• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.728-731
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• 2003

This paper deals with a flat type ultrasonic motor, which uses a longitudinal-bending multi mode vibrator of rectangular form. A linear ultrasonic motor was designed by combination of the first longitudinal and eighth bending mode, and the motor consisted of a straight aluminum alloy bar bonded with piezoelectric ceramic elements as a driving element. The geometrical dimensions of the rectangular aluminum vibrator were determined by Euler-Bernoulli theory ANSYS was used to analyze the resonance frequency and the displacement of the stator vibrator. The resonance frequency of the motor provides the elliptical motion. and ANSYS was used to analyze elliptical motion and elliptical trajectory of stator vibrator when thickness of piezoelectric ceramics was varied respectively 0.763, 1.526, 2.289[mm] and width of stator vibrator was varied respectively 16, 12, 8, 4[mm]. When thickness of piezoelectric ceramics was decreased, the displacement of the stator vibrator was increased. And when width of stator vibrator was decreased, the displacement of the stator vibrator was increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.269-272
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• 1990

This paper introduces a technique of shifting the resonant frequency and of depressing the spurious modes in the composite piezoelectric vibrator laminated in the order of piezoelectric vibrator/thin insulator/piezoelectric vibrator, whose vibrators have the the same sizes and the same properties, respectively. The composite vibrator has shown the characteristics that the fundermental resonant frequency has decreased and spurious modes have depressed with increase of the capacitance of the inserted insulator. And the frequency characteristics of the composite vibrator without insulator have been nearly the same as those of each vibrator.

• Tribology and Lubricants
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• 제27권6호
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• pp.332-337
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• 2011

The object of this experimental study is to investigate influences of vibrator amplitude on clamping force in vibration for bolted joint. The experiment is that change the vibrator amplitude to check clamping force. also the friction coefficient calculated by equation to use an obtained in experiments. The main purpose of generation vibrations is decreasing the clamping force dispersion. also If vibration occurs while tightening the bolt is reduced coefficient of friction. In this paper, In experiments to measure the clamping force before vibrator's amplitude changing. Vibrator's amplitude changes to 5.5mm from 4.4mm. As a result, under various vibration condition, relationship of clamping force and Vibrator amplitude.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.75-83
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• 2007

Elasticity is an important physical property of biological tissues. Differences in elasticity can help facilitate the diagnosis of tumors and their extent. Magnetic Resonance Elastography (MRE) tries to visualize images of tissue elasticity by externally applying shear stress on the surface of an imaging object. Applied shear stress induces internal displacements that can be measured from MR phase images. In order to conduct MRE imaging experiments, we need to first develop a vibrator. We found that there does not exist enough technical information to design the MRE vibrator. In this paper, we describe the theory, design and construction of an MRE vibrator. We report the performance of the developed vibrator using two different test methods. We found that the vibrator successfully induces enough internal displacements that can be imaged using an MRI scanner. We suggest future studies of numerous MRE imaging experiments using the vibrator.

• 대한전자공학회논문지
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• 제13권6호
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• pp.1-6
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• 1976

탄성파 지연선의 진동자에서 전단과 지연매질사이의 접착제의 두께를 고려하여 변환손실을 계산하는 방법을 제안하며, 수치계산결과 접착제의 두께가 진동자 두께의 1/100정도 이하로 하여야 하며 전극의 두께가 진동자 두께의 1/10정도 될 때 중심주파수의 이동이 생진다. 접착제의 두께를 진동자와 거의 같거나 그 이상으로 하면 주파수 대역폭에서 현상이 점점 커지게 된다. In this paper, the methode of calculating conversion loss is proposed by considering the thickness of bonding medium between electrode and delay material in the vibrator of Elastic delay lines. As the result of computations using digital computer, it is shown that the thickness of bonding medium must be less than about 1/100 of the thickness of vibrator and when the thickness of electrode is about 1110 of vibrator, the center fnequency is shifted. When the thickness of bonding medium is equal to or more than the thickness of vibrator, the 리uctuations in frequency Bandwidth become larger and larger.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.631-636
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• 2009

This paper presents design and analysis of ultrasonic vibrator featuring the piezoelectric actuator. After describing a geometric configuration of the proposed vibrator, an analytical model of the ultrasonic vibrator is formulated by adopting liquid film pattern theory and wave theory. The dynamic analysis and geometric optimization are then undertaken using a software ANSYS. The optimization is performed by taking the amplitude of the tip displacement as an objective function. The fluid flow characteristics of the proposed vibrator are analyzed by taking three different fluids: water, silicon oil and ethylene-glycol. This is achieved using a software FLUENT.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.601-604
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• 2002

In this paper bolt-tightened Langevin type vibrator was designed using longitudinal-torsional vibration. These two vibrations make rotary displacement at the end of the vibrator. ANSYS was used to determine shape and dimension of the vibrator in addition to resonant frequency, displacement and stress distribution. This kind of vibrator can be applied for a brakeless and gearless rotary motor which has high torque at low speed.

• 한국소음진동공학회논문집
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• 제19권12호
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• pp.1289-1295
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• 2009

This paper presents design and analysis of ultrasonic vibrator featuring the piezoelectric actuator. After describing a geometric configuration of the proposed vibrator, an analytical model of the ultrasonic vibrator is formulated by adopting liquid film pattern theory and wave theory. The dynamic analysis and geometric optimization are then undertaken using a software ANSYS. The optimization is performed by taking the amplitude of the tip displacement as an objective function. The fluid flow characteristics of the proposed vibrator are analyzed by taking three different fluids: water, silicon oil and ethylene-glycol. This is achieved using a software FLUENT.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.571-576
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• 1994

In recent years, ultrasonic has been widely applied in measurement and industrial fields and its application range has been expanded as a result of continuous research and development. Wire Bonding Machine, an instrument fabricating semi-conductor, makes use of ultrasonic bonding method. In order to improve the currently used wire bonding machine using ultrasonic energy, technical accumulation is needed steadily through development of exciting device of ultrasonic composed of piezoelectic vibrator and horn. This study investigates the design conditions affecting the dynamic characteristics through the theoretical and experimental analysis of piezoelectric vibrator and horn, The study conducts separately the system identification of piezoelectric vibrator in time domain and the modal analysis of horn in frequency domain. In theoretical model, the integrated modeling is conducted via a combination of dynamic identification of piezoelectric vibrator and theoretical analysis of horn. Hence comparison is made for theoretical and experimental results of the dynamic characteristics of the ultrasonic transducer composed of piezoelectric vibrator and horn. Form the results of this study we develop the design technique of ultrasonic transducer using dynamic characteristic analysis and propose the possibility of ultrasonic welding considering the optimal condition of the natural frequency and vibration mode of horn.

• The Journal of the Acoustical Society of Korea
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• 제16권3E호
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• pp.37-43
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• 1997

A frequency-variable ultrasonic vibrator is designed, which is made of a multi-layered PZT vibrator with a conical horn. Transmission line equations for the conical horn are derived and analyzed using the equivalent circuit method in order to analyze the characteristics of the vibrator. The controllability of the driving characteristics by varying the electrical impedance is confirmed by the experimental results of the free admittance characteristics and the vibrational velocity distributions.