Search Results

Electrorheological (ER) fluids have received a great deal of attention in the past decade. The promise of valves with no moving parts and simple damping devices have led many scientists to investigate this intriguing technology. Typically, though, these materials have exhibited shortcomings due to low strength and a narrow temperature range of operation. Recent advances in electrorheological fluid technology, as well as in the development of magnetic analogs to electrorheological fluids have led to the availability of controllable fluids that exhibit high strength, low viscosity and stability over a broad temperature range. This paper discusses the properties exhibited by these “new” electrorheological and magnetorheological (MR) fluids, as well as the feasibility of using these fluids in a variety of controllable devices.

Electrorheological fluids (ER fluids) are materials with the potential to radically change the way electromechanical devices are designed and operated. Working from constitutive equations of the basic ER fluid phenomena, equations for assessing the feasibility of using ER fluids in clutches, dampers, and mounts can be derived. Using these equations, the impracticality of using currently available ER fluids in primary suspension dampers and power train clutches can be clearly demonstrated. The practicality of using current ER fluids in engine mounts can also be demonstrated. Finally, the feasibility assessments of the clutch and dampers can be used to determine the improvements necessary in the performance of ER fluids which will make these applications feasible.

A tunable hydraulic mount has been designed to overcome the limitations in hydraulic mounts. The tuning of the new hydraulic mount is acheived by incorporating electro-rheoiogical fluids (ER fluids) into the mount. The design of the tunable ER fluid mount allows the stiffness resonances and anti-resonances to be tuned to several discrete frequencies. Mount models have been derived and the models have been validated by comparing simulated and measured results. These results demonstrate the mount versatility in specific applications and in studying the performance of a suspension system using hydraulic mounts.