Electro-rheological and Magnetorheological Fluid based Dampers

A typical use of ERF for vibration isolation is shown in Figure 36.1.

Figure 36.1: Isolator with ER fluid

The vibration isolator consists of a parallel combination of a helical spring and a piston-cylinder dashpot with ERF. It has been observed that with suitable combination of particle concentration, carrier fluid and the strength of the electric field the damping characteristics of the dashpot can be varied over a wide range. At high field strength even Coulomb damping characteristic (rather than viscous) can be achieved.
ERF can be used for both passive and active vibration isolation. In case of passive isolation, a fixed field could be applied to achieve Coulomb damping characteristics. However, for optimal use over a broad frequency range, one can actively control the electric field to the ERF mount for vibration control.