Experimental study on electro-rheological material with grooved electrode surfaces

The dynamically tunable capability of a sandwich beam with embedded electro-rheological material has been proven to be a viable tool for the vibration control of structures. The effectiveness of this technique depends largely on the ER effect caused by the applied electric field. This ER effect is determined by the formation of the chain-like structures between the electrodes. In this study, the surfaces of the electrodes were modified with parallel grooves in different spacing — 0.5, 1 and 2 mm, respectively. These modified electrodes changed the local electric field distribution. Therefore, the chain-like structures formed by the suspension particles of the ER material upon the application electric field were altered. The dynamic characteristics of both the ER material within the parallel-plate fixture and the ER sandwich beam with modified electrodes were measured. The results showed that with finer spacing of the grooves on the electrodes, the ER material demonstrated greater increases in both the storage modulus and the damping loss factor upon the application of the electric field. Compared to its counterpart with plain electrodes, a 20% greater increment in the first two modes’ resonance frequencies was achieved with the proposed surface modification on the ER sandwich beam at an applied electric field strength of 1.0 kV/mm.