Abstract
A novel effective vibrational mode was discovered in the conventional transducer with an array of orthogonal (square) regular piezoelectric rods in 1-3 piezocomposite, containing the damping backing and front matching layers. The operational resonance in the structure was determined as the Surface Acoustic Wave (SAW) on the backing boundary excited by the adjacent piezo-rods, with its frequency typically near 3 times lower the fundamental half-lambda conventional piezocomposite resonance. Pulse-echo sensitivity and transmitting sound pressure level (SPL) in air showed that the signal strength is roughly comparable to the industrial similar air transducers at the frequency range 100–700 kHz, where at these frequencies the lateral and longitudinal piezoelement dimensions in the conventional transducer design are typically close to each other causing interference with unwanted coupling modes. As was determined theoretically and proved in experiments, the backing SAW resonance effect in the transducer performance is inherent just to the regular periodic 1-3 piezocomposite structure and does occur neither with randomly located/oriented piezo-rods nor in the homogeneous piezo-plate at least with the same lateral cross-section as the connected to it backing. The purpose of the article is to investigate a newly discovered operational vibrational mode of a SAW type in 1-3 regular piezocomposite, other than piezoelectric resonance. The investigated phenomena can improve the transceiver sensitivity and bandwidth, providing lower drive voltage and smaller and lighter weight ultrasonic transducers. Based on the piezocomposites with thickness’ 1–1.5 mm (rod resonance near 2–3 MHz), pillar width 0.2–0.8 mm, kerf width 0.1–0.4 mm, the transceivers with an operating frequency from 140 kHz to 650 kHz were designed and fabricated with a conventional backing of a mixture of high-density tungsten powder and epoxy and a matching layer of a mixture of low-density glass bubbles and epoxy. Experimental evaluation of their acoustical performance showed expected characteristics suitable for practical applications.
Highlights
The 1-3 piezocomposite consists of an array of parallel piezoelectric rods embedded in a polymer matrix with electrode layers on the top and bottom surfaces and incorporates epoxy (‘ies) for bond-lines, backing, and matching layers
Acoustics 2020, 2, 8 common piezoelectric materials used in ultrasonic transducers are piezoceramics, such as lead zirconate titanate (Pb(Zr,Ti)O3, or PZT), and piezocomposites based on it, which possess relatively strong piezoelectric effect [1,2,3]
First of all, rigid piezo-rod-toThe Rayleigh Surface Acoustic Wave (SAW) resonance discovered in the piezocomposite backing boundary is a powerful backing bonding and regular periodic structure array, at least with several adjacent piezo-rods
Summary
The 1-3 piezocomposite consists of an array of parallel piezoelectric rods embedded in a polymer matrix with electrode layers on the top and bottom surfaces and incorporates epoxy (‘ies) for bond-lines, backing, and matching layers. It improves mechanical and ultrasonic performance compared to a baseline traditional design with a homogeneous piezoelectric plate, for example, providing broader bandwidth, shorter pulse, lower Q-factor, and clear spectra with suppressed planar unwanted modes. A voltage pulse is applied between the front and back surfaces of the piezoceramic rods of a 1-3 piezocomposite to excite a mechanical expansion thickness resonance (rod length) of the piezoelectric plate Acoustics 2020, 2, 8 common piezoelectric materials used in ultrasonic transducers are piezoceramics, such as lead zirconate titanate (Pb(Zr,Ti)O3 , or PZT), and piezocomposites based on it, which possess relatively strong piezoelectric effect [1,2,3].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
