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12 pages, 5863 KB

Open AccessArticle

Design and Fabrication of a High-Sensitivity and Wideband Cymbal Hydrophone

by Donghyun Kim and Yongrae Roh

Sensors 2023, 23(22), 9086; https://doi.org/10.3390/s23229086 - 10 Nov 2023

Cited by 4 | Viewed by 1958

So far, cymbal transducers have been developed primarily for transmitting purposes, and even when used for receiving, the focus has been mostly on improving the receiving sensitivity. In this study, we developed a cymbal hydrophone with a higher sensitivity and a wider bandwidth [...] Read more.

So far, cymbal transducers have been developed primarily for transmitting purposes, and even when used for receiving, the focus has been mostly on improving the receiving sensitivity. In this study, we developed a cymbal hydrophone with a higher sensitivity and a wider bandwidth than other existing hydrophones. First, the initial structure of the cymbal hydrophone was established, and then the effects of structural variables on the hydrophone’s performance were analyzed using the finite element method. Based on the analysis results, the structure having the highest sensitivity and widest bandwidth, with a receiving voltage sensitivity level above a certain threshold, was derived using optimal design techniques. A prototype of the cymbal hydrophone with the designed structure was fabricated, and its performance was measured, validating the effectiveness of the design by comparing the measurement results with the design values. The developed cymbal hydrophone is expected to be utilized in various underwater precision measurements, as it possesses a significantly broader reception frequency bandwidth when compared with other hydrophones used for the same purpose. Full article

(This article belongs to the Special Issue Flexible Piezoelectric Transducers and Applications Based on Sensors and Actuators)

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18 pages, 5251 KB

Open AccessArticle

Research on Stacked Piezoelectric Cymbal Vibrator

by Xinhu Liu, Yajun Zheng, Yanming Guo, Ningdong Hu and Hongping Hu

Micromachines 2023, 14(11), 2039; https://doi.org/10.3390/mi14112039 - 31 Oct 2023

Cited by 2 | Viewed by 1684

Abstract

As demand for haptic feedback increases, piezoelectric materials have become one of the best candidate materials due to their small size, high electromechanical coupling coefficient, and fast response. A stacked piezoelectric cymbal vibrator is proposed based on the common cymbal-type transducer, which is [...] Read more.

As demand for haptic feedback increases, piezoelectric materials have become one of the best candidate materials due to their small size, high electromechanical coupling coefficient, and fast response. A stacked piezoelectric cymbal vibrator is proposed based on the common cymbal-type transducer, which is composed of a piezoelectric stack to drive and a cymbal disk to amplify displacement. A coupling theoretical model between the piezoelectric stack and the cymbal-type structure is established. The longitudinal and radial displacements of the stacked piezoelectric cymbal vibrator are calculated in the low frequency range (<1000 Hz) by the theoretical model and the finite element method. The theoretical and numerical results are in good agreement. The results show that the radial displacement can be converted into longitudinal displacement and then effectively amplified by the cymbal disk with an amplification ratio of 30. The feature is conducive to its widespread application in the field of consumer electronics. Full article

(This article belongs to the Special Issue Piezoelectric Materials, Devices and Systems)

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15 pages, 6279 KB

Open AccessArticle

Development of Multilayer Transducer and Omnidirectional Reflection Model for Active Reflection Control

by Beom Hoon Park, Han Bin Choi, Hee-Seon Seo, Yub Je, Hak Yi and Kwan Kyu Park

Sensors 2023, 23(1), 521; https://doi.org/10.3390/s23010521 - 3 Jan 2023

Cited by 1 | Viewed by 3038

Abstract

Underwater detection is accomplished using an underwater ultrasonic sensor, sound navigation and ranging (SONAR). Stealth to avoid detection by SONAR plays a major role in modern underwater warfare. In this study, we propose a smart skin that avoids detection by SONAR via controlling [...] Read more.

Underwater detection is accomplished using an underwater ultrasonic sensor, sound navigation and ranging (SONAR). Stealth to avoid detection by SONAR plays a major role in modern underwater warfare. In this study, we propose a smart skin that avoids detection by SONAR via controlling the signal reflected from an unmanned underwater vehicle (UUV). The smart skin is a multilayer transducer composed of an acoustic window, a double-layer receiver, and a single-layer transmitter. It separates the incident signal from the reflected signal from outside through the time-delay separation method and cancels the reflected wave from the phase-shifted transmission sound. The characteristics of the receiving and transmitting sensors were analyzed using a finite element analysis. Three types of devices were compared in the design of the sensors. Polyvinylidene fluoride (PVDF), which had little effect on the transmitted sound, was selected as the receiving sensor. A stacked piezoelectric transducer with high sensitivity compared to a cymbal transducer was used as the transmitter. The active reflection control system was modeled and verified using 2D 360° reflection experiments. The stealth effect that could be achieved by applying a smart skin to a UUV was presented through an active reflection–control omnidirectional reflection model. Full article

