• Title/Summary/Keyword: Bolt clamped Langevin-type transducer

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Investigation of standing wave acoustic levitation with Bernoulli principle and bolt-clamped Langevin type ultrasonic transducer (베르누이 원리와 bolt-clamped Langevin type 초음파 진동자를 이용한 정상파 음파 공중부양의 탐구)

  • Park, Mincheol;Park, Doojae;Kim, Young H.
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.6
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    • pp.422-427
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    • 2018
  • The purpose of this study is to investigate the effect of acoustic radiation force on the standing wave acoustic levitation phenomenon, which is the levitation of small objects near the pressure node of the standing wave, using the Bernoulli principle. The source and scheme of the acoustic radiation force, which is the cause of the levitation, are conceptually explained through comparison with the graph of the acoustic radiation force versus the distance from the transducer. A series of experiments supporting this explanation was performed with a BLT(Bolt-clamped Langevin Type) ultrasonic transducer to confirm that the objects are floating near the pressure nodes and that it satisfies the condition for the standing wave formation when the object is levitating. Furthermore, the vertical alignment of floating objects, which is a characteristic of standing wave acoustic levitation phenomenon, could be explained.

Suggestion of an experimental method for optimization of flange point of a bolt-clamped Langevin-type ultrasonic transducer (볼트 체결형 란주반 초음파 트랜스듀서의 프렌지 포인트 최적화를 위한 실험적 방법 제안)

  • Kim, Jungsoon;Kim, Haeun;Kim, Moojoon
    • The Journal of the Acoustical Society of Korea
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    • v.40 no.4
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    • pp.270-277
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    • 2021
  • In the power ultrasound fields, the flange position for fixing the transducer is an important factor influencing on electro-mechanical efficiency of the transducer. We suggested a practical method that can determine the installation position of the flange for different resonance modes of the bolt-clamped type Langevin ultrasonic transducer. A semicircular wedge-shaped jig was manufactured and moved along the lateral surface of the transducer. The vibration characteristics were examined after a constant pressure was applied to the semicircular wedge-shaped jig. By observing the change of the input admittance of the transducer depending on the position of the pressure application, the optimum position for the flange installation could be determined. The resonant modes of the transducer were calculated by a Mason's equivalent circuit, and the particle velocity distribution for each resonance mode was calculated by a transmission line model. Since the optimum positions determined from an experimental result show a good correspondence with the node positions of the vibration modes calculated by the transmission line model, the validity of the suggested method was verified.

Variation in the Vibration Characteristics of a Piezoelectric Transducer due to Pre-pressure (예압에 따른 압전 변환기의 공진특성 변화)

  • Kim, Dae-Seung;Kim, Jin-Oh
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.1 s.106
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    • pp.89-100
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    • 2006
  • This paper presents an analytical approach to describe the variation in the vibration characteristics such as the natural frequency of a piezoelectric transducer under static pre-pressure. The transducer considered in this paper is a bolt-clamped Langevin-type transducer, which consists of a couple of piezoelectric discs, a couple of metal blocks for added mass effect, and a bolt to tighten them. A new analysis model for the transducer has been developed by taking into account the contact area between the piezoelectric ceramic disc and the metal block. The variation of the resonance frequency due to the pre-pressure has been calculated and compared with measured results reported earlier.

Analysis Model of a Piezoelectric Transducer with Incomplete Contact (압전 변환기의 내부 불완전 접촉을 고려한 해석 모델)

  • Kim, Dae-Seung;Kim, Jin-Oh
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.864-868
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    • 2005
  • This paper develops an analysis model of a piezoelectric transducer. The transducer considered in this paper is a bolt-clamped Langevin-type transducer, which consists of a couple of piezoelectric discs, a couple of metal blocks for added mass effect, and a bolt to tighten them. A new analytical model for the transducer has been developed by taking into account the contact area between the piezoelectric ceramic and the metal block. The analysis model is verified by calculating the variations of the resonance frequency due to the contact area and comparing them with reported experimental results.

