Study On Stability Behaviors Of Magnetorheological Fluid

Due to its mechanical simplicity, high dynamic range and low power requirements Magnetorheological(MR) fluid device based on controllable rheological behaviors can mesh well with vital demands and constraints to offer attractive means of protecting civil infrastructures against earthquakes, of improving monarchical systems against vibration and upgrading armament systems against impulsion. It is very important to contribute the MR fluid with stability behavior for MR fluid engineering application, but as the constitution of MR fluid and use condition are complex, to complete the stability behavior of MR fluid is difficulty. Much attention has been paid to study on the stability behavior of MR fluid material, although several works were done for improve the stability behavior of MR fluid at home and over sea, the result is un-ideal. According to the constitution and principle of MR fluid, some methods for improve stability behavior of MR fluid has been presented, for example, the thixotropic agent and surfactant is compounded, the surface of magnetic-responsive particles is refinished, the solid lubricating and the magnetic liquid is used. Primary researches in this dissertation are stated as follows:According to the deposition or aggregation stability behavior, temperature stability behavior and lubricating stability behavior of MR fluid , state-of-the-art and development tendency of MR fluid stability studying have been summarized. Having analyzed some existing issues in MR fluid stability researching, and author narrates significances of research in this dissertation.In this paper, the rheological characteristic of MR fluid and the principle on deposition stability behaviors in gravitation field have been analyzed, some constitutive models, including in Bingham model, Herschel-Bulkley model are characterize rheological behaviors of MR fluid, author comes to the method that MR fluid stability behaviors can be improved by suitable refinishing on the surface of magnetic-responsive, and suitable using additive, and the magnetic liquid is used to carrier fluid, and the suitable distribute of responsive particles with different diameter.According to thermodynamics theory, molecule and crystal structure theory, and charge distribute theory of MR fluid, the principle on thixotropic agent are analyzed. According to the types and molecule structure of surfactant,the analytical relationships between hydrophobe effect and surface activity of MR fluid, some experiments that the stability behaviors of MR fluid are influenced by Fe/PMMA responsive, additive agent and magnetic liquid have been conducted. whose result show that stability behaviors of MR fluid are excellent.The basic theory that improve the heat stability of MR fluid are known based on the temperature characteristic of every MR fluid component. According to thermodynamics and energy change theory, the analytical relationships between adsorption and temperature in the MR fluid are comprehensively established, and the analytical relationships between off-state viscosity and temperature are comprehensively established too. Some methods that improve lubricating behavior of MR fluid have been established by oxidizing or electroplated techniques on the particles surface and solid lubricating techniques, the MR fluid was used to"four-ball-grind"test or MR fluid damper durability test and achieved excellent result.