• KSTLE International Journal
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• 제2권1호
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• pp.71-74
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• 2001

The electrorheological(ER) performance of a chitosan sebaciate suspension in silicone oil was investigated by varying the electric fields, volume fractions of particles, and shear rates, respectively. The chitosan sebacicate susepnsion showed a typical ER response caused by the polarizability of an amide polar group and shear yield stress due to the formation of multiple chains upon application of an electric field. The shear stress for the suspension exhibited a linear dependence on the volume fraction of particles and an electric field power of 1.88. On the basis of the results, the newly synthesized chitosan sebacicate suspension was found to be an anhydrous ER fluid.

• KSTLE International Journal
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• 제5권2호
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• pp.49-51
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• 2004

The electrical and rheological properties pertaining to the electrorheological (ER) behavior of chitosan derivatives, chitosan, chitosan ammonium salt and chitosan phosphated suspensions in silicone oil were investigated. Chitosan derivative suspensions showed a typical ER response (Bingham flow behavior) upon application of an electric field. However, chitosan phosphate suspension exhibited an excellent shear yield stress compared with chitosan and chitosan ammonium salt suspensions. The difference in behavior results from the difference in the conductivity of the disperse phases due to the difference of their polarizability. The shear stress for the chitosan, chitosan ammonium salt and chitosan phosphate suspensions exhibited a linear dependence on the volume fraction of particles and 1.18, 1.41 and 1.67 powers of the electric field. On athe basis of the experimental results, the newly synthesized chitosan dervative suspensions found to be an ER fluid.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1441-1444
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• 1996

This paper presents the position control of a double-rod cylinder system activated by an electrotheological(ER) valve unit. Following the composition of a silicone oil-based ER fluid, theological properties of the ER fluid are experimentally tested as a function of imposed electric fields to determine appropriate design parameters of the ER valve. The ER valves are then designed and manufactured. Subsequently, the pressure drop of the ER valve is evaluated with respect to the intensity of the electric field. Four ER valves bridge-cylinder system is formulated, and the governing equations for the system are derived. A neural network control scheme is then synthesized to perform the position control of the cylinder system. Tracking control responses are experimentally evaluated and presented in order to demonstrate the effectiveness of the proposed control system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.79-79
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• 2010

In this paper, we present results of the dielectric breakdown test in various 6.9kV power cables used in power plants. The dielectric strength of the different conditioned cables was measured by placing the sliced cable sections in silicone oil bath with needle electrode. The results were analyzed by the Weibull distribution. The shape and scale parameters of the Weibull distribution for each cable sections under test were calculated and evaluated. Collected data base was applied to deterioration trend analysis and lifetime guide was also proposed.

• 한국기계가공학회지
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• 제3권1호
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• pp.84-89
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• 2004

This study is a basic one for application of ER Fluid to fluid power systems. By mixing silicone oil with zeolite particles, four kinds of ER fluids were made, in which the weight ratio of zeolite particles are different. We examined how the Yield shear stress and Bingham characteristics of the ER fluids are effected by varying electric field intensity. We designed and constructed a disk type power transmission clutch in which ER fluid fills and this ER fluid transmits the power of drive shaft to the driven shaft. With this equipment, the revolution transmission ratio from the chive shaft to the driven shaft by varying electric field density of the ER fluid was examined.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.66-71
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• 2001

In this work, an ER clutch has been constructed and its characteristics have been evaluated by adapting an electro-rheological fluid(ERF) as an operating medium. ER fluids are suspensions which show an abrupt increase in rheological properties under electric fields. An ER clutch system using ER fluid is a new conception device because an apparent viscosity of ER fluid can be changed by apply an electric field. As a first, Bingham properties of ER fluids are experimentally distilled as a function of electric field. We use the disk type ER clutch in which the ER fluid fills the annular space between a pair of coaxial disk electrodes and experiment results show that the measured revolution per minute was increased with the increase of the electric field. The ER fluid used in the present study consists of weight fraction 35% in zeolite suspended silicone oil.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.165-170
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• 2001

This paper presents performance analysis of two-linked robot system using ER (electro rheological) valve actuators. An ER fluid consisting of soluble chemical starches (particles) and silicone oil is made and its field-dependent yield stress is experimentally distilled using electro-viscometer. From this result, the design parameters of ER valve are determined. Based on parameter study, an ER valve system is designed and manufactured. Furthermore, the measured pressure drop is compared with predicted one obtained from the Bingham model. Following the evaluation of field-dependent pressure drop of ER valve, a two-linked robot system with two ER valve actuators is then constructed and its governing equation of motion is derived. From this equation, PID controller is established. Consequently, control performances of the proposed two-linked robot system featuring ER valve are evaluated.

• 대한기계학회논문집B
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• 제28권2호
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• pp.154-159
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• 2004

A new microflow rate controller for medical injection was developed and evaluated. The flow rate was controlled by changing the friction depth as well as the friction length of the micro-channel. A precise micro-fabrication of the micro-channel was requested for an accurate flow control. The friction depth was inversely proportional to the friction length, which gives a linear flow control to the channel length. The channel groove was fabricated with a plastic material. A rubber containing silicone oil was covered over the groove, which satisfies both lubrication and leakage prevention. The flow controller was validated by performing the numerical simulation and experiment. A good agreement was shown between computation and experiment.

• Korea-Australia Rheology Journal
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• 제18권1호
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• pp.25-30
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• 2006

To enhance the stability of dispersed polyaniline (PANI) particles in a silicone oil system, a nonionic surfactant was adopted, and its effect on the electrorheological (ER) performance was investigated under an applied electric field. In the presence of a nonionic surfactant, the PANI based ER fluid exhibited not only an improved sedimentation stability based on the estimated sedimentation ratio but also an enhanced maximum yield stress behavior. Furthermore, the surfactant added ER suspension was applied to an ER damper system, and its damping performance was compared with the ER suspension without a surfactant.

• Journal of Magnetics
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• 제20권3호
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• pp.317-321
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• 2015

In this paper, magnetorheological fluids (MRFs) based on micro-sized iron particles dispersed in silicone oil are presented. The iron particles are modified by adding different ratios of oleic acid and lauric acid as surfactants to the suspensions. Lauric acid was found to reduce the stability of the MRFs, and more lauric acid results in a higher rate of sedimentation. Further study showed that the formation and structure of lauric acid may result in the sedimentation of micrometer-sized particles. Meanwhile, the electro-resistance of MRF in this paper shows a decrease from beyond $6000M{\Omega}$ to $190{\Omega}$ with an increase in the external field from 0 mT to 400 mT.