times [1]. Such a delay scheme allows electronically controlled dynamic beam control. One of the advantages of using phased arrays in NDE applications over conve...

Capacitive diaphragm MEMS ultrasonic transducers are of great interest because they offer wide bandwidth and ready integration into arrays. However, fragility of these transducers is a significant barrier to their application. In this talk, we report on robust transducers which have been fabricated using the MUMPS process. The transducer design has been optimized to minimize stray capacitance b...

A simple fabrication technique was developed to produce high frequency (100 MHz) self-focused single element transducers with sputtered zinc oxide (ZnO) crystal films. This technique requires the sputtering of a ZnO film directly onto a curved backing substrate. Transducers were fabricated by sputtering an 18 μm thick ZnO layer on 2 mm diameter aluminum rods with ends shaped and polished to pro...

Thick (> 40μm) ceramic films as piezoelectric ultrasonic transducers (UTs) have been successfully deposited on metallic and graphite/epoxy composite substrates by a spray technique. The characteristics of these UTs are that they (1) can be integrated directly onto the desired planar or curved substrates; (2) may not need couplant; (3) can operate in the transmission and pulse/echo modes with a ...

The overall performance of sandwiched ultrasonic transducers can be substantially degraded due to defects. Model-based diagnosis can be an attractive technique for monitoring the performance of sandwiched ultrasonic transducers. Using electromechanical models of the transducer, most parameters of the system can be determined based on measurements of electrical input quantities only. This contri...