Development and Experimental Investigation of MRF Damper Behavior under Triangular Excitation of Damper Input Current

Abstract

Magneto-rheological (MR) fluids are materials that respond to an applied magnetic field with a dramatic change in rheological behavior. An MR fluid will be in a free-flowing liquid state in the absence of magnetic field, but under a strong magnetic field its viscosity can be increased by more than two orders of magnitude in a very short time (milliseconds) and it exhibits solid-like characteristics. The strength of an MR fluid can be described by shear yield stress. Moreover, the change in viscosity is continuous and reversible, i.e. after removing the magnetic field the MR fluid can revert to a free-flowing liquid. Using these characteristics of MR fluids, MR fluid devices have the ability to provide simple, quiet, rapid-response interfaces between electronic controls and mechanical systems. Hence scholars and industrialists have shown extensive interest in MR fluids and their applications. The devices based on MR fluids, including dampers, clutches, polishing devices and hydraulic valves, etc., have a very promising potential future; some of them have been used commercially in engineering applications such as automobiles, polishing machines, exercise equipment, etc. The focus of this research is to develop a fundamental understanding of MR dampers for the purpose of designing and implementing these “smart” damping devices in automotives and structures for vibration mitigation. The damper is to be designed, developed and tested for different configurations i.e. changing the MR fluid, changing the material of the housing, changing the gap dimension, changing the coil wire diameter and increasing the number of steps of the coil. The study in this research is intended to provide insight into the behavior of MR fluid dampers and their potential applications to various vibration problems. This work is expected to accelerate the implementation of these dampers in the areas of vibration mitigation in mechanical and civil engineering applications.