• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1997.04a
• /
• pp.151-166
• /
• 1997

ER clutch is a device using ER fluid, so called "intelligent material" and is a controlled system with electric field strength. Current problem of this device is that the temperature of ER fluid increases when ER clutch is operating and affects the performance of ER clutch. This study was undertaken to estimate this performance variation due to temperature increase of ER fluid. Analytic power transmission relationships and the temperature increase model using the rheological model of ER fluid were developed and the dynamic model of proposed ER clutch system was constructed, also. With this relationships, effects of changing geometric, kinetic parameters of ER clutch and ER fluid properties were described and performance variations due to temperature increases of ER fluid were estimated. In conclusion, compared with neglecting temperature increase effects, a performance of ER clutch was very differential. Therefore, to achieve uniform performance of ER clutch, we have to improve thermal stability of ER fluid with a view point of material development and design carefully ER clutch considering temperature increase effects with a view point of mechanical design skill.ign skill.

• Tribology and Lubricants
• /
• v.13 no.3
• /
• pp.73-84
• /
• 1997

ER clutch is a device using ER fluid, so called "intelligent material" and is a controlled system with electric field strength. Currently, the temperature of ER fluid increases and affects the performance of ER clutch when ER clutch is operating. This study was undertaken to estimate this performance variation due to temperature rise of ER fluid. An analytic heat transfer model of concentric cylinder type ER clutch was developed and with this model, effects of changing geometric, kinetic parameters of ER clutch and ER fluid properties were described. In conclusion, compared with neglecting thermal effects, a performance of ER clutch was very differential and for uniform performance of ER clutch, we have to improve thermal stability of ER fluid. ER fluid.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.10a
• /
• pp.393-398
• /
• 1999

The temperature dependence of the viscosity was determined for an electrorheological(ER) fluid consisting of 35 weight% zeolite particles in hydraulic oil 46cSt. Thermal activation analysis were performed by changing the ER fluid's temperature from -1$0^{\circ}C$ to 5$0^{\circ}C$ at fixed electric field. According to the analysis, the activation energy for flow was about 79.64kJ/mole at E=0kV/mm. Generally, the hydraulic oil 46cSt will be operated at the temperature of about 4$0^{\circ}C$, the ER fluid's electric field dependence of viscosities were investigated at this temperature. also, the influence of adding the dispersant(Carbopl 940) on electrorheological effect of the ER fluid was discussed.

• Tribology and Lubricants
• /
• v.25 no.5
• /
• pp.285-291
• /
• 2009

In this work, durability characteristics of electrorheological (ER) fluid for damper application are experimentally investigated. ER fluid is prepared by using phosphorated starch particles and silicone oil. The field-dependent Bingham characteristics and response time for the proposed ER fluids are experimentally obtained. Experimental apparatus of durability test for ER fluid is established with cylindrical ER cylinder for mid-sized passenger vehicle. In order to evaluate the durability characteristics of ER fluid as a function of time, damping force and temperature variations are measured until one million cycles. After durability test, Bingham characteristics and response time of ER fluid are measured and compared to the initial properties. Microscopic pictures of ER fluid are taken to validate the changes of properties. The results indicate that the ER fluid can be commercially utilized in vehicle damper system with its durability performance. Moreover, the understanding of durability characteristics is essential to predict the service life of ER fluid as well as to design its applications.

• Tribology and Lubricants
• /
• v.13 no.4
• /
• pp.1-9
• /
• 1997

ER clutch is a device using ER fluid, so called "intelligent material" and is a power transmission system controlled with electric field strength. In this paper(Part III), the behavior of ER clutch under proper conditions was investigated experimentally and compared to theoretical analyses developed from Part I, II. Considering the optimum design concept proposed from Part I, the concentric cylinder type of ER clutch was designed and the experimental apparatus for the performance test was constructed. The comparisons made indicated that the power transmission model of ER clutch and the temperature rise model of ER fluid developed from Part I, II were acceptable for engineering design calculations.culations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.316-322
• /
• 2002

This paper presents the temperature-dependent hysteresis identification of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model fur the PMA-based ER fluid is identified using experimental first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.8
• /
• pp.648-656
• /
• 2002

This paper presents the identification of temperature-dependent hysteresis of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model for the PMA-based ER fluid is identified using experimental multiple first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.3 no.2
• /
• pp.67-72
• /
• 2004

Electro-Rheological(ER) fluids consist of suspensions of fine polarizable particles In a dielectric oil, which upon application of an external electric field control take on the characteristics of the Bingham solid. In this study, the temperature dependence of the viscosity was Investigated for an ER fluid consisting of 35 weight % of zeolite particles in hydraulic oil 46cSt. Thermal activation analysis was performed by changing the ER fluid's temperature from $-10^{\circ}C$ to $50^{\circ}C$. According to the analysis, the activation energy for flow of the ER fluid was 79.6 kJ/mole without applying electric field. On the other hand, with the electric field of 2kV/mm, the linearity between viscosity and temperature was not existed By changing the temperatures the viscosity (or shear stress) versus shear rates were measured. In this experiment shear rates were increased from 0 to $200s^{-1}$ in 2 minutes. Generally, the hydraulic oil 46cSt will be operated at the temperature of about $40^{\circ}C$, thus, the ER fluid's electric field dependence of viscosity was examined at this temperature. Also, an influence of adding the dispersant(Carbopl 940) on ER effect was discussed.

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

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.3 no.3
• /
• pp.86-92
• /
• 2004

This paper describes the properties of temperature-viscosity characteristics of hydrous and anhydrous electro-rheological fluids containing starch and titanium particle in silicone oil ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed to the electrically insulating silicone oil induced when electric field is applied ER fluids under electric field control have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured the couette cell type rheometer as a function of electrlc fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electrie field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200 $s^{-1}$ in 2 minutes. The ER fluid's viscosity change is very small and stable at the temperature range of $40^{\circ}C$ to $60^{\circ}C$. Therefore, applications of a new ER fluid to control systems application are suitable.