Fundamental Constitutive Modeling of Magnetorheological Fluid and its Application on Reconfigurable Systems. Semi-active Damper and Transmission Actuator

Abstract

Magnetorheological (MR) fluids belong to the general class of smart material whose rheological properties can be modified by applying a magnetic field. The most important advantage of these fluids over conventional mechanical interfaces is their ability to achieve a wide range of viscosity in a fraction of millisecond. According to bibliography and patent analyses a growing tendency around MR technology is observed and its application on reconfigurable systems is feasible. The main objective of this thesis is to describe the main parameters affecting the magnetorheological fluids by the creation of a constitutive expression that can be consider in the design of reconfigurable systems. In addition to conceptualize and to characterize two prototype systems; a semi-active damper and a transmission actuator. The thesis is divided in five chapters. First chapter refers to background analysis and aims, where the problem statement and the followed methodology are presented. Second chapter presents the state of the art, where MR technology and trends are analyzed. In the third chapter, the analysis of the MR fluid under different magnetic fields is carried out. Finally, in chapter four and five, applications related with semi-active damper and transmission actuator systems are characterized. The results obtained in this thesis are the identification of the main parameters which affect the magnetorheological fluids. Fundamental models expressions to determine the viscosity of MR to be considered in the design of reconfigurable systems are presented. Constitutive models of two kinds of systems: a transmission actuator and a semi-active damper system. Finally, due to its ability to be adjusted and its quick response to a magnetic field change, MR technology is a feasible way in the development of reconfigurable systems.