Experimental and analytical methods for predicting mechanical properties of MRF damper

First part of this paper covers experimental studies on mechanical properties of two types of magneto-rheological fluid (MRF) dampers. One is a commercial built-in-pass type damper and the other an original by-pass type damper. In the test, they are subject to cyclic sinusoidal displacements with different amplitudes, velocities and intensities of magnetic field. Not only their hysteretic properties but also their quickness to respond to the applied magnetic field are examined. In the second part, two analytical methods to represent the mechanical properties of the dampers are presented. One is a semi-empirical method making use of a Bingham Model to simulate the hysteretic properties of the damper. The other one, an analytical method based on the theory of non-Newtonian fluid. A design formula to predict the resistance of the damper is so obtained as to take into consideration the damper's dimensions, the properties of the fluid and the intensity of the magnet field applied.