Vibration Characteristics of Sandwich Beams Partially and Fully Treated with Electro-Rheological Fluid

This experimental study investigated the vibrational properties of a sandwiched beam clamped at both ends and fully or partially treated with an electro-rheological (ER) fluid layer. Frequency response function curves were obtained and analysed in the frequency range between 10 to 1000 Hz. Three factors were investigated for its effect on the ER sandwich beam system, i.e., electric field strength, length of the ER fluid layer and applied excitation gain. It was found that the electric field strength has little effect on loss factors and resonant frequencies of the fully treated beam, except for reduced vibration in some off-resonance regions. For the partially treated beam, the length of the ER fluid layer has a significant effect on resonant frequencies, but little effect on loss factors. As the length of the ER fluid layer increases, the resonant frequencies become higher in the entire frequency range considered. It was also observed that both partially and fully treated ER sandwich beams are almost linear systems, i.e., when different excitation gain levels are applied to the beams, the frequency response function curves are unchanged.