Performance characteristics of a vibration isolator with electro-rheological fluids

The conflicting requirements on the damping capacity of a vibration isolato r in the low-and high-frequency regimes can be achieved by actively control ling a damper with electro-rheological fluid. Experimentally obtained resul ts on two colloidal suspensions, one based on silica powder and the other o n starch powder, are reported. While both demonstrate considerable reductio n in the near-resonance transmissibility, the starch based fluid exhibits C oulomb damping characteristics at a high field strength. This, in turn, res tricts the transmissibility to less than or equal to unity at all frequenci es even when the isolator is used in a passive manner. (C) 1999 Academic Pr ess.