• 대한기계학회논문집A
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• 제20권7호
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• pp.2213-2222
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• 1996

This paper presents the design process and evaluaation results of a two-axis force transducer for measuring flange reaction forces. A double-cantilever beam structure is used as a sensing element, and its optimal configuration is determined based on the derived strain equations to maximize the sensitivity and minimize the regid body displacements. To reduce the coupling errors between two-axis forces, strain distributions by finite elemetns analysis are utilized and the Wheaststone bridge cricuits composed of strain gages are built such that the output voltage should be zero, although strains of four strain gages are not zero. Calibration test shows that the two-azxis force transducer developed in this paper is useful in measuring flange reaction forces within the coupling error of 5.53%.

• 한국음향학회지
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• 제37권6호
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• pp.422-427
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• 2018

본 연구에서는 소형 물체가 음파 정상파의 압력 마디 부근에 소형 물체가 부양하는 정상파 음파 공중부양(standing wave acoustic levitation) 현상에 대해 베르누이 원리를 이용하여 부양의 원인이 되는 음향 방사힘(acoustic radiation force)의 근원과 개형을 기존에 알려진 진동자에서 떨어진 거리에 따른 음향 방사힘의 그래프와 비교함을 통해 개념적으로 설명했다. 이러한 설명을 뒷받침하는 일련의 실험들을 BLT(Bolt-clamped Langevin Type) 초음파 진동자를 이용해서 수행하여, 물체들이 공기의 압력 마디 부근에 부양하고 있음을 확인했고, 물체가 부양하고 있는 상태에서 정상파가 형성되는 조건임을 확인했다. 더불어, 정상파 음파 공중부양 현상에서 부양하는 물체들이 수직하게 일렬로 정렬하는 현상 역시 설명할 수 있었다.

• 센서학회지
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• 제11권3호
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• pp.171-182
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• 2002

이식형 인공중이에 사용되는 일반적인 전자기 방식의 진동 트랜스듀서에 비하여 두 개의 소형 영구자석을 같은 극끼리 접착한 후 코일내부에 위치시킨 차동 전자 트랜스듀서는 효율이 높고 코일-영구자석간의 공극조정이 필요 없으며 외부의 자기장에 대하여 영향을 받지 않는 특성을 가진다. 본 논문에서는 이러한 차동 전자 트랜스듀서를 이식형 인공중이 시스템에 사용하기 위하여 입력전류에 대하여 진동력의 크기를 최대화시킬 수 있는 효율적인 구조를 제안, 해석하였다. 유한요소 해석을 통하여 가장 효율적인 코일과 자석의 길이 비를 도출하였고 소리신호 전달을 위한 트랜스듀서의 필요 진동력을 산출한 후 트랜스듀서 발생 진동력을 해석하였다. 그리고 실제 이소골에 이식할 수 있는 크기의 트랜스듀서를 제작하기 위한 설계상수를 추출하였다. 계산된 설계상수를 이용하여 이식 가능한 크기로 트랜스듀서를 구현한 후 무부하 실험과 사체 부하 실험을 실시하여 제작된 트랜스듀서가 실제 중등이상 고도난청자를 위한 이식형 인공중이 시스템에 사용될 수 있음을 증명하였다.

• 한국멀티미디어학회논문지
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• 제23권8호
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• pp.1040-1048
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• 2020

In this study, in order to improve the implantable bone conduction transducer of the prototype proposed by Shin et al., the effect of the element parameters of the transducer on the frequency characteristics was analyzed using electromagnetic and mechanical vibration analysis. Electromagnetic analysis was performed on the size of the permanent magnet and the distance between the metal plate and the coil to derive an optimal structure that generates the maximum Lorentz force. In addition, mechanical vibration analysis was performed on the cantilever structure of the vibrational membrane in order to minimize the distortion of the transducer and to have a frequency characteristic suitable for conductive hearing loss compensation. The frequency characteristics of the transducer of the optimal structure derived through finite element method were compared with the simulation results of the previous transducer. As a result, the output magnitude (displacement) of the transducer designed with the optimal structure generated an average 8.8 times higher than the previous transducer, and the resonance frequency was generated at 0.9 kHz.

• Nuclear Engineering and Technology
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• 제42권3호
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• pp.319-328
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• 2010

Bonded tendons have been used in reactor buildings at some operating nuclear power plants in Korea. Assessing prestress force on these bonded tendons has become an important pending problem in efforts to assure continued operation beyond their design life. The System Identification (SI) technique was thus developed to improve upon the existing indirect assessment technique for bonded tendons. As a first step, this study analyzed the sensitivity of the key parameters to prestress force, and then determined the optimal parameters for the SI technique. A total of six scaled post-tensioned concrete beams with bonded tendons were manufactured. In order to investigate the correlation of the natural frequency and the displacement to prestress force, an impact test, a Single Input Multiple Output (SIMO) sine sweep test, and a bending test using an optical fiber sensor and compact displacement transducer were carried out. These tests found that both the natural frequency and the displacement show a good correlation with prestress force and that both parameters are available for the SI technique to predict prestress force. However, displacements by the optical fiber sensor and compact displacement transducer were shown to be more sensitive than the natural frequency to prestress force. Such displacements are more useful than the natural frequency as an input parameter for the SI technique.

