• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06b
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• pp.3-15
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• 1994

80년대 후반들어 갑자기 새로운 가치와 가능성에 대한 조명을 다시금 받게된 ER 유체는 유선 국내에서는 물론 일본에서조차 번역에서의 정확한 명칭이 분분할 정도로 아직 국내에서는 생소한 분야이다. 이웃 일본에서는 ER 유체, 전기점성 유체, 전기레올로지 유체, 일렉트로레올로지 유체, Winslow 유체라고 불려지고 있고 우리나라에서는 전기유변성유체라고도 불리운다. ER 유체는 전장을 가함으로써 점도를 변화시킬 수 있는 콜로이드 용액의 총징으로, 절연성 유체 중에, 이러한 성질을 갖는 미분말을 분산시킨 것이다. 이 유체의 특징으로는 전장으로 점도의 변화를 제어할 수 있고, 점도를 변화 시킬 수 있는 범위가 넓고, 또한 응답성이 좋은 것에 있다. 80년대에 들어 서면서, 전자기술의 급속한 발전으로 이 ER 유체의 장점에 ER 유체의 단점을 보완할 수 있는 응답성이 빠른 전자 제어 기술의 출현은 바로 이 ER 유체의 최대 난점들을 해결할 수 있는 가능성을 제시하면서 급속한 인기를 더해 가고 있다. 이러한 배경에서 국내에서도 이분야에 대한 연구의 필요성이 대두됨에 따라 본 해설에서는 국외 논문, 국제 학술회의 논문집, 해설등을 통하여 발표된 ER 유체에 대하여 알아 보고 이를 적용한 기전요소에의 응용에 대하여 살펴보기로 한다.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.27-36
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• 2003

The Electro-Rheological (ER) fluid has been used to the ultraprecision polishing of single crystal silicon as new polishing slurry whose properties such as yield stress and particle structure changed with the application of an electric field. In this work, it is aimed to find the effective parameters in the ER fluid on material removal in the polishing system whose structure is similar to that of the simple hydrodynamic bearing. The generated pressure in the gap between a moving wall and a workpiece, as well as the electric field-induced stress of the mixture of ER fluid-abrasives, is evaluated experimentally, and their influence on the polishing of single crystal silicon is analyzed. Moreover, the behavior of abrasive and ER particles is described.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.8
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• pp.612-618
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• 2003

A hybrid vibration control scheme using ER fluid and PZT patches is proposed. Dynamic characteristics of the beam embedded with the ER fluid can be controled by changing the strength of the electric field applied on the ER fluid, thus provides a mean to avoid the resonance. It was found that active vibration control of the structure embedded with ER fluid failed to suppress the vibration excited with broad band frequency due to the limited change of the dynamic characteristics of the structure. To compensate this limited effect of the control scheme with ER fluid alone, PPF control using PZT patches as sensors and actuators is added to construct a hybrid controller. Experimental results suggests that proposed hybrid controller is effective to suppress the additional resonance vibration that appears when each controller is used alone.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.4
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• pp.1-10
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• 1991

본 글에서는 지금까지 알려진 SMS 부류에 속하는 것으로서 가장 잠재적 응용가치가 큰 것으로 인식되며 특히 자동차 산업과 관련하여 미국, 일본 등에서 활발히 연구 개발중에 있는 전기점성(electro-rheological : ER) 유체의 전반적인 세계연구동향, 이론적 배경 그리고 응용성에 관하여 소개하고자 한다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.41-47
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• 2007

The structure of ER valve is simple that its designing and manufacturing are easy. The flow rate and pressure of ER fluids flowing in the ER valve are controlled only by electric field. In this study a three port ER valve is designed and manufactured. Then, the flow rate and pressure dorp of ER fluids flowing in the ER valve are measured. The system proposed controls flow rate and pressure fast. So, this system can be easily substituted for the existing hydaulic and pneumaitc control system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.32-37
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• 2005

Several types of smart materials and control scheme are available to adjust the structure actively in various external disturbances. A control scheme was introduced for a specific material. But the effectiveness of the control scheme has some limitation according to the choice of the smart materials and the response of the structure. The ER(Electrorheological) fluid is adequate for a large control force, and the PZT(lead zirconate titanate) patches are suitable for small but arbitrary control force at any point of the structure. It can be used for active control of structure by changing the dynamic characteristics of the structure. But it has some difficulty in suppressing the excited vibration in broad band. To compensate this resonance of the controlled structure, a hybrid controller was constructed using PPF(Positive position feedback) control with PZT and ER fluid control.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.451-456
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• 2002

This paper describes the properties of Temperature-Viscosity characteristics of hydrous and anhydrous ER fluids containing starch and titanium particle in silicone oil. ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed in the electrically insulating silicone oil induced when electric field is applied. ER fluids under electric field have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured on the couette cell type rheometer as a function of electric fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electric field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200/equation omitted/ in 2 minutes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1123-1126
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• 2003

In this research 4 plate type ER-Valves which have same surface but different width and length are designed and an experimental apparatus is constructed. With this experimental apparatus, flow rate and pressure drop of ER fluid flowing in ER-Valve are measured by varying electric field strength of ER-valve, and relation between valve types and pressure drop is also experimented. ER fluid is made silicon oil mixed with 40wt% starch having hydrous particles. The pressure drop according to the strength of electric field by differential pressure gauge in the present ER-Valve was used. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.78-83
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• 2003

Electro-rheological(ER) fluids are suspensions in which rheological properties show an abrupt change with variation of electric fields. We modeled the parallel-plates relating to ER-Valve system and yielded shear stress according to the strength of electric field. The purpose of the present study is to examine the flow characteristics of ER fluids according to the strength of electric field between parallel-plates. Then the steady relationship between pressure drop and flow rate of the ER fluids between parallel-plates under application of an electric fields was measured. The pressure drop and flow rates of ER fluids under the application of electric fields for steady flow were measured. For the experiment, we used the ER fluids, 35w% zeolite having hydrous particles and differential pressure gauge. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.48-55
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• 2003

This study investigates the effect of temperature and electric field strength on the Bingham characteristics of Electro-Rheological(ER) fluids which change their Yield shear stress and viscosity by temperature and electric field strength. It is found that under constant temperature the Yield sheal stress and viscosity of ER fluids proportionally increase with the applied electric field strength, and under constant applied electric field strength the Yield shear stress and viscosity of ER fluids decrease with the increasing temperature. These results are considered to be applied to the fluid and pneumatic power industry.