Research On Magnetorheological Fluids And Transmission Technology

Magnetorheologcial Fluds (MRF) is a new type intellectual material with attractiverheological properties upon the application of an external magnetic field, has been afocused research and widely use all over the world recent years, MagnetorheologicalTransmission Device (MRTD), with superior transmission performance and applicationprospect, is an important application of MRF. According to the existing problems, thefollowing aspects are thoroughly researched in the dissertation.Conception of MRF is described and rheology effect is observed from macroscopicand microscopic aspect, performance evaluation indexs are analyzed detailedly showingthat shear yield stress is the most important performance of MRF, the characteristics ofclassic dipole model, local dipole model and finite element model are summarized,obtaining the limitation and error distribution of classic dipole model, a new type particlesinteraction model, splitting dipole model, is proposed and the error is discussed, then, anew shear yield stress theory calculation model of MRF is deduced, which has simplerformat and higher precision.Deformed interface shapes of MRTD are summarized, the magnetic field distributionin working gap and the transmission capability of oil film are analyzed repectively by thenumerical calculation method, and transmission rules of different deformation values andworking distances are obtained, the results are verfied by experiment method and theallowable deformation value is obtained.Wall slip effect generation mechanism is described and interaction relationshipbetween particles and transmission wall is analyzed theoretically. Based on a lot ofexperiments, the influence rules of wall materials, roughness, groove shapes, groovedensities, groove depths, texture types, volume fraction of MRF and applied magnetic fieldon wall slip effect are obtained respectively, the more reasonable transmission wall isobtained.A double disc MRTD is designed, of which the magnetic field and the temperaturefield are analyzed, the disc MRTD test-bed is established and the transmissioncharacteristics including no-loaded characteristic, static characteristic, dynamiccharacteristic, adjusting characteristic, temperature characteristic, slip rotato speedcharacteristic and working distance characteristic of MRTD are researched by experimentmethod.Relationship model of MRTD system between current and rotate speed is deduced and the time response is analyzed, then, the control characteristic and strategy are summarized,the fuzzy control strategy and controller are desiged, the corresponding speed adjustingexperiment is researched. The research results play a guiding role in the thorough researchon MRF and MRTD technology, and provide technical support for the design of MRTDand application and popularization of MRTD technology.