(This article belongs to the Special Issue The Development of Piezoelectric Sensors and Actuators)

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14 pages, 5245 KB

Open AccessArticle

Equivalent Circuit to Analyze the Transmitting Characteristics of a Cymbal Array

by Hayeong Shim, Kyungseop Kim, Heeseon Seo and Yongrae Roh

Sensors 2022, 22(22), 8743; https://doi.org/10.3390/s22228743 - 12 Nov 2022

Cited by 5 | Viewed by 2477

Abstract

A cymbal transducer has a simple structure consisting of a piezoceramic disk and metallic caps and has broadband characteristics when built as an array. The finite element method (FEM) is generally used to analyze the characteristics of acoustic transducers. However, the FEM requires [...] Read more.

A cymbal transducer has a simple structure consisting of a piezoceramic disk and metallic caps and has broadband characteristics when built as an array. The finite element method (FEM) is generally used to analyze the characteristics of acoustic transducers. However, the FEM requires a longer analysis time as the model becomes larger, which makes it limited and less efficient for analyzing the cymbal array. In this study, a new equivalent circuit with higher efficiency and accuracy, comparable to that of the FEM, was proposed to analyze the performance of cymbal arrays. The equivalent circuit for the array was constructed by connecting the equivalent circuits of individual cymbal transducers in parallel with a radiation impedance matrix that included both the self- and mutual radiation characteristics of the array. The validity of the new equivalent circuit was verified by measuring the transmitting voltage response of a cymbal array specimen and comparing it with that calculated using the circuit. The comparison confirmed the efficiency of the equivalent circuit in analyzing the characteristics of the cymbal array. The proposed equivalent circuit can facilitate the design of a large array of cymbal transducers. Full article

(This article belongs to the Special Issue The Development of Piezoelectric Sensors and Actuators)

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11 pages, 3554 KB

Open AccessArticle

Selection of a Potting Material and Method for Broadband Underwater Cymbal Arrays

by Wenbo Wang, Hayeong Shim and Yongrae Roh

Sensors 2022, 22(21), 8324; https://doi.org/10.3390/s22218324 - 30 Oct 2022

Viewed by 2803

Abstract

Cymbal transducers are often used in arrays for underwater communication and detection systems. The working environment of a cymbal array is underwater; therefore, waterproofing, salt-corrosion prevention, and impact resistance are necessary for stable operation of the array. Hence, we simulated potting a cymbal [...] Read more.

Cymbal transducers are often used in arrays for underwater communication and detection systems. The working environment of a cymbal array is underwater; therefore, waterproofing, salt-corrosion prevention, and impact resistance are necessary for stable operation of the array. Hence, we simulated potting a cymbal array with 15 different rubber and epoxy materials available in the market, using the finite element method, and analyzed their effect on the transmitting voltage response spectrum of the array. From the analysis results, we selected the material that would achieve the widest frequency bandwidth, while preserving the structural stability of the array. A potting method corresponding to the selected material was suggested as well. This study provides guidelines for the selection of a potting material for use in underwater transducer arrays. Full article

(This article belongs to the Special Issue The Development of Piezoelectric Sensors and Actuators)

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17 pages, 8508 KB

Open AccessArticle

Development of a Dual-Layer Structure for Cymbal Transducer Arrays to Achieve a Wider Bandwidth

by Jahnavi Mudiyala, Hayeong Shim, Donghyun Kim and Yongrae Roh

Sensors 2022, 22(17), 6614; https://doi.org/10.3390/s22176614 - 1 Sep 2022

Cited by 10 | Viewed by 2766

Abstract

Cymbal transducers are typically grouped and arranged in planar arrays. For projector arrays, a wide bandwidth on the transmitting voltage response (TVR) spectrum is required for better underwater communication and data transmission within a short time. The purpose of this study is to [...] Read more.

Cymbal transducers are typically grouped and arranged in planar arrays. For projector arrays, a wide bandwidth on the transmitting voltage response (TVR) spectrum is required for better underwater communication and data transmission within a short time. The purpose of this study is to develop a wideband cymbal array by controlling the center-to-center (CTC) spacing between the cymbal transducers in the array. In the practical design of the array, due to the arrangement of elements in one layer, the minimum CTC spacing between the cymbals is constrained to the diameter of the cymbals in use. To overcome this limitation, we propose a new dual-layer array structure. Finite element analysis of the cymbal array showed that the bandwidth was generally inversely proportional to the CTC spacing. We explained the mechanism of this relationship using a theoretical analysis of the mutual radiation impedance between the cymbals in the array. Subsequently, we identified the optimum CTC spacing to achieve the widest possible bandwidth for the cymbal array. The validity of the wideband array design was verified through the fabrication and characterization of prototype arrays. We confirmed that the two-layered arrangement could significantly widen the bandwidth of the cymbal array while maintaining the TVR above a specified level. Full article

(This article belongs to the Special Issue Development, Investigation and Application of Acoustic Sensors)

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11 pages, 2726 KB

Open AccessArticle

Design of a Broadband Array Pattern of Underwater Cymbal Transducers

by Donghyun Kim, Hayeong Shim, Changmin Oh, Kyungseop Kim, Heeseon Seo and Yongrae Roh

Sensors 2021, 21(18), 6119; https://doi.org/10.3390/s21186119 - 12 Sep 2021

Cited by 7 | Viewed by 3232

Abstract

Cymbal transducers are frequently used as an array rather than a single element because of their high quality factor and low energy conversion efficiency. When used as an array, cymbal transducers are likely to have a big change in their frequency characteristics due [...] Read more.

Cymbal transducers are frequently used as an array rather than a single element because of their high quality factor and low energy conversion efficiency. When used as an array, cymbal transducers are likely to have a big change in their frequency characteristics due to the interaction with neighboring elements. In this study, we designed an array pattern of cymbal transducers to achieve a wide frequency bandwidth using this property. First, cymbal transducers with specific center frequencies were designed. Next, a 2 × 2 planar array was constructed with the designed transducers, where dielectric polarity directions of the transducers were divided into two cases (i.e., same and different). For the array, the effect of the difference in the center frequencies and the spacing between the transducers on the acoustic characteristics of the entire array was analyzed. Based on the results, the structural pattern of the array was optimized to have the maximum fractional bandwidth while maintaining the transmitting voltage response over a given requirement. The design validity was verified by making cymbal array prototypes, followed by measuring their performances and comparing them with that of the design. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 8295 KB

Open AccessArticle

Design and Fabrication of a Wideband Cymbal Transducer for Underwater Sensor Networks

by Hayeong Shim and Yongrae Roh

Sensors 2019, 19(21), 4659; https://doi.org/10.3390/s19214659 - 27 Oct 2019

Cited by 22 | Viewed by 5198

Abstract

Cymbal transducers are characterized by a high mechanical quality factor and low power efficiency. The research conducted so far on cymbal transducers has focused on improving the power efficiency and structural stability, but modern underwater sensor network systems need transducers to have a [...] Read more.

Cymbal transducers are characterized by a high mechanical quality factor and low power efficiency. The research conducted so far on cymbal transducers has focused on improving the power efficiency and structural stability, but modern underwater sensor network systems need transducers to have a wide frequency bandwidth as well. In this study, a wideband cymbal transducer was designed to fill that need. First, the effect of various structural parameters on the performance of the cymbal transducer was analyzed with emphasis on the bandwidth using the finite element method. Based on the analysis results, the structure of the cymbal transducer was optimized to have the widest possible bandwidth while maintaining its transmitting voltage response (TVR) level over a typical power requirement as well. The validity of the design was verified by fabricating a prototype of the optimized cymbal transducer and comparing its measured performance with the design. Full article

(This article belongs to the Special Issue Development of Piezoelectric Sensors and Actuators)

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11 pages, 4546 KB

Open AccessArticle

Design and Analysis of Two Piezoelectric Cymbal Transducers with Metal Ring and Add Mass

by Wenjie Wang, Weihao Shi, Peter Thomas and Mingsui Yang

Sensors 2019, 19(1), 137; https://doi.org/10.3390/s19010137 - 2 Jan 2019

Cited by 10 | Viewed by 5129

Abstract

Based on traditional sandwich structure, two piezoelectric transducers were designed to meet the strict underwater application backgrounds such as high pressure, corrosion resistance, and high strength. Both transducers integrated most of previous researches while one transducer has a multilayer cavity structure which is [...] Read more.

Based on traditional sandwich structure, two piezoelectric transducers were designed to meet the strict underwater application backgrounds such as high pressure, corrosion resistance, and high strength. Both transducers integrated most of previous researches while one transducer has a multilayer cavity structure which is different from the other structure and previous transducer structures. After a detailed simulation analysis of every structural parameter, key parameters were pointed out to have an obvious influence on its performance. Then, two models were constructed and compared with chosen sets of geometry parameters and manufacturing process, which can also provide a reference for low-frequency transducer design. The simulation results and experimental results of our transducers show a good consistency which indicates the cavity structure can reduce the resonance frequency. Full article

(This article belongs to the Special Issue Underwater Sensor Networks: Applications, Advances and Challenges)

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