• 산업기술연구
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• 제21권A호
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• pp.89-96
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• 2001

A low cost force./moment sensor that can be used in the robot teaching task is presented. Force Sensing Resistor is used as the transducer. The principle of force/moment detection is explained, the architecture of the sensor is shown, and the measurement of the force/moment is presented. The force/moment sensor shown in this work is not meant to be used in a precise force/moment control, but it is intended to be used in the robot teaching where low accuracy can be tolerated.

• 대한한방내과학회지
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• 제35권4호
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• pp.439-447
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• 2014

Objectives: The aim of this study was to investigate whether 1) variation of bowel sounds recorded stably through an electronic stethoscope in a sound insulation box can be related with that of gastric contraction and 2) if they are thus useful tool in the measurement of the gastric contractility in awake rats or not. Methods: Electrical potentials of both electronic stethoscope of bowel sound and force transducer were recorded simultaneously and continuously in the sound insulation box for the starting 30 min of basal state, and then 30 min of 0.2 ml normal saline administration, finally 30 min of 0.2 ml mosapride citrate solution (100 mg/Kg) in rats. Each motility index of normal saline or mosapride citrate treatment was presented with ratio against the basal state by using integrated electrical potentials. Results: A pattern of significance of gastric contractility between bowel sound and force transducer was showed analogously. Conclusions: The amplitude of bowel sounds recorded by the electronic stethoscope related with the intensity of gastric contractions. This confirms that a sound insulation box and electronic stethoscope are useful tools in the measurement of the gastric contractility of awake rats.

• 대한한방내과학회지
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• 제34권2호
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• pp.147-154
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• 2013

Objectives : The aims of this study was to find out whether Jichul-hwan (JCH) extract has an effect on gastric contractility in conscious rats by using a force transducer implanted in the body of the stomach. Methods : The force transducer (model: F-081S, Starmedical, JAPAN) was implanted to the exterior wall of the stomach body in rats. The gastric contractility was measured 30 minutes before and after administration of JCH (110.1 mg/kg). The control group was administrated with normal saline instead of JCH to compare the effect of JCH. The gastric contractility of the control group (normal saline: NS) was also measured 30 minutes before and after administration of NS. Results : The ratio of gastric contractility between before and after medication by JCH was $1.707{\pm}0.731$, and with NS was $0.701{\pm}0.541$. The gastric motility increased by JCH was significantly higher than NS. Conclusions : JCH extract increases gastric contractility in conscious rats. We could expect that this drug would be effective in the treatment of functional dyspepsia or post-surgical gastroparesis.

• 소음진동
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• 제5권1호
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• pp.95-106
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• 1995

Flow-induced vibration in heat exchanger (or fuel rod) in nuclar power plant can cause dynamic interactions between tubes and tube supports resulting in fretting-wear. To increase the reliability and design life of heat exchanger components, design criteria that establish acceptable limits of vibration and minimize fretting wear are necessary. The fretting-wear rate is dependent upon material combination, contact configuration, environmental conditions and tube-to tube support dynamic interaction. It is demostrated that the fretting -wear rate correlates well with tube-to-support contact force or work rate. The tube-to-support dynamic interaction, which consists of dynamic contact forces and tube motion, is used to relate single-span wear data to real heat exchanger configurations consisting of multi-span tube bundles. This paper describes the test facility to measure tube-to-support dynamic impact force and reports its dynamic characteristics through the four impact tests - a force transduces independent and external impact tests, central ring inside impact test and additional cylinder impact test. Through the tests the impact parameter change dependent upon the material difference of impacting ball is studied, and the impact parameters of Force Transducer Assembly components are measured. And also the dynamic behavior of Force Transducer Assembly is analyzed. The force measurement technique herein is shown to provide a reasonable measure of dynamic contact forces.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.1142-1144
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• 1999

A 4-beam cross type silicon elastic body was fabricated for the electromagnetic type vibration micro transducer. To improve energy transfer efficiency, the structure and size of vibration transducer were optimized by the FEA simulation package. Experimental results of the fabricated transducer shows $0.5{\sim}8$ dyne of vibration force at the condition of $1{\sim}4$ mA of current source $100{\sim}7000$ Hz of frequency band width. These results presented the useful applications for micro actuators and sensors.