| Summary: | 博士 === 國防大學中正理工學院 === 國防科學研究所 === 94 === Electrorheological fluids (ERF) are a class of special fluids. The rheological properties (viscosity, yield stress, shear modulus, etc.) of which could reversibly change by several orders of magnitude under an external electric field with the strength of several kilovolts per millimeter. Since its mechanical properties can be easily controlled within a wide range almost from a pure liquid to a solid , the ERF could be widely used in various fields of mechanical applications, such as actuators, vibration suppressions and isolations, hydraulic valves, robotics, and intelligent action mechanism. Its excellent mechanical controllability can largely reduce the device complexity and cost, improves the control performance of the system, and accomplishes the functions which conventional mechanical devices are hardly to achieve. Since the ERF has a great potential in applications, such as aeronautics and aviation, production automation, armament control, robotic engineering, noise control, automobile engineering, watercraft engineering, hydraulic engineering, agriculture machinery and physical exercising apparatus, the ER techniques are broadly researched in the past half century.
In this paper, advances in material aspects of ERF are completely reviewed, Properties and problems of different ER systems, such as simple dispersed phase ERF, composite dispersed phase ERF and liquid crystalline polymer ERF, are analyzed. To acquire recent development in ER materials and to promote investigate of the new ER materials in future. The influences of the structure (core-shell or single solid phase) and the material of dispersed particles on electrorheological effects have been theoretically investigated based on the dielectric polarized model and conductive model, respectively. The results have shown that the inter-particle forces in electrorheological fluids are apparently enhanced after using the core-shell structural suspended particles rather than using single phase solid particles. However, the replacing material or coating material must have a higher dielectric constant (conductivity) than that of the original particles either changing the core material of core-shell particles or coating a shell material on the single phase solid particles, to promote the ER effects.
|
|---|
