Antisymmetric Flexural Modes Propagating along Apex of Piezoelectric Wedges

Wang, Wen-Chih; Yang, Che‐Hua

doi:10.1143/jjap.46.5939

Cited by 8 publications

(3 citation statements)

References 14 publications

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“…Although the acoustic waves propagating at the tip of an ideal infinite wedge waveguide is dispersionless, the weak Mei and Friend, Mechanical Engineering Reviews, Vol.7, No.1 (2020) [DOI: 10.1299/mer.19-00402] dispersion still attributes to a number of factors. As a result, in later years, wedge waves can be used in non-destructive testing (Wang et al, 2007;Liu et al, 2010), as modifying the geometry of the wedge can apparently change the dispersion relation. And sometimes the dispersion is intentionally introduced to produce nonlinear effects as needed (Krylov et al, 1992;Krylov et al, 1993;Mayer et al, 1997;Mayer et al, 2009).…”

Section: Wedgementioning

confidence: 99%

A review: controlling the propagation of surface acoustic waves via waveguides for potential use in acoustofluidics

Mei

Friend

2020

Mechanical Engineering Reviews

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This paper presents a review of waveguides on lithium niobate for surface acoustic waves (SAWs), including in particular the classic literature on the topic with the intent of renewing interest in them in the context of potential applications in the burgeoning discipline of micro to nano-scale acoustofluidics. From the fundamentals of the piezoelectric effect we describe interdigital electrodes and how they generate acoustic waves, consider focusing interdigital electrodes as a simple means of laterally confining the acoustic energy propagating across a substrate, and then quickly move to waveguiding structures that provide confinement by defining either a region of slow wave velocity or a physically isolated structure. The ability to steer acoustic waves using these waveguides is considered. The many analytical, computational, and experimental tools devised by past investigators to design them are discussed in detail, as are the relative advantages and disadvantages of the waveguide designs considered over the years.The most popular materials that are used to make SAW devices include quartz, lithium tantalate (LT) LiTaO 3 and lithium niobate (LN) LiNbO 3 . Others include gallium arsenide (GaAs), cadmium sulfide (CdS), zinc oxide (ZnO), lithium tetraborate (Li 2 B 4 O 7 ), and lanthanum gallium silicate (La 3 Ga 5 SiO 12 ) (Thurston et al., 1998). Due to the crystalline structure of these materials, the type of wave generated is strongly dependent on the choice and orientation of the material as discussed above. Lithium niobate has been the preferred material for devices requiring high efficiency, as it possesses a relatively large electromechanical coupling coefficient open-circuit) and v m is the SAW velocity along a short-circuited surface. Of the various cuts possible, the 131 • Y-rotated cut for X-propagating SAW in LN was found to have the highest electromechanical coupling coefficient for SAW (Slobodnik et al., 1970), relative to other cuts in LN and other choices of single-crystal piezoelectric media. In 1976, Shibayama et al. conducted experiments to determine the optimum rotated Y-cut of LN to generate "true" SAWs and concluded that the 127.86 • Y-rotated choice for X-propagating SAW in lithium niobate (128 • YX LN) reduced the generation of other parasitic waves and retained most of the electromechanical coupling and low insertion loss observed in the 131 • Y-rotated cut of LN. Generating SAW on lithium niobateInterdigital transducers are one of the most widely used devices that generate and detect SAWs. The first and simplest IDTs (White et al., 1965) consisted of straight rectangular metal bars-fingers-deposited on the surface of a piezoelectric substrate. Alternately connected on their end to common electrodes or bus bars, the fingers appear as depicted in Fig. 1. An array of electric fields of alternating direction is created between the transducer finger pairs, and thus in turn induces alternating regions of compression and tension in the substrate. Each finger pair therefore produces displacemen...

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Section: Wedgementioning

confidence: 99%

A review: controlling the propagation of surface acoustic waves via waveguides for potential use in acoustofluidics

Mei

Friend

2020

Mechanical Engineering Reviews

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“…Jia and coworkers 9,10) first used the laser ultrasound technique to study the propagation characteristic of wedge waves. Yang and coworkers 11,12) investigated the influences of the wedge shape and the coating on the dispersion of wedge waves and the propagation characteristics of wedge waves along the apex of piezoelectric wedges. Otherwise, localized acoustic surface waves propagating along an immersed V-groove 13) have been researched recently.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, they often focused on the propagation of wedge waves on the wedge tip 14) and the influence of wedge shape, coatings, and truncation on the dispersion of wedge waves. 11,12) Apart from the recent work, no attention has been paid to the understanding of mode transformation and energy attenuation of acoustic waves propagating on the wedge surface. In this study, both experimental work and FEM are used to investigate the mode transformation and energy attenuation of acoustic waves as the propagating line is scanned away from the tip.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Mode Transformation and Energy Attenuation of Wedge Waves Generated by Laser Ultrasound Technique

Jia

Shen

Yuan

et al. 2012

Jpn. J. Appl. Phys.

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This paper focuses on a frequency-weighted hybrid adaptive control with application to simultaneous precision positioning and vibration suppression of smart composite structures. Following the introduction of the structure and materials system of an active composite panel (ACP) with a surface-mounted and two embedded piezoelectric ceramic patches, the sensor selection for the purpose of precision positioning or vibration control is discussed, and the function assignment of a laser displacement sensor as well as the embedded piezoelectric sensor is determined for the ACP. The frequency-weighted hybrid adaptive control approach is then developed. The approach consists of an adaptive feedforward position controller for precision positioning, an adaptive feedforward vibration controller for vibration suppression as well as an adaptive feedback controller for both precision positioning and vibration suppression. The frequency-weighted filters introduced in the approach realize the signal fusion of the two sensors. Finally, experiments are also performed for harmonic disturbances at the first two natural frequencies of the ACP and a random disturbance for both cases of with/without the adaptive feedforward vibration controller, demonstrating that the frequency-weighted hybrid adaptive control approach can provide satisfactory precision positioning and vibration suppression in both cases, and that better position accuracy can be achieved if the adaptive feedforward vibration controller is also employed.

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