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Variation In the Vibration Characteristics of Piezoelectric Transducers due to Pre-Pressure (예압에 따른 압전 변환기의 공진 특성)

  • Kim, Dae-Seung;Kim, Jin-Oh
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.484-487
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    • 2005
  • This paper presents an analytical approach to describe the variation in the vibration characteristics such as the natural frequency of a piezoelectric transducer under static pre-pressure. The transducer considered in this paper is a bolt clamped Langevin type transducer, which consists of a couple of piezoelectric discs, a couple of metal blocks for added mass effect, and a bolt to tighten them. A new analysis model for the transducer has been developed by taking into account the contact area between the piezoelectric ceramic and the metal block. The variation of the resonance frequency due to the pre-pressure has been calculated compared with other results.

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Finite Element Analysis for the Development of Bone Surgery Piezoelectric Ultrasonic Medical Device and its Experimental Verification (골수술용 압전형 초음파 의료기기 개발을 위한 유한요소해석 및 이의 실험적 검증)

  • Song, Tae-Ha;Lee, Jung-Ho;Choi, Jong Kyun;Lee, Hee Won
    • Journal of Biomedical Engineering Research
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    • v.43 no.5
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    • pp.319-330
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    • 2022
  • In this study, the optimal driving frequency was derived through finite element analysis (FEA) to optimize the developed piezoelectric ultrasonic medical devices(PUMD) for bone surgery. The core of the PUMD is the piezoelectric ceramic (PZT), which is a vibrator that generates vibration energy. The piezoelectric ceramic shows the maximum current value with respect to the input voltage at the resonance frequency, which generates the maximum mechanical vibration. In the past, various studies have been conducted related to the analysis of PUMD, but most of the research so far has been limited to free vibration analysis. However, in order to derive the accurate resonant frequency, the initial stress generated by bolt tightening in the bolt-clamped Langevin type transducer (BLT) must be considered. In this study, after designing a PUMD, the driving performance according to the bolt tightening value was analyzed through FEA, and this was experimentally verified. First, the resonance mode and frequency response were confirmed through modal and harmonic analysis at 20-40 kHz, which is known as the optimal driving frequency band of PUMD for bone surgery. In addition, the design of the PUMD was confirmed by checking the mechanical behavior of the tip and the piezoelectric ceramic at the resonant frequency. Consequentially, the characteristic evaluation was performed, and it was confirmed that the resonant frequency result derived through the FEA was reasonable. Through this study, we presented a more rational FEA method than before for BLT transducers. We expect that this will shorten the time and cost of developing a PUMD, and will enable the development of more stable and high-quality products.

Development of a High-power Ultrasonic System for Sonochemistry Reaction (음향화학 반응용 강력초음파 개발)

  • Lee, Yang-Lae;Kim, Hyun-Se;Baek, Min-Hyuck
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.142-148
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    • 2013
  • High-power ultrasonic promotes a chemical reaction by its own energy, thus it has been used for sonochemistry applications. For example, it has been mostly used for mixing, reaction catalyst, dispersion and disintegration. High-power ultrasonic transducer is made with structure based on a Bolt-clamped Langevin type Transducer (BLT), But it has difficulty in the development because degradation of piezoelectric ceramic by the heat generation of BLT. In this study, for a development of the transducer of 25 kHz and 1000 W used in sonochemistry and industrial cleaning, BLT with a hole in its center and tubular type waveguide of the transducer were designed based on finite element method (FEM). The transducer was fabricated based on the design parameter, and the impedance characteristics are measured experimentally and compared with the numerical results.

A High power and Precision Ultrasonic Linear Motor with Multi-support Mechanism (다점 지지 고출력 고정도 초음파 모터)

  • Lee S.K.;Yun C.H.;Lee J.Y.;Cha H.R.;Kim W.K.;Kang J.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.151-152
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    • 2006
  • Nowadays, great attention has been shown to the question of ultrasonic linear motor for accomplishing the high positioning accuracy and high driving force in the semiconductor and optical industry. Ultrasonic linear motors have many advantages such as simple structure, quick response, ability to maintain position without energy consumption, and electromagnetic effect. And BLT has attracted attention to accomplish large vibration amplitude and large mechanical force. Authors designed and developed the new type of ultra sonic linear motor with multi support mechanism, achieved 75N of output force and 0.45m/s of velocity.

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