Shear stress analysis of a semiconducting polymer based electrorheological fluid system

The feasibility and effectiveness of electrorheological (ER) and magnetorheological (MR) fluid-based landing gear systems on attenuating dynamic load and vibration due to the landing impact are demonstrated. First, the theoretical model for ER/MR shock struts, which are the main components of the landing gear system,is developed based on experimental data. The analysis of a telescopic-type landing gear system using the ER/MR shock struts is theoretically constructed, and its governing equation is derived. A sliding mode controller, designed to be robust against parameter variations and external disturbances, is formulated, and controlled performance of the simulated ER/MR landing gear system is theoretically evaluated during touchdown of the aircraft.

Vibration Control of a Landing Gear System Featuring Electrorheological/Magnetorheological Fluids

The demand for low cost, quiet operation, and increased operator comfort in automobiles and other applications is requiring that new techniques be developed for noise and vibration isolation. One a...

A magnetorheological semi-active isolator to reduce noise and vibration transmissibility in automobiles

Electrorheological (ER) and magnetorheological (MR) fluids show similar field-dependent rheological characteristics from a bulk fluid perspective. However, the implementation of ER and MR fluids in devices may require different strategies because of the inherent properties of ER and MR fluids such as density, viscosity and the magnitude of the yield stress. Therefore, in this study, we explore the characteristics of ER and MR fluid-based systems on the basis of dynamic range and time response in order to comprehensively understand each system. In doing so, a nondimensional analysis, based on parallel plate geometry, is used to characterize the field-dependent properties of ER and MR fluid-based dampers. Experimental tests are conducted for ER and MR dampers in order to validate our analysis.

Comparative Analysis of the Time Response of Electrorheological and Magnetorheological Dampers Using Nondimensional Parameters

Among various materials suitable for an electrorheological (ER) fluid, polyaniline and its many derivatives based upon modification of oxidation state, dopant and polymerization conditions are of technological interest for their adaptation into ER fluids. This is because they have better thermal stability and smaller density than other potential ER materials. Furthermore, polyaniline is easy to polymerize by oxidation polymerization at relatively low temperature and can be doped from a conducting emeraldine hydrochloride form to an insulating state using simple protonic acids. In this study, we adapted the polyaniline based ER fluids for semi-active cylindrical flow-mode type ER damper. A cylindrical flow-mode type ER damper was chosen in this study because it has similar geometrical configuration to the conventional damper normally used for passenger vehicle. The damping forces measured using a semi-active ER damper with polyaniline based ER fluids were found to be controlled by tuning an applied electric field for different piston velocity.

Electrorheological semi-active damper: Polyaniline based ER system

This paper presents field-dependent Bingham and response characteristics of ER fluid under shear and flow modes. Two different types of electroviscometers are designed and manufactured for the shear mode and flow mode, respectively. An ER fluid consisting of soluble chemical starches (particles) and silicon oil is made and its field-dependent yield stress is experimentally distilled at two different temperatures using the electroviscometers. Time responses of the ER fluid to step electric fields are also evaluated under two operating modes. In addition, a cylindrical ER damper, which is operated under the flow mode, is adopted and its measured damping force is compared with predicted one obtained from Bingham model of the shear and flow mode, respectively.

H. G. Lee

Papers

Bingham and Response Characteristics of ER Fluids in Shear and Flow Modes