Testing of High-Force ER Dampers

Electrorheological (ER) suspensions represent a broad class of materials which exhibit reversible property changes when subjected to high electric fields. Specifically, material properties change from those of a Newtonian liquid to a those of a viscoelastic-plastic solid, within milliseconds, and with very little required external power. The adaptable behavior, and simplicity, of these materials are attractive features in implementing semi-active (variable-damping or variable-stiffness) vibration control. Because the ultimate behavior in ER materials is yielding, the stresses in these materials are limited, and are typically small compared to the stresses in structural materials. Therefore, in designing high force ER devices, the material must be designed to flow over large surface areas. One embodiment of this design consists of multiple concentric annular flow ducts. This paper presents preliminary experimental results from one